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Photometry is a technique of measuring light in terms of its perceived brightness to the human eye. In chemistry, it is commonly used in the study of solutions and liquids. Since its conception, scientists have strived to increase the accuracy and precision of elemental concentration determinations via instrumentation. This search has culminated in the development of modern-day Inductively Coupled Plasmas (ICPs), coupled with a detection method such as a mass spectrometer. As we have already made a posting on inductively coupled plasmas before, this time we shall be focusing on the heating method and the plasma itself. The heating method The method by which the sample is heated is via an induction coil. Inductive heating is the process of heating an electric conductor material via Eddy currents (current which are looped via a magnetic field). The components that are essential to this technique are: · An electromagnet · An electronic oscillator · A rapidly altering magnetic field · An inert gas How does Inductively Coupled Plasma work? The most important factor in ICPs is that the heat energy released from the induction coil is generated from within the coil, instead of being conducted from an outside source. In flame photometry, meanwhile, the gasses combustion is the source of energy which is conducted into the analyte of interest. What are the variables in using Inductively Coupled Plasmas? When using ICP instrumentation, instead of air being the gas of choice to aid in the combustion of fuels such as in flame photometry, an inert gas is used (such as neon or radon). This is because of the intense heats involved in induction heating results in all of the electrons of an atom being stripped in plasma formations, leading to emission lines being given out from the carrier gasses. A gas is still essential to be used as a kinetic energy driving force to turn the sample from a liquid into a fine mist through the application of a nebuliser – a part which is found commonly in both ICP and flame photometers. Due to ICP being only a heating device in an instrument that is capable of plasma formation, a detection method must be added, such as a mass spectrometer or a UV-Vis light spectrometer.

A flame photometer is a scientific instrument which is based on flame testing. But how is it used in the real world for testing and measuring? Experts generally use it to measure the concentration of ionic species in aqueous solutions. In layman’s terms – identifying chemicals in water-based solutions. However, flame photometry is used around the world every day within a number of different industries. What is flame photometry? Flame photometry is the process of measuring the intensity of light emitted when an element is exposed to a flame, using a wavelength of a colour. Not all elements are detectable by flame photometry. When it comes to detecting the concentration of an element via flame photometry, said element must exhibit a specific set of prerequisites to make it suitable for analysis. You can usually split most samples up into two different categories: a liquid sample or a solid sample that must be turned into a liquid. The liquid of choice is normally water; however, it is not uncommon for liquid samples to also contain other liquids, such as hydrocarbons like oils or alcohol. Using photometers in the food industry A very common use for photometers is within the food industry. Salt levels in the last century have started to be closely monitored for health reasons, as too much salt can cause high blood pressures and a whole host of other health issues. Another common use for photometers in the food industry is to detect for the presence of sugar in water. This is carried out via using a potassium standard, which is mixed with the flow of water that may or may not contain sugar. If a rise in potassium levels is detected from the temperature increase, then sugar is present. This is what is known as an indirect qualitative determination, as you are not directly determining the concentration of sugars in the sample, but instead establishing a yes or no answer to there being sugars present in the solution. Using photometers in healthcare Another common use for photometry is the detection of lithium is blood samples. Lithium Carbonate is commonly used to treat Bipolar disorder. However, if not carefully regulated in the body, it can cause issues with diabetes and the central nervous system, as well as renal failure. Another use for photometers is looking at urine samples to detect irregularities in ion levels, which can be a signal of kidney damage due to it not properly filtering out important electrolytes from the body. Other uses for flame photometers It may be odd to hear but testing drinking water is usually not carried out via a flame photometer due to its limited analytes that it can detect. It usually is detected via an ICP-OES instrument so that a huge range of elemental analysis can be carried out to test for heavy metal contaminants.

Lithium is a chemical element with the symbol Li. A soft, silvery-white alkali metal, it is actually the lightest-known metal on Earth, as well as being the lightest-known solid element. It is very similar to sodium, being that it is from the same group of alkali metals, can be easily cut with a knife and will also oxidise to a dull grey colour when cut. Also, like sodium, lithium must also be stored in oil to avoid it reacting with water violently and is not found in its metallic state in naturally occurring deposits. Where is lithium found? Chile is believed to have the largest known lithium reserves in the world with eight million tonnes, some five or six tonnes more than Australia and Argentina, and seven more than China. You can also final smaller quantities of the valuable raw material in Portugal. What has lithium historically been used for? Over the last century, lithium has played an important role in humanity's interactions with radiation and nuclear research. It was the very first transmuted element from lithium to helium in 1932, which was the first man-made nuclear reaction. In early-stage nuclear weapons, lithium deuteride served as a fusion fuel for staged thermonuclear weapons. What is lithium used for today? With its strong red-coloured flame, lithium is commonly added to flares and fireworks as it gives off such a bright spark. Another interesting use of lithium is the formation of large Lithium Flouride crystals by applying a high amount of force to them. What makes these crystals unique is that they are one of the lowest refractive index materials known to man, and therefore have found their way into use in optics for IR spectrometer and UV spectrometry. What made this application so popular is that they can be made with the use of a hydraulic press in the laboratory. When used in combination with manganese dioxide or thionyl chloride and many other molecules in a cell, a lithium battery is formed. These batteries are very long life and stable and are used in applications from standard AAA batteries to pacemakers, where changing a battery becomes invasive to the user of the pacemaker. How is lithium used in medicine? Lithium carbonate (Li2CaO3) is a commonly used antidepressant to treat Bipolar disorder, Schizophrenia and major depressive disorder. However, due to there being a limit to the body's ability to cope with high concentrations, the blood levels of lithium must be monitored. This is commonly done by using a flame photometer and blood serum. How are concentration levels of lithium measured? Here at BWB Technologies, we have now produced a specialised instrument specifically to determine concentrations of lithium. It is one of the most advanced flame photometers, with the sole purpose of the analysis of a single element in mind using multiple detection channels for highly stable readings of concentration.

Flame photography is the process of measuring the intensity of light emitted when the element is exposed to a flame, using a wavelength of a colour. However, not all elements are detectable by flame photometry. When it comes to detecting the concentration of an element via flame photometry, said element must exhibit a specific set of prerequisites to make it suitable for analysis. What are the requirements for an element to be suitable for Flame Photometry? One of the primary requirements is that the element can be ionised into its ionic form in aqueous solutions. While this does not cut the pack of elements available down by a large margin, a substantial number of non-metals are instantly removed. One of these is carbon, which is commonly oxidised to become water soluble, while other elements include silicon, sulphur and oxygen. This is based upon the electronegativity of the element, which increases as you move up and right across the Periodic Table. What is Charge Density? Another factor which makes it commonplace to see the determination of elements in the alkaline and alkaline earth periods is charge density. Charge density is a measurement of the atom’s overall charge (1+ and 2+ for elemental alkaline and alkaline earth elements) divided by the size of the atom. As the charge density of these elements, as well as the low number of electrons present in their outer shell of electrons, is low, the requirement for energy to excite the element is reduced. This is due to the effect of the nucleus's overall magnetic charge in comparison to the strength of a single electron and the stability gained by releasing the electron, which is commonplace in metallic bonding of these pure elements. Why is it difficult to select elements for analysis via Flame Photometry? The issue with measurement of transition metal elements and larger metallic elements when selecting them for analysis via flame photometry is that due to the presence of the outer shell being a D orbital, the excitation of an electron occurs in a differing manor to that of a P orbital because of their vastly differing shapes. This leads to a lot of more different pathways for an electron to relax into. Therefore, the spectrum of light emitted from the excitation of transition metal elements is broader and less defined than that of an element that is suitable for detection via flame photometry.

Are they the same thing? It can be easy to confuse energy levels and electronic orbitals. Understanding what actually occurs to an electron when it is promoted to a higher energy level is an interesting piece of information that can go amiss. Nearest neighbour distance r and distance between one excited ion and the nearest ion in the ground state r exÀgr for both only few excited ions (a) or a larger number of excited ions (b). What is an excited ion? When discussing the excitation of ions in a flame photometer, an electron is promoted to a higher energy level which, in turn, makes the ion what is known as ‘excited’. This ‘excited’ ion is then ready to decay back to its ground state and emit or radiate a packet of energy in the form of a photon. The photon’s wavelength and frequency are derived from the difference in the decay from the excited state to the ground. What happens to the energy levels? The energy levels which can be occupied are static for each element, but they can be altered by factors including dative covalent bonds. An electron cannot partially reach a higher energy level and then drop back down to a lower one; it must have the full requirement of the energy required for the jump to an increased level of energy. This energy requirement is what is known as the activation energy. Can you increase the energy of an electron? Electrons also have a shell in which they are spatially located, such as the S, P, D and F orbitals. However, increasing a S electron to a higher energy state does not push this electron spatially out of its shell. Increasing an electron’s energy only increases is angular momentum. Does the temperature increase as a result? It would be easy to think from this explanation that temperature, which is a form of energy expressed through the vibration of molecules, should also increase in these set energy levels. This is not that case. This is because electrons being promoted to a higher energy level are not the only form of energy that a molecule can store. Other forces such as the molecule’s momentum as it moves and collides with other molecules is a form in which energy can be transferred between them. Just to add more confusion into dealing with how to picture the electrons and how they exist within our current scientific knowledge, it should be remembered that electrons cannot be fully categorised as either a particle or as a wave. This will be discussed in an upcoming blog post continuing our topic of electrons and their vital importance to practically every physical object we could imagine.

The origins and history of the scientific method. We do not learn by accident – for generations scientists, mathematicians and thinkers have developed scientific method to progress the human race’s knowledge. From the scholars of ancient Egypt to the 18th century naturalists, the use of scientific method has evolved remarkably over the centuries. What is the scientific method? The scientific method is a process of critical thinking that involves forming a hypothesis based on observations and rigorously questioning what is observed with a healthy degree of scepticism. It usually begins by asking a question, followed by background research and forming a hypothesis about that question. For example: “If I do X with Y then Z will happen.” Then the hypothesis is experimented on, data is drawn and analysed, before a decision can be made on whether the experiments’ results match the hypothesis. Finally, the results need to be communicated. History of the scientific method The earliest found physical evidence of applying observations to the solving of problems is generally accepted to be Edwin Smith Papyrus in Egypt, estimated to be from 1600BC. His medical textbook had four steps - examination, diagnosis, treatment and prognosis. There is plenty of evidence to suggest that the Arabic world was a long way ahead of Greek and Roman scholars in the west, in terms of knowledge and understanding of the world. In Mesopotamia the Babylonian astronomers looked to the skies nightly to discover their great wonders. They applied of mathematical principles on cosmic bodies together with the study of light through optics. Though it was the ancient Greek philosophers who would develop the earliest forms of rational theoretical science. Phoenician scholar Thales was the first to use natural explanations to explain phenomena, explaining that every event had a natural and explainable cause. Another major thinker of his time was Leucippus, who proposed the theory of the atom. He stated that if a block of cheese was cut and cut until it could be cut no more, the remaining particle would be what we now know as the atom. One of the great forefathers of science, Aristotle, founded a philosophy based on observation to infer general principles, then to make deductions from said principles for further observations – with the cycle forever continuing. He heavily emphasised empiricism - the theory that all knowledge is based on experience derived from the senses, sparking the start of the experimental process of science. The Arab physicist Ibn al-Haytham took prose from the works of Aristotle and began this practice experimental methods of data collection in his Book of Optics (1021). His combination of observations, experiments and rational arguments to support his theories on sight and vision through data collection from experimental practice was all together a new approach to learning. The work of the Persian scholars is still deeply rooted in modern science, astronomy and knowledge, and the milestones that they achieved were not superseded till much later in the west. #FlamePhotometer #ScientificMethod #Chemistry

Calcium is one of the most abundant minerals on earth – it’s the most common mineral in the human body and has a host of industrial uses. This silvery-white, soft metal is the fifth most abundant mineral in the Earth’s crust. It tarnishes rapidly in air, reacts with water and is the third most common metal after iron and aluminium. It is the main ingredient in limestone. Put simply, the world would be a very different place without it. Calcium in the human body Calcium is vital to the health of muscles, ease of digestion and the circulatory system. However, it is in building our bones and teeth for what calcium is best known and vital for. Calcium phosphate is the main component of bone and the average human contains about 1 kilogram of calcium. To promote bone growth, children and pregnant women are encouraged to eat foods rich in calcium, such as milk and dairy products, leafy green vegetables, fish and nuts and seeds. How calcium behaves Calcium is safe in its ionic form in the body, but it is highly reactive with water, forming hydrogen and calcium oxide. For this reason, metallic calcium must be stored in oil to avoid any moisture reacting with the calcium. The metal is also very soft, you could cut through it with a butter knife with ease - however it will rapidly oxidise, meaning it will lose its dull shine to a more grey/white color. How we use calcium Calcium has been used for generations in plaster, found as far back as 7000BC in models and sculptures and is still commonly used today for the exact same reasons. However, a metallic calcium sample was not isolated and identified until 1808 by the scientist Humphry Davy. In medicine, calcium is used for finding bone diseases such as osteoporosis, which results in a reduction in mineral content in the bones. The disease can also be treated with calcium supplements. Because it reacts strongly with Sulphur and oxygen, it is ideally used by the steel industry. These elements float to the top of molten steel and can be easily removed by combining with calcium, leaving the liquid steel behind. The aluminum industry also uses calcium to harden aluminum into an alloy. This process is effective because the large calcium atoms break up the soft structure of the aluminum. Calcium in the natural environment Calcium is not found in its ‘pure’ form in nature, but occurs abundantly as limestone (calcium carbonate), gypsum (calcium sulfate), fluorite (calcium fluoride) and apatite (calcium chloro- or fluoro-phosphate). Hard water contains dissolved calcium bicarbonate. When this filters through the ground and reaches a cave, it forms stalactites and stalagmites. Calcium metal is prepared commercially by heating lime with aluminum in a vacuum. #FlamePhotometer #Calcium #Chemistry

Analysis in chemistry often boils down to two key methods – Qualitative and Quantitative. Both have their pros, cons and different uses depending on the type of analysis required and how it will be applied. But what is the difference between the two? What is Qualitative analysis? Qualitative analysis comes down to a simple “Yes or no” answer. The test for hydrogen known as the ‘pop test’ is a good example, and one common in school classrooms. By holding a lit flame over the tip of a test tube, a small ‘pop’ would be heard if hydrogen is present, because it has combusted with oxygen present to form water. Either Hydrogen is present and a ‘pop’ is heard, or it is not present and no combustion occurs. It specifically looks at the physical qualities of the sample to give an answer. Other examples of Qualitative analysis testing: · Bromine test to identify double or triple bonds in a hydrocarbon chain. · Solid Sodium to test for alcohol functional groups. · Litmus paper tests for pH. What is quantitative analysis? Quantitative analysis specifically looks at the quantity of something in something else. Given we specialise in flame photometers, it seems only appropriate to give an example using one of our instruments. The Photometer is specifically designed to give you a reading of the quantity of different ions (Na, K, Ba, Li and Ca) in an aqueous solution. The entire process of photometry came from a metallurgist investigating the colour of a flame to see what metals were present in the ore, which resulted in chemists identifying that different elements gave off different coloured flames (for example Lithium giving off a classical brick red flame). This is common in history, where a qualitative analysis starts the trail of knowledge from a qualitative analysis all the way down to a modern-day quantitative analysis of a material, which is then further and further improved upon to give more precise and accurate results. More examples of Quantitative analysis testing: · Gas and liquid Chromatography with a Mass Spectroscopy analyzer. · A Flame Photometer. · Titrations. · Bomb calorimeter. · Fourier Transform Infrared Spectrometry. You can read more on the history of the flame photometer in these blog posts: https://www.bwbtech.com/post/l%C3%A9on-foucault-and-his-contribution-to-the-study-of-light https://www.bwbtech.com/post/who-invented-the-flame-photometer #FlamePhotometer #Chemistry #Flame

Barium, like all the other alkaline earth metals, is soft and silvery (however forms a very dark grey colour upon oxidation unlike most other alkaline metals), reacts with water violently and is not found in its elemental form in nature due to its high reactivity. However, it exhibits interesting properties, such as YBCO, a high-temperature superconductor which was one of the first alloys to exhibit these properties. In photometry, the flame colour of Barium is green and does not have many spectral overlaps with other ions that a flame photometer analyses routinely making its analysis simple and easy. Electronically Barium is found in the 2+ state in pretty much every case that you can think of apart from rare and unstable cases it is found in the +1 state such as Barium Fluoride gas, which is very unstable. Barium discovery is interesting due to it being commonplace to use it during alchemy. Rocks that washed up on the beaches of southern Italy due to a large amount of volcanic rock found there. It had been used for around 170 years before in 1774 it was thought to contain new element humanity had never isolated before. Multiple attempts were made to isolate barium, however, due to it being strongly bound to oxygen, the closest that they got to isolating it was Barium Oxide. It was Humphry Davey who initially isolated the element via molten electrolysis of barium salts. Other claims to fame that barium has is that Barium Sulphate was the very first thing to be used to develop x-rays the digestive tract in 1908. Barium production is usually done from Baryte rocks, which are commonly found in England, China, Romania and also most of the former USSR. However, only 8% of all baryte mined in modern times is used to make Barium and it is found in low concentrations in both seawater as well as the outer crust of the earth. Barium in commercial use, however, is limited. It was used as a way to ensure that residual gasses from vacuum tubes are removed, as barium sulphate is highly reactive to most gasses found in the earth atmosphere, Oxygen, CO2, Water and Nitrogen. It also exhibits properties that can trap noble gasses. However, as the commercial use of vacuum tubes has died with the rise in LCD screen displays, barium is not commonly found in day to day commercial locations. #Barium #Flamephotometer #greenemission #elementalanalysis

When running a Flame Photometer you want to ensure that not only are you achieving the most accurate possible results but also the most cost efficient use of power and consumables, at BWB we have Flame Photometers that run at some of the best prices available per sample. Here are a few in-depth stats to really show you how much you can save with a BWB Flame Photometer. Cost per sample when in operation Assuming the instrument is pre-warmed and calibrated then the cost per sample of both electricity and gas is that of £0.000524527037 Cost per sample from cold Assuming the instrument needs warming and calibrating using a single point calibration standard, then the electricity and gas cost per sample is then £0.008392592593 which allows for 16 minutes of operation. So lets take a look at running costs per minute ignoring samples and other variables. The LPG(per minute) cost is at £0.000364537037 This is calculated from a cost of £0.635 per litre of compressed liquid propane, yet our Flame Photometers run on gas, not the compressed liquid so this is expanded at a ratio of 1:270 (the compression factor for liquid propane gas (LPG)). The range of BWB Flame Photometers have a consumption rate of 0.155L/min (gas). Electricity (per minute) £0.00016 This works out with £0.16 per Kwh, the consumption of a BWB Flame Photometer being 61watts/hour. Cost per minute of operation = £0.0016 So how does this compare to other technologies? ICP comparison: ICP-MS: ICP-MS also takes about 3 min to carry out a duplicate analysis for 10 analytes, which is equivalent to 20,000 samples per year. Based on an annual operating cost of $13,250, this equates to $0.66 per sample. Using ICP in your lab for the routine analysis of Na, K, Li, Ca or Ba? Why not get in touch with one of our experts to see how we can help your lab save money! References: Cost analysis: https://www.globalpetrolprices.com/ (based on UK prices Oct 2019) https://www.labmate-online.com/article/mass-spectrometry-and-spectroscopy/41/scientific-solutions/money-to-burn-do-you-know-what-is-costs-to-run-your-atomic-spectroscopy-instrumentation/2030

Here at BWB Technologies we are delighted to have been awarded ISO 9001:2015 certification, an internationally recognised standard that ensures their products and services meet the needs of customers through an effective quality management system. A Continuous Improvement Culture BWB’s decision to work towards ISO 9001:2015 accreditation demonstrates our commitment to continually improving our products and services. To become ISO 9001:2015 compliant, the dedicated BWB team who are based in Newbury, UK, underwent an extensive company-wide audit that included quality management system development, a management system documentation review, preliminary audit and initial assessment. Relentless Focus on Excellence ISO is one of the most rigorous and well-regarded standards in the world. The BWB team were audited by QMS, and were presented with their certificate in April 2019. Gaining ISO 9001:2015 reinforces BWB’s relentless focus on creating industry-leading products and services, measured against global benchmarks of industry excellence. General Manager, Hozan Edwards said: “Achieving ISO 9001:2015 certification is fantastic news and means our distributors, customers and partners have complete assurance in our products and enables the company to continue to operate to the highest quality standard.” He adds: "I am extremely proud of the hard-work everyone from the team has dedicated to the business for this achievement, which proves theirs and the company’s commitment to ensuring quality and providing the best possible service to our ever expanding client base. BWB are dedicated to our continual improvement and development plan, in achieving and maintaining an ISO 9001:2015 accreditation ensures we have the processes and systems in place for this to continue long into the future." #BWBTech #FlamePhotometery #ISO9001 #Chemistry #Lab #Science

The Big Breakthrough Into Spectrometry. Jean Bernard Léon Foucault was born in 1819 as the son of a book publisher. He was mostly homeschooled and then went to study medicine. However due to a phobia of blood he quit this path and took an interest in the development of existing practical methodology in photography and photo development. This took him into microscopic photography where he started his journey into science as an experimental assistant in taking photos of microscopic anatomy. It was during his time as an assistant that he chanced upon someone studying light waves. They took a primary look at the comparison between the light of the sun and a carbon arc lamp and the lime in an oxyhydrogen flame. Going back to our last post, he also took from Herschel’s work and studied the interference of infrared radiation in this light. One of the first experiments into his contribution with spectrometry was done by Foucault in 1849 where he experimentally demonstrated absorption and emission lines of a flame appearing at the same wavelength. You may notice that these terms are still in used today in the flame photometer and many other spectrometers as being classed as emission and absorption spectrometers. He also critically noted that the difference between these emission lines were from the temperature of the light source. Whilst his early days were based in measuring light and its spectrum, he then went on to analyse more physical constants. He made the first reasonably accurate measurement of the speed of light, and this was considered by the scientific community to put to rest Isaac Newtons theory of corpuscular theory of light, which we will touch on next week when looking at the work done by Isaac Newton. His experiment was done by having a beam of light shine into a rotating mirror, then through a lens and onto a stationary mirror. The time taken to bounce the beam of light back to the rotated mirror would result in the return angle of the light being picked up in a new direction, and then by measuring the angle of the lights path changing the speed can be measured. However, this is not anyway near close to the accuracy on the speed of light measurements we have today. He thought the speed of light to be 298,000km/s only 10,000km/s from out currently accepted speed of light (a 0.6% margin in error). Foucault went on with his study of physics and invented the gyroscope. A device that was later installed into planes for navigation, still finding a use for it over 100 years later. He also had an interest in lenses and invented a test to look at the curvature of a lens or mirror. Later in his life he discovered how to polarize light, which was initially used so that people can look at the sun without damaging their eyes, however he did not understand the mechanism behind this phenomenon. In 1868 he died to multiple sclerosis and his name is now inscribed on the Eiffel tower. We at BWB Tech are glad for Foucault’s study into light, and it was his base theory that prompted our work here to begin in the first place. #Spectrometry #leonfoucault #flamespectrometer #flamespectrometry

How an astronomer discovered the link from the stars to the properties light itself. William Herschel was born in Hanover, part of the Holy Roman Empire on the 15th of November 1738. Initially he started his career in a military band, however at the age of 19 he migrated to Great Britain after the Hanoverian Guards were defeated by the French in the Seven years war. Upon arrival to England he played music and composed 24 symphonies, which are still heard today. However, his true fame lies in astronomy. Reading into natural philosophy and engaging with the 18th century Philomath’s of the time, his intellectual prowess grew rapidly. He read books by Robert Smith, William Emerson and Sir Isaac Newton which prompted him to build his first telescope due to the influence they had on him, a replica of which is in his museum in Bath, England. He took to looking at the stars in 1773 and by 1774 he discovered the rings of Saturn and the Great Orion Nebula. The first ever written account of the rings of Saturn was by Herschel, which he described as the planet having “ears”. Later in his astronomy career he also discovered 4 moons as well as Uranus. Later in his life after delving into astronomy further in 1800 he was testing filters for the sun so that he could observe sunspots through a telescope. Taken from his past interest in Newtons works, he was using a prism to split a beam of light from the sun. Holding a thermometer out from the red end of the spectrum he discovered that there was an increase in temperature in comparison to the visible light spectrum. He had discovered infrared radiation from the sun, and gave birth to the study of spectrometry and wavelengths outside of the visible spectrum. He initially explained this phenomenon as “calorific rays” from the Latin heat. This discovery boosted further scientists to analyse the light spectrum which had stagnated for a time. This study of invisible light waves has given us a huge understanding of light, from gamma rays to the commonly used X-ray in hospitals. Without Herschel’s push in the study of the light spectrum, it’s easy to imagine that spectrometry would have slowed and we would be behind where we are today. In the study of flame photometers, his work is referenced in further works from other scientists touched on in our previous blog post. We will continue down this track and give a more in depth look at the forefathers of the BWB Flame Photometer. #williamherschel #historyofflamephotometer #historyofflamephotometry

How flame temperature affects your samples. We have written about the mechanism of photon emission from Ions in a previous segment, however, we wanted to give this grounding and show how it is effected by physical parameters that you can control, here’s a quick refresher. The process of excitation is a constant “flickering” effect where the ion is excited and relaxed. During the excitation stage the ion takes in ambient energy to promote the ion to a higher energy state and then at relaxation the ion releases the energy as a photon of light equivalent to the drop in energy states. The temperature of the flame is essential to promote the excitation of the ions and therefore emit a photon; this is where the energy for the excitation process comes from. As flame temperature is increased, it is not that the emission of the single photon is given a more energy from the flame, or the electron is excited to a higher energy state than a lower one. This is because atoms and ions have set energy states that they can achieve. Therefore, the intensity of the flame emission is not a “larger” jump but a higher ratio of ions that are in the excited state compared to the relaxed state thus resulting in a greater quantity of the relaxation process emitting more photons for the photodiode to detect. In short – a hotter flame means greater emission spectra. An increase in flame temperature can also help reduce contaminants and interfering species that alter the ion’s energy quantum levels and therefore the wavelength of emission. Let’s look at Calcium Phosphate for example. Calcium Phosphate is known to give a much lower reading of calcium in a sample, however, is very strongly bonded together. The energy given from a standard air and propane flame is not sufficient to break the Calcium to Phosphate ionic bond. Let’s say theoretically we were to use a mixture of an oxidiser and acetylene gas, this would burn at a much greater temperature and would break the ionic bond and eliminate the reduction of the emission caused by the phosphate interference. Other suitable means of increasing flame temperature whilst using an air and propane flame are through the introduction of organic solvents which burn in the flame and boost the flame temperature. This is a huge reason why matrix correction in samples is vital. Having a sample of wine and not treating your standards with the same % of alcohol that is found in the wine would result in the flame temperature being higher in the sample than that of the standards. Hopefully having read through this you’ll now have an understanding as to why this would impact on the accuracy of results obtained. For further information on matrix solutions or application specific advice please get in touch with the BWB team who will be more than happy to help - Contact Us. #flamephotometryandtemperature #temperatureofflamephotometer #flametermperature

From 1500 to modern day, a brief history of the flame photometer In our previous blog posts we introduced the concept of how the excitation of electrons results in the emission of a photon; however, it took a long time for this concept to take shape. Prior to the knowledge of photons and electrons a German metallurgist named Georgius Agricola commented on “the colour of fumes” from different types of ores, and how to identify them in the introduction of a paper in 1556. This was a qualitative analysis of the colour of a flame to determine what was contained within the ore. This concept however, was then not touched upon for two centuries until Isaac Newton began to investigate light and its properties in early 1700. Then not for a further century when the beginning of investigations into spectral lines of the rays of light from the sun was investigated in the 1800s. Hershal studied the emissions of an alcohol lamp in 1823, which is the first example of a lamp being studied for its light emission. We now have had the two major components of a flame photometer studied yet, there were 3 centuries between them and no link had been formed. Soon after however, would result in an explosion of activity between the flame and an element. Foucalt was the first to make the link between Sodium emissions on a lamp and the Sodium emissions from the sun. However, it would be Kirchoff who would make the major breakthrough in the topic stating that “the relation between the powers of emission and the powers of absorption for rays of the same wavelength is constant for all bodies at the same temperature." Kirchoff and Bunsen (Inventor of the Bunsen burner) collaborated together and are now credited with the founding of analytical spectrometry, the discovery of indium gallium and thallium are credited to chemists of the time via this technique of flame excitation. In 1873, Champion, Pellet, and Grenier TM produced an instrument that was suggested three years earlier by Janssen to quantize the analysis for sodium. They used a spectroscope, with visual photometry, to measure sodium emission. Two flames were used, one for the unknown, the other for a series of standards. The spectra were displaced so they could be observed simultaneously. The authors reported an accuracy of two to five percent for sodium in plant ash. Their system was the first instrument specifically designed and constructed to make possible quantitative data using flame excitation. Apparently little attention was paid to the method used to introduce the sample into the flame until 1877 when Gouy LG demonstrated conclusively that radiation intensity from a flame was a function of flame size and the quantity of substance introduced into the flame. To control those factors Gouy designed a pneumatic atomizer to inject a controlled amount of sample into the flame. The result was increased precision and accuracy of analysis. In 1873, Champion, Pellet, and Grenier developed an instrument that analysed the content of sodium in plant ash samples to a within 5%, which would be the “invention” of the flame photometer as we see it today. Now BWB Technologies are on the cutting edge of flame photometers in the modern world and pride ourselves in trying to further push the boundaries of what is possible with them as well as streamlining current processes and reducing operation burden. #whoinventedtheflamephotometer #flamephotometerinventor

A Brief Guide To The Inner Workings of a Flame Photometer. A Flame Photometer is made up of what is primarily a main column of working parts supported by electrical control chips for the operation of the unit. A simple flame photometer consists of the following basic components: 1. A flame that can be maintained in a constant form and at a constant temperature: “The Burner”. 2. A means of transporting a homogeneous solution into the flame at a steady rate: “Nebuliser and mixing chamber”. 3. A means of isolating light of the wavelength to be measured from that of extraneous emissions: “Simple colour filters” (interference type). 4. A means of measuring the intensity of radiation emitted by the flame: “Photo detector”. First we must overcome the difficulty in introducing the sample to the flame in a consistent and effective manner. For this a nebuliser is utilised. The nebuliser is a small bore needle in which a liquid sample is consumed by a jacket of high pressure air passed around it. This causes the liquid sample to be not only be drawn up from the sample pot using the basis of venturi but also atomised into a fine mist when passed through a small orifice at the end of the device. The process of obtaining a fine mist is quintessential to the accuracy of the instrument and is the heart of the instruments repeatability, accuracy and stability. Here at BWB Technologies we have invested hundreds of man hours and thousands of pounds in order to design one of the best nebulisers on the market. After sample atomisation the sample passes into the mixing chamber; here the fuel gas is typically mixed into the sample mist. Again the design of the air flow within the mixing chamber is another area of paramount importance to generate results within tight specifications. A cyclone action is utilised to thoroughly mix the gases which avoid causing hot spots of higher fuel concentrations in the mixture, as these would cause greater and random emissions in the flame, thus affecting stability and repeatability. The design of the BWB Technologies mixing chamber stems back to our company foundation in 2005 and now leads the market in its construction, chemical resistance and operation. The Burner head finally combines the mixture of gas, air and vapour sample into an emission spectra from a flame burning at approximately 1900°C. The burner assembly is another area of great design work, as it must not only warm up rapidly and maintain a constant temperature but also ensure that velocities and burn rate are such that blow back of the flame cannot occur, for operational safety. Most instruments include a viewing port allowing the operator to observe the flame conditions and set the height of flame. The BWB Technologies burner assembly is constructed from high performance grade stainless steel and expertly machined to high tolerances using CNC lathes. This ensures that every burner performs to our high standard. The Sensor array is a collection of photodiodes. These photodiodes are what turn the physical light emission into a pulse of electrical energy which can then be processed by the instrument. Photodiodes however, cover a large range of wavelengths and so to ensure only the required wavelength is collected they are typically installed behind an inference filter. The interference filter is produced to only allow a specific range of light to pass through. Through research and experimentation BWB Technologies have put in place a set of design parameters which set our diodes to specific wavelengths to pick up samples of light emission with minimal spectral overlap between different ions spectral emissions. Once the light has been converted to an electrical signal it needs displaying in a form appropriate for user interpretation. Typically analogue instruments convert the electrical signal into a number based on intensity. Older flame photometers then display this number for the operator to plot up on their own calibration curve, whereas other instruments may display the number as a concentration relative to a calibration curve pre-generated. However, the BWB Technologies’ range of flame photometers are microprocessor controlled. The BWB XP Plus instrument allows the operator to produce self-defined calibration curves across the 4 detectable elements with up to 10 points of calibration per Ion. Furthermore, the 4 elements can all be calibrated simultaneously using multi Ion calibration standards thus drastically reducing operation time. The employment of microprocessor technology allows the XP Plus to adjust the calibration curve automatically making allowances for changes in atmospheric conditions or sample temperatures through the use of an internal standard (Internal reference). In the XP Plus instrument this can be Lithium or the fifth channel of operation, Caesium. For more information on the range of BWB Technologies Flame Photometers please Contact Us. Alternatively, further information on the XP Plus Instrument can be found by following the XP Plus Instrument Link.

Increase your sample throughput with automation. Lab managers are constantly seeking solutions to tackle the problem that emerges with any type of analysis based instrumentation. By their very nature such instruments demand the constant attention of operators in order to dilute, calibrate and analyse each and every sample. This can take many hours of manpower, which of course costs a lot of money and prevents your operators and analysts from actually analysing their data and spending greater amounts of time on research. Consistent and careful preparation of a sample manually can take anywhere between 5-10 minutes when dilutions and internal references must be conducted and or added. With labs running a high number of samples a day, costs can quickly rise through operators sample preparation time. Enter the BWB Automatic Fluid Handling system, or AFHS for short. An auto sampler designed and built specifically for linking with your flame photometer drastically reducing sample preparation time and increasing throughput. The AFHS can offer up to an 80% reduction in sample preparation and analysis time. Now just imagine the amount of time saved that analysing over 100 samples a day could do for you, your business and your research. When combined with the BWB range of Flame Photometers the BWB AFHS even has the ability to run multi ion calibrations during a single run, meaning that you can run multiple different types or concentrations of samples without having to recalibrate for each ion of interest. Auto samplers are often known for being able to dilute their samples into a range of concentrations during the automatic sampling process and the BWB AFHS is no different. Automatic operator configured dilutions can be carried out within a wide 1:6 to 1:100 range. Preventing wasting huge amounts of time in manually diluting each sample down to bring it within a measurable level; and remember, whilst all of this is going on, your analysts and operators are working on more important matters. As well as increasing sample throughput and the productivity of employees, the BWB AFHS also offers substantial gains in the precision and accuracy of sampling through the elimination of human dilution errors. The carefully designed mechanical dilution and calibration ensures that the exact same movements and quantities of diluents are added into your sample to ensure a very tightly coupled range of precise additions or dilutions to your samples and calibrators. The BWB AFHS offers a rotating carousel that can load over 89 samples and calibration standards at a time. The automated arm and sample cannula take samples from these vials to the sample introduction point for analysis as well as mixing the sample to ensure a consistency in sampling technique. So whilst you may convince yourself that there are many reasons as to why you may feel that the requirement of an automated system is not what you’re after, we hope that this gives you an insight into the reasons why the BWB AFHS is becoming more and more popular in the world of Flame Photometers. #autosampling #autosampler #flamephotometersampling

Flame Photometer maintenance is a vital part of making sure that readings and calibration curves are kept to the lowest inter-sample variance possible. A flame photometer requires maintenance as it is used. Parts suffer can suffer greatly dependent on the sample makeup, the age of the device and the conditions in which the device is kept. The two main parts which cause the most instability if not properly maintained, and are also the easiest to damage are the mixing chamber and the nebuliser. This could come in the form of either a nebuliser blockage or etching into the nebuliser, which would affect the finely tuned and calibrated spray from the nebuliser. Blockages would cause a pressure gradient in the nebuliser which would affect the spray pattern of the aerosol, whilst etching into the nebuliser would affect the final contact point of the spray needle, thus affecting the spray. To minimise blockages as standard BWB Technologies provides a finely calibrated cleaning rod to insert into the centre of the nebuliser needle to clean out any blockages. Blockages are caused by viscous material or particulate matter “gunking up” the needle and needing to be manually cleaned. Etching is caused by having a high acidic content which reacts very slowly with the steel of the nebuliser. Normally H2NO3 is the commonly used pre-treatment acid and the NO3 ion gives a degree of protection to the steel, however acids such as HCl and organic acids can cause etching at a faster rate. The mixing chamber is the other main factor which leads to varying readings due to lack of correct maintenance. It is in this component where the combustible fuel mixture and the sample spray from the nebuliser are introduced to each other and mixed. It contained a small disc (or baffle) split into 4 different slightly angled quarters as well as a large cavity. The placement of the nebuliser is also at an angle so to promote a tornado effect inside the cavity that passes through the small holes in the plastic disk. If not adequately cleaned when using a viscous material in the analysis, the viscosity can cause the sample to form small particulate matter to form on the inner surfaces of the mixing chamber and baffle. This can then get picked back up by the tornado effect when the sample or calibration standard is changed, which causes a sudden spike in the sample concentration, therefore reducing the stability of the reading. To clean your mixing chamber, it is usually recommended that an ultra-sonic bath is used to dislodge large particulate matter. DI water mixed with the BWB Technologies recommended cleaning agent forms the base solution for the ultrasonic bath. A rinse of DI water is then used to wash out the mixing chamber and baffle. Always make sure to put back the rubber O-Ring to ensure is it air and water tight, push the baffle into the lower section of the mixing chamber and make sure it is not poking out over the tips of the lower section and flush with the surface, care should be taken to ensure it is replaced in the same orientation and aligned with the drain slots, finally screw the mixing chamber up. The mixing chamber rarely reacts with other materials and solutions due to being made of highly inert polymers; however the above method should be an effective way of cleaning the mixing chamber. #howtomaintainaflamephotometer #flamephotometermaintenance #maintainflamephotometer

The method by which photometers operate is as follows. The fundamental property which makes all photometry viable is due to the excitation and relaxing of electrons within the ion. In all flame photometers the reason as to why there is a heat source is so that the ions in the sample can gain sufficient energy to excite the electrons present in them. Excitation is defined as when an electron bound to a nucleus goes from its ground energy state to a higher energy state. However a common misconception with excitation is that the electron itself is not excited, the entirety of the atom or ion is excited as the individual electron is still just an electron and it is excited due to its difference in energy to the ground state of the other electrons in the atom or ion. In accordance to the first law of thermodynamics, energy cannot be created of destroyed; therefore when an atom is excited and relaxes back to its ground state, the energy stored in the excitation of the atom to a higher state must be released and transformed into another form of energy. This energy is emitted as a photon, and the frequency of the photon is proportional to the amount of energy lost in the drop between the excited state and the ground state. Now that we understand how the frequency of the photon emission is formed, measuring the photons emitted comes down to either an emission photometer or an absorption photometer. An emission photometer, commonly known as AES (atomic emission spectroscopy) measures the emission of photons off of the sample with the use of photodiodes to detect their intensity and from that their concentration in the sample. A second type of photometer uses AAS (atomic absorption spectroscopy). This is where a light source is pointed through the flame of a photometer and into the diodes and a baseline of the light source is recorded. Then when a sample of ions is introduced to the flame the specific wavelengths of the light source is either absorbed by the sample or allowed to pass through to the diodes. As there is a quantifiable drop in the wavelength of light absorbed by the diodes can be detected, this can then be calculated to a specific concentration (as explained in the previous blog post). Whilst the terms AES and AAS are common in the photometer world, they can also be related to ICP (inductively coupled plasma) such as ICP-AES. The naming format in chemical analysis can often help you easily understand what the instrument is and what it does once understood. Let’s look at FP-AAS for an easy example the FP in relation to Flame Photometer, and the AAS as atomic absorption spectroscopy. In spectrometry the prefix of the abbreviation is method by which the atom is excited and the suffix is the method by it is detected. Whilst ICP and its many forms are useful, they require a lot of work to use. Flame Photometry on the other hand is very simple to start up and get running with minimal training and high sample throughput. The initial cost difference between purchasing an ICP unit in comparison to a Flame Photometer can be huge, with most Flame Photometer units coming to under £10,000 and most ICP units being a minimum of 10,000 for a low spec model. #principlesofflamephotometry #flamephotometryprinciples

Flame Photometry isn’t only used for Chemists. But how is Flame Photometry used in Biology and Medicine? Flame Photometers are typically thought of for analysis of water samples to determine their ionic content, however a large proportion of flame photometers in today’s market are used to analyse biological samples. For Biologists this may include plant samples, where a measured difference of ion content between the same species could be measured in different locations. It could also be used to track ion content in animals to detect how the environmental factors play into these readings. For medical usage, the two main sample types are either blood (serum or plasma) or urine. Urine can track diet problems as well as track unexpected rises in urine salt levels which could be indicative of further complications. Blood and serum samples are very useful to be tracked as salt levels in the blood supports blood pressure. Typical Sodium levels found in the blood is between 135 and 145mEq/L and is easily tracked with the use of a flame photometer. If this level falls below this it is known as the condition Hyponatremia and the opposite being high salt levels resulting in Hypernatremia. Measuring Lithium and Potassium levels in blood samples is vitally important as these are the reason why our nervous system works, via forming a voltage deficiency across a cell membrane which enables contraction of muscles. Abnormally low or high concentrations of these vital metabolites can cause muscle spasms. Photometry in itself is useful for these tasks as the speed at which samples can be taken and measured, especially when paired with an automatic fluid handling system (AFHS) for faster sample throughput. Being such a cheap yet effective alternative for sample analysis it has found its way into many different subject areas. The ions that a flame photometer can measure are Sodium, Lithium, Potassium, Calcium and Barium. These ions are commonplace within biological systems as well as their availability for consumption in aquatic environments, which further emphasises the usefulness of a flame photometer. #flamephotometeruses #flamephotometeruse