Measurement of Potassium and Sodium in Wine
Wine is of particular interest nutritionally because it is typically low in sodium and relatively high in potassium.
Sodium is the predominant cation in breakfast cereals, at levels reaching 8mg/g. Potassium and calcium also vary, particularly in wheat-based products and those enriched with milk products or calcium salts.
Few wines contain over 200 mg/l of sodium and most contain less than 100 mg/l. Most wines contain between 500 mg/l and 1300 mg/l potassium. Red wines generally contain more potassium than white or rosé.
The sodium content is also lower in white and rosé wines. The daily requirement for sodium is between 0.5 - 2.0g and between 2 – 4g of potassium.
Samples are stored in clean screw cap vials which are completely filled, in order to prevent growth of aerobic organisms. The vials are stored at 4ºC until analysed.
The wine samples were diluted with deionised distilled water following a 1 to 200 dilution ratio. The diluted samples were stored in plastic containers prior to analysis.
It is recommended that prior to sample analysis for the use of data collection as well as standard dilution, a single point calibration and sample test is carried out so that the estimated range of results for samples can be used when considering the range of concentrations of the standards.
Preparation of Standard Graph
Set the flame photometer in accordance to MultiPoint/Single Ion Calibration found on page 24 of the BWB Technologies Installation and Operation Manual, to measure potassium emission. Nebulise the working standard solutions and adjust the controls until steady zero and maximum readings are obtained. Nebulise the intermediate working standard solutions and construct a graph relating raw emission data (known as RAW in BWB the flame photometer) to concentration of all the standard solutions.
Potassium and Sodium Content of Wine