An analysis of the potassium concentrations of soft drinks by HPGe gamma spectrometry

Abstract

Potassium, in a variety of compounds, occurs in abundance in the Earth’s crust, and is an essential nutrient for human health. A naturally occurring radioactive isotope of potassium, ⁴⁰K, is found in the food and water that we consume. This paper presents the results of a gamma spectrometry analysis of the ⁴⁰K concentrations of a selection of commercial soft drinks. The ⁴⁰K concentrations are used to calculate the overall potassium concentrations. The analysis was carried out using a hyper-pure germanium (HPGe) detector with Ortec^® ASPEC-927 multichannel analyzer module and GammaVision^® software. This system was chosen for its high resolution and automatic data processing. The carbonated soft drinks (sodas) Coca-Cola^®, Coca-Cola Light^® (sold as Diet Coke^® in the USA and other countries), Coca-Cola Zero^®, Pepsi^®, Pepsi Light^®, Pepsi Max^®, Big Cola^®, Lulu-Cola^®, Manzana Lift^®, Sprite^® and Fanta^® and the mineral waters Ciel^® and Peñafiel^® were analyzed. These brands are all international registered trademarks. The products analyzed were manufactured and bottled in Mexico. The results show a great variety of potassium concentrations in the different soft drinks analyzed (from 128.0 to 1113.1 mg/L). The concentration of potassium in the sodas, in conjunction with the amounts drank by one person in a year (180 L/year), are high enough to warrant consideration by public health authorities and by people to whom high potassium intakes pose a risk.