Determination of Sulfur Contents and Heavy Metals in Soft Drinks

The soft drink and beverage industry implements stringent guidelines on the quality of carbon dioxide utilized in products for human consumption. In this industry, carbon dioxide (CO2) is basically produced with 99.9% purity, from the natural gas, which in return contains impurities such as mercaptans. Therefore bottled carbon dioxide (CO2) can sometimes contain these impurities. The most common impurities are ethyl mercaptan, methyl mercaptan and hydrogen sulfide. These organo sulfur compounds are odorous and can cause tainting to product. On the other hand the sulfur impurities can modify and impact shelf life and future value. Therefore in this study, the type and level of these compounds has been determined using a GC technique which seems to be less than 2 ppm and compared with the standard levels. On the other hand the quality of soft drinks has been controlled in terms of heavy metal compounds such as lead, cadmium, copper and zinc using atomic absorption techniques. The study revealed that the level of these impurities would be less than 0.45, 0.028, 0.077 and 0.018 ppm for lead, cadmium, copper and zinc, respectively and compared with the standard levels. Finally the acidity, total hardness and total dissolved solids (TDS) has been controlled and determined for the quality of the products.