Methods For The Determination Of Heavy Metals In Cocoa

Methods For The Determination Of Heavy Metals In Cocoa

Much of today’s cocoa comes from developing countries, such as Ivory Coast, Indonesia and Nigeria. Since many of these countries have no or only a few enforced environmental pollutants such as lead and other heavy metals can accumulate in cocoa and contaminate foods made from it. Several methods can be used for the determination of heavy metals in the cocoa powder so they can be eliminated before the cocoa when the consumer.
Trace Metal Clean Technique
To use the trace metal clean technique, a clean room, or “bubble”, is required. The bubble can be created in a room and can be partitioned off with plastic. All metal must be removed from the room or hot or it must be covered up with tape. A ventilation system in clean air filtered through a large HEPA filter, which filters out any metal particles which are already in the air. Inside the clean room, the glass or plastic containers for cocoa powder and then washed with ultrapure water and air-dried, so no metal particles will follow them. In clean rooms, various methods determine heavy metals in cocoa can then be used without fear of infection.
Aqua Regia Digestion
“Aqua regia” consists of a quantity of concentrated nitric acid are mixed with 3 to 4 volumes of concentrated hydrochloric acid. It is so corrosive that it readily dissolves gold and platinum. Because of toxic smoke, aqua regia digestion made under a fume hood. A sample of cocoa is inserted in a plastic or glass container, mixed with the right amount of aqua regia and then gently heated in a water bath. A predetermined amount of the solution is then taken out and put in a test tube, where it is mixed with an organic solvent and gently shaken. This solvent collects some heavy metals in solution. This process can also be done in a microwave instead of hot water.
Inductively coupled plasma mass spectrometry (ICP-MS)
In Inductively coupled plasma mass spectrometry (ICP-MS), an cocoa selection is transformed into an aerosol, which is then ionized with high temperature argon plasma, that wraps it into neutral elements. This ionizes the sample. The sample is then analyzed with a mass discriminate and detector. The analysis is based on mass-to-charge ratios of ionized samples. This process is an efficient and accurate way to determine the presence of heavy metals in a variety of foods, including cocoa. It is the most widely used method for determining the heavy metal content in food and is FDA approved.

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