How to determine lead in food?

Food safety has a huge impact on our health. If the lead content in food exceeds the standard, it may cause lead poisoning in the body after consumption. Therefore, determining the lead content in food is also one of the ways to determine food safety.

1. Common detection methods for lead in food

Graphite furnace atomic absorption spectrometry, its atomizer is a graphite furnace atomizer, which places the sample on the graphite tube wall, graphite platform, carbon rod sample hole or graphite crucible and heats it to high temperature electrically to achieve atomization, and its detection limit is Sug/kg. Flame atomic absorption spectrometry, which uses a flame atomizer, which consists of a sprayer, a premixing chamber, and a burner, and has a detection limit of 0.1 mg/kg.

Single sweep polarography is a potential-controlled polarography method in which the electrode potential is a linear function of time. Because an oscilloscope is used to observe the current-potential curve, it is also called linear variable oscillographic polarography. The detection limit of this method is 0.085 mg/kg.

Disulfide hydrazone colorimetric method: This method uses disulfide hydrazone as a color developer and determines the content of the component to be tested by comparing or measuring the color depth of the solution. The detection limit is 0.25 mg/kg.

Hydride atomic fluorescence spectrometry, atomic fluorescence spectrometry is a spectral analysis technology between atomic emission spectroscopy and atomic absorption spectroscopy. Its basic principle is that ground state atoms (usually vapor state) absorb radiation of appropriate specific frequency and are excited to a high energy state. Then, the excited state atoms emit fluorescence of characteristic wavelength in the form of light radiation during the de-excitation process. Because hydrides can be well atomized in an argon-hydrogen flame, and the argon-hydrogen flame itself has a high fluorescence efficiency and a low background, the combination of these factors enables a good detection limit to be obtained using a simple instrument, and its detection limit is Sug/kg.

2. Commonly used detection methods for cadmium in food

The detection limit of graphite furnace atomic absorption spectrometry is 0.lug/kg; the detection limit of flame atomic absorption spectrometry is 5ug/kg; the detection limit of colorimetry is 50ug/kg; and the detection limit of atomic fluorescence spectrometry is 1.2ug/kg.

3. Commonly used detection methods for total mercury in food

The detection limit of atomic fluorescence spectrometry is 0.15ug/kgc21J; the detection limit of disulfide colorimetry is 25ug/kg.

The analysis of methylmercury is usually carried out by acid extraction, mercapto cotton adsorption and separation, and then by gas chromatography or cold atomic absorption spectrometry.