Portable heavy metal analyzerThe detection methods mainly include the following:

1. X-ray fluorescence spectroscopy (XRF)

Principle: X-ray photons irradiate the sample, exciting the inner layer electrons of the atoms in the sample. When the outer layer electrons transition, secondary X-rays (fluorescence) are released, and their wavelength and intensity are related to the type and content of the elements. By measuring fluorescence characteristics, qualitative and quantitative analysis of heavy metal elements can be achieved.

Features: No need for chemical reagents, no consumables, no wastewater or exhaust emissions, suitable for rapid on-site testing, but slightly lower accuracy than laboratory methods. It can detect more than 20 elements including cadmium (Cd), mercury (Hg), lead (Pb), arsenic (As), chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), etc. Some instruments have a detection limit as low as 0.16mg/kg.

2. Anodic stripping voltammetry

Principle: Through electrolysis, heavy metal ions are reduced to metal on the electrode and dissolved into the electrode, and then the concentration of heavy metal ions is determined based on the magnitude of the dissolution current.

Features: High sensitivity for detecting certain specific heavy metals, suitable for rapid on-site screening.

3. Wet digestion method combined with photometric colorimetric method

Principle: After wet digestion of the sample, all forms of heavy metals are converted into ionic forms. After adding relevant detection reagents, color development occurs. Within a certain concentration range, the depth of the solution color is proportional to the content of heavy metals, following Lambert Beer's law. The content value is then determined by instruments.

Characteristics: The operation is relatively simple, but chemical reagents are required, which may generate waste liquid. It is suitable for on-site screening with low precision requirements.

4. Laser induced plasma spectroscopy (LIBS)

Principle: High power laser acts on the surface of the sample to generate laser-induced plasma, and the composition is determined by detecting the atomic and ion spectral lines in the plasma.

Features: Fast detection speed, but high equipment cost and low popularity.

These methods each have their own advantages and disadvantages, and are suitable for different detection scenarios and requirements. In practical applications, appropriate detection methods should be selected based on factors such as the properties of the sample to be tested, detection accuracy requirements, and on-site conditions. At the same time, to ensure the accuracy and reliability of the test results, attention should also be paid to key aspects such as instrument calibration, reagent storage and use, sample collection and processing.