[Determination of inorganic arsenic in rice by liquid chromatography-atomic fluorescence spectrometry].

OBJECTIVE

To develop a method for the determination of inorganic arsenic (As(i)) in rice and to provide the basis for revising the national standard method GB/T 5009.11 "Determination of Inorganic Arsenic in Food". To compare the extracting ability of trifluoroacetic acid (TFA) under different concentrations and the different time for extracting samples. To evaluate the pollution of rice sampling from different original production places.

METHODS

Inorganic arsenic of rice was extracted under heating at 80tC by trifluoroacetic acid. The supernatant was concentrated to dryness by centrifuging, and then dissolved in the solution for mobile phase by ultrasonication. Passed through RP cartridge and filter, the sample solutions were ready for analysis. The mobile phases were 1 mmol/L NH4H2PO4 solution and 20 mmol/L NH4H2PO4 solution. As were separated with an anion exchange column, Hamilton PRPX-100, and detected by liquid chromatography-atomic fluorescence spectrometry (LC-AFS).

RESULTS

Extraction with 3% TFA (v/v) and heating for 2 h were desirable for the pre-treatment of samples. The results meet the reference value of As.

CONCLUSION

This method is suitable for the analysis of inorganic arsenic in rice. The inorganic arsenic content of samples collected from original production places did not exceed the limit standard.