Comparison of on-site field measured inorganic arsenic in rice with laboratory measurements using a field deployable method: Method validation

Abstract

A commercial arsenic field kit designed to measure inorganic arsenic (iAs) in water was modified into a field deployable method (FDM) to measure iAs in rice. While the method has been validated to give precise and accurate results in the laboratory, its on-site field performance has not been evaluated. This study was designed to test the method on-site in Malawi in order to evaluate its accuracy and precision in determination of iAs on-site by comparing with a validated reference method and giving original data on inorganic arsenic in Malawian rice and rice-based products. The method was validated by using the established laboratory-based HPLC-ICPMS. Statistical tests indicated there were no significant differences between on-site and laboratory iAs measurements determined using the FDM (p = 0.263, ά = 0.05) and between on-site measurements and measurements determined using HPLC-ICP-MS (p = 0.299, ά = 0.05). This method allows quick (within 1 h) and efficient screening of rice containing iAs concentrations on-site.

Keywords: Arsenic(III) (PubChem CID: 104734), Arsenic(V) (PubChem CID: 104737); Arsenic, (Arsenic-75) (PubChem CID: 5359596); Arsines (PubChem CID: 68978); Dimethylarsinous acid (PubChem CID: 185792); Field deployable method; Inorganic arsenic; Laboratory; Maximum contaminant limit; Mercury bromide (HgBr2), Mercuric dibromide (PubChem CID: 24612); Monomethylarsonous acid (PubChem CID: 161491); Nitric acid (HNO3) (PubChem CID: 944).; Onsite; Rice, arsenic; sodium borohydride (NaBH4) (PubChem CID: 4311764); sulfamic acid (PubChem CID: 5987).