Arsenic speciation in rice by capillary electrophoresis/inductively coupled plasma mass spectrometry: enzyme-assisted water-phase microwave digestion.
We report an analytical methodology for the quantification of common arsenic species in rice and rice cereal using capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICPMS). An enzyme (i.e., α-amylase)-assisted water-phase microwave extraction procedure was used to extract four common arsenic species, including dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenite [As(III)], and arsenate [As(V)] from the rice matrices. The addition of the enzyme α-amylase during the extraction process was necessary to reduce the sample viscosity, which subsequently increased the injection volume and enhanced the signal response. o-Arsanilic acid (o-ASA) was added to the sample solution as a mobility marker and internal standard. The obtained repeatability [i.e., relative standard deviation (RSD %)] of the four arsenic analytes of interest was less than 1.23% for elution time and 2.91% for peak area. The detection limits were determined to be 0.15-0.27 ng g(-1). Rice standard reference materials SRM 1568b and CRM 7503-a were used to validate this method. The quantitative concentrations of each organic arsenic and summed inorganic arsenic were found within 5% difference of the certified values of the two reference materials.
Arkansas Regional Laboratory, Office of Regulatory Affairs, United States Food and Drug Administration (FDA), 3900 NCTR Road, Jefferson, Arkansas 72079, United States.
Haiou
H
Qu
Arkansas Regional Laboratory, Office of Regulatory Affairs, United States Food and Drug Administration (FDA), 3900 NCTR Road, Jefferson, Arkansas 72079, United States.
Thilak K
TK
Mudalige
Arkansas Regional Laboratory, Office of Regulatory Affairs, United States Food and Drug Administration (FDA), 3900 NCTR Road, Jefferson, Arkansas 72079, United States.
Sean W
SW
Linder
D001151:Arsenic / Q000737:chemistry* / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D008872:Microwaves; D012275:Oryza / Q000737:chemistry*; D000516:alpha-Amylases / Q000737:chemistry
D000516:alpha-Amylases; D001151:Arsenic
arsenic speciation; capillary electrophoresis; enzyme-assisted microwave digestion; inductively coupled plasma mass spectrometry; rice