title: Speciation analysis of arsenic in prenatal and children's dietary supplements using microwave-enhanced extraction and ion chromatography-inductively coupled plasma mass spectrometry.
abstract: A study was conducted to develop a microwave-enhanced extraction method for the determination of arsenic species in prenatal and children's dietary supplements prepared from plant materials. The method was optimized by evaluating the efficiency of various solutions previously used to extract arsenic from the types of plant materials used in the dietary supplement formulations. A multivitamin standard reference material (NIST SRM 3280) and a prenatal supplement sample were analyzed in the method optimization. The identified optimum conditions were 0.25 g of sample, 5 mL of 0.3 mol L(-1) orthophosphoric acid (H3PO4) and microwave heating at 90 °C for 30 min. The extracted arsenic was speciated by cation exchange ion chromatography-inductively coupled plasma mass spectrometry (IC-ICP-MS). The method detection limit (MDL) for the arsenic species was in the range 2-8 ng g(-1). Ten widely consumed prenatal and children's dietary supplements were analyzed using the optimized protocol. The supplements were found to have total arsenic in the concentration range 59-531 ng g(-1). The extraction procedure recovered 61-92% of the arsenic from the supplements. All the supplementary products were found to contain arsenite (As(3+)) and dimethylarsinic acid (DMA). Arsenate (As(5+)) was found in two of the supplements, and an unknown specie of arsenic was detected in one product. The results of the analysis were validated using mass balance by comparing the sum of the extracted and non-extracted arsenic with the total concentration of the element in the corresponding samples.
authors.affiliation: Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States. Electronic address: wollem@duq.edu.
authors.forename: Mesay M
authors.initials: MM
authors.lastname: Wolle
authors.affiliation: Applied Isotope Technologies, 2403 Sidney Street, Suite 280, Pittsburgh, PA 15203, United States.
authors.forename: G M Mizanur
authors.initials: GM
authors.lastname: Rahman
authors.affiliation: Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, United States.
authors.forename: H M Skip
authors.initials: HM
authors.lastname: Kingston
authors.affiliation: Applied Isotope Technologies, 2403 Sidney Street, Suite 280, Pittsburgh, PA 15203, United States.
authors.forename: Matt
authors.initials: M
authors.lastname: Pamuku
mesh_terms: D001149:Arsenates / Q000032:analysis; D001152:Arsenicals / Q000032:analysis* / Q000302:isolation & purification / Q000592:standards; D018053:Arsenites / Q000032:analysis; D002101:Cacodylic Acid / Q000032:analysis; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002648:Child; D002852:Chromatography, Ion Exchange / Q000592:standards; D019587:Dietary Supplements / Q000032:analysis*; D005260:Female; D006801:Humans; D013058:Mass Spectrometry / Q000592:standards; D008872:Microwaves; D010756:Phosphoric Acids / Q000737:chemistry; D010944:Plants / Q000737:chemistry / Q000378:metabolism; D011247:Pregnancy; D012015:Reference Standards; D013607:Tablets / Q000737:chemistry; D013696:Temperature
chemical_list: D001149:Arsenates; D001152:Arsenicals; D018053:Arsenites; D010756:Phosphoric Acids; D013607:Tablets; D002101:Cacodylic Acid; C030242:phosphoric acid; C015001:arsenite; C025657:arsenic acid
keywords: Arsenic; Dietary supplement; Inductively coupled plasma mass spectrometry; Ion chromatography; Microwave-enhanced extraction; Speciation analysis