title: Species specific isotope dilution for the accurate and SI traceable determination of arsenobetaine and methylmercury in cuttlefish and prawn.
abstract: Methods based on species specific isotope dilution were developed for the accurate and SI traceable determination of arsenobetaine (AsBet) and methylmercury (MeHg) in prawn and cuttlefish tissues by LC-MS/MS and SPME GC-ICPMS. Quantitation of AsBet and MeHg were achieved by using a13C-enriched AsBet spike (NRC CRM CBET-1) and an enriched spike of Me198Hg (NRC CRM EMMS-1), respectively, wherein analyte mass fractions in enriched spikes were determined by reverse isotope dilution using natural abundance AsBet and MeHg primary standards. Purity of these primary standards were characterized by quantitative1H-NMR with the use of NIST SRM 350b benzoic acid as a primary calibrator, ensuring the final measurement results traceable to SI. Validation of employed methods of ID LC-MS/MS and ID SPME GC-ICPMS was demonstrated by analysis of several biological CRMs (DORM-4, TORT-3, DOLT-5, BCR-627 and BCR-463) with satisfying results. The developed methods were applied for the determination of AsBet and MeHg in two new certified reference materials (CRMs) prawn (PRON-1) and cuttlefish (SQID-1) produced jointly by Thailand Institute of Scientific and Technological Research (TISTR) and National Research Council Canada (NRC). With additional measurements of AsBet using LC-ICPMS with standard additions calibration and external calibration at NRC and TISTR, respectively, certified values of 1.206 ± 0.058 and 13.96 ± 0.54 mg kg-1for AsBet as As (expanded uncertainty, k = 2) were obtained for the new CRMs PRON-1 and SQID-1, respectively. The reference value of 0.324 ± 0.028 mg kg-1as Hg (expanded uncertainty, k = 2) for MeHg was obtained for the SQID-1 based on the results obtained by ID SPME GC-ICPMS method only, whereas MeHg in PRON-1 was found to be < 0.015 mg kg-1. It was found that AsBet comprised 69.7% and 99.0% of total As in the prawn and cuttlefish, respectively, whereas MeHg comprised 94.5% of total Hg in cuttlefish.
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada; Thailand Institute of Scientific and Technological Research, 35 Mu 3 Tambon Khlong Ha, Amphoe Khlong Luang, Pathum Thani, 12120, Thailand.
authors: Paramee
authors: P
authors: Kumkrong
authors: Thailand Institute of Scientific and Technological Research, 35 Mu 3 Tambon Khlong Ha, Amphoe Khlong Luang, Pathum Thani, 12120, Thailand.
authors: Benjaporn
authors: B
authors: Thiensong
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada.
authors: Phuong Mai
authors: PM
authors: Le
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada.
authors: Garnet
authors: G
authors: McRae
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada.
authors: Anthony
authors: A
authors: Windust
authors: Thailand Institute of Scientific and Technological Research, 35 Mu 3 Tambon Khlong Ha, Amphoe Khlong Luang, Pathum Thani, 12120, Thailand.
authors: Suladda
authors: S
authors: Deawtong
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada.
authors: Juris
authors: J
authors: Meija
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada.
authors: Paulette
authors: P
authors: Maxwell
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada. Electronic address: Lu.yang@nrc-cnrc.gc.ca.
authors: Lu
authors: L
authors: Yang
authors: National Research Council Canada, 1200 Montreal Rd, Ottawa, Ontario, K1A 0R6, Canada.
authors: Zoltán
authors: Z
authors: Mester
mesh_terms: D000818:Animals; D001152:Arsenicals / Q000032:analysis*; D002853:Chromatography, Liquid; D003445:Crustacea / Q000737:chemistry*; D049832:Decapodiformes / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D008767:Methylmercury Compounds / Q000032:analysis*; D066244:Proton Magnetic Resonance Spectroscopy; D013045:Species Specificity
chemical_list: D001152:Arsenicals; D008767:Methylmercury Compounds; C038992:arsenobetaine
keywords: Arsenobetaine; Certified reference material; Isotope dilution; Methylmercury; Speciation