Kumkrong Paramee, Thiensong Benjaporn, Le Phuong Mai, McRae Garnet, Windust Anthony, Deawtong Suladda, Meija Juris, Maxwell Paulette, Yang Lu, Mester Zoltán
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.
Thailand Institute of Scientific and Technological Research, 35 Mu 3 Tambon Khlong Ha, Amphoe Khlong Luang, Pathum Thani, 12120, Thailand.
Anal Chim Acta. 2016 Nov 2;943:41-49. doi: 10.1016/j.aca.2016.09.031. Epub 2016 Oct 1.
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 a C-enriched AsBet spike (NRC CRM CBET-1) and an enriched spike of MeHg (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 quantitative H-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 for 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 as 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. 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.
开发了基于物种特异性同位素稀释的方法，通过液相色谱-串联质谱法（LC-MS/MS）和固相微萃取气相色谱-电感耦合等离子体质谱法（SPME GC-ICPMS）准确测定虾和乌贼组织中的砷甜菜碱（AsBet）和甲基汞（MeHg），并实现国际单位制（SI）可溯源。分别使用富含碳的AsBet内标物（NRC CRM CBET-1）和富含甲基汞的内标物（NRC CRM EMMS-1）对AsBet和MeHg进行定量，其中通过使用天然丰度的AsBet和MeHg一级标准品进行反向同位素稀释来测定内标物中分析物的质量分数。使用NIST SRM 350b苯甲酸作为一级校准物，通过定量氢核磁共振（H-NMR）对这些一级标准品的纯度进行表征，确保最终测量结果可溯源至SI。通过分析几种生物标准物质（DORM-4、TORT-3、DOLT-5、BCR-627和BCR-463）验证了所采用的同位素稀释液相色谱-串联质谱法（ID LC-MS/MS）和同位素稀释固相微萃取气相色谱-电感耦合等离子体质谱法（ID SPME GC-ICPMS），结果令人满意。所开发的方法应用于泰国科学技术研究所（TISTR）和加拿大国家研究委员会（NRC）联合生产的两种新的有证标准物质（PRON-1虾和SQID-1乌贼）中AsBet和MeHg的测定。分别在NRC和TISTR使用标准加入校准和外标法通过液相色谱-电感耦合等离子体质谱法（LC-ICPMS）对AsBet进行额外测量，新的标准物质PRON-1和SQID-1中AsBet以As计的认定值分别为1.206±0.058和13.96±0.54 mg/kg（扩展不确定度，k = 2）。仅基于同位素稀释固相微萃取气相色谱-电感耦合等离子体质谱法（ID SPME GC-ICPMS）的结果，SQID-1中MeHg以Hg计的参考值为0.324±0.028 mg/kg（扩展不确定度，k = 2），而PRON-1中MeHg含量<0.015 mg/kg。结果发现，AsBet分别占虾和乌贼中总砷的69.7%和99.0%，而MeHg占乌贼中总汞的94.5%。
