Comparison of Simultaneous Quantitative Analysis of Methylmercury and Inorganic Mercury in Cord Blood Using LC-ICP-MS and LC-CVAFS: The Pilot Study of the Japan Environment and Children’s Study
Miyuki Iwai-Shimada,
Yayoi Kobayashi,
Tomohiko Isobe,
Shoji F. Nakayama,
Makiko Sekiyama,
Yu Taniguchi,
Shin Yamazaki,
Takehiro Michikawa,
Masako Oda,
Hiroshi Mitsubuchi,
Masafumi Sanefuji,
Shouichi Ohga,
Nathan Mise,
Akihiko Ikegami,
Reiko Suga,
Masayuki Shimono
Affiliations
Miyuki Iwai-Shimada
Japan Environment and Children’s Study Programme Office, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
Yayoi Kobayashi
Japan Environment and Children’s Study Programme Office, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
Tomohiko Isobe
Japan Environment and Children’s Study Programme Office, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
Shoji F. Nakayama
Japan Environment and Children’s Study Programme Office, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
Makiko Sekiyama
Japan Environment and Children’s Study Programme Office, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
Yu Taniguchi
Japan Environment and Children’s Study Programme Office, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
Shin Yamazaki
Japan Environment and Children’s Study Programme Office, National Institute for Environmental Studies, Tsukuba 305-8506, Japan
Takehiro Michikawa
Department of Environmental and Occupational Health, School of Medicine, Toho University, Tokyo 143-8540, Japan
Masako Oda
The Southern Kyusyu and Okinawa Regional Centre, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
Hiroshi Mitsubuchi
Department of Neonatology, Kumamoto University Hospital, Kumamoto 860-8556, Japan
Masafumi Sanefuji
Research Center for Environment and Developmental Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
Shouichi Ohga
Research Center for Environment and Developmental Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
Nathan Mise
Department of Environmental and Preventive Medicine, Jichi Medical University, Tochigi 329-0498, Japan
Akihiko Ikegami
Department of Environmental and Preventive Medicine, Jichi Medical University, Tochigi 329-0498, Japan
Reiko Suga
Regional Center for Japan Environment and Children’s Study, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
Masayuki Shimono
Regional Center for Japan Environment and Children’s Study, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan
Prenatal exposure to methylmercury (MeHg) affects child development after birth. However, many epidemiological studies have evaluated total mercury levels without analyzing speciation. Biomonitoring of MeHg and inorganic mercury (IHg) is essential to reveal each exposure level. In this study, we compared a high-throughput analysis for mercury speciation in blood using liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS) and liquid chromatography-cold vapor atomic fluorescence spectrometry (LC-CVAFS). The validated LC-ICP-MS method was applied to 101 maternal blood and 366 cord blood samples in the pilot study of the Japan Environment and Children’s Study (JECS). The accuracy of the LC-CVAFS method ranged 90–115% determined by reference material analysis. To evaluate the reliability of 366 cord blood samples, fifty cord blood samples were randomly selected and analyzed using LC-CVAFS. The median (5th–95th percentile) concentrations of MeHg and IHg were 5.4 (1.9–15) and 0.33 (0.12–0.86) ng/mL, respectively, in maternal blood, and 6.3 (2.5–15) and 0.21 (0.08–0.49) ng/mL, respectively, in cord blood. Inter-laboratory comparison showed a relatively good agreement between LC-ICP-MS and LC-CVAFS. The median cord blood:maternal blood ratios of MeHg and IHg were 1.3 and 0.5, respectively. By analyzing speciation, we could focus on the health effects of each chemical form.
