Inorganic Chemical Metrology Group, Analytical Chemistry Division, National Institute of Standards and Technology, 100 Bureau Drive, MS8391, Gaithersburg, MD 20899, USA.
Rapid Commun Mass Spectrom. 2010 Sep 15;24(17):2673-9. doi: 10.1002/rcm.4686.
Methionine is an essential amino acid and is the primary source of sulfur for humans. Using the double spike ((33)S-(36)S) multi-collector thermal ionization mass spectrometry (MC-TIMS) technique, three sample bottles of a methionine material obtained from the Institute for Reference Materials and Measurements have been measured for delta(34)S and sulfur concentration. The mean delta(34)S value, relative to Vienna Canyon Diablo Troilite (VCDT), determined was 10.34 +/- 0.11 per thousand (n = 9) with the uncertainty reported as expanded uncertainties (U). These delta(34)S measurements include a correction for blank which has been previously ignored in studies of sulfur isotopic composition. The sulfur concentrations for the three bottles range from 56 to 88 microg/g. The isotope composition and concentration results demonstrate the high accuracy and precision of the DS-MC-TIMS technique for measuring sulfur in methionine.
甲硫氨酸是一种必需氨基酸，也是人体硫的主要来源。使用双标记（33S-36S）多接收热电离质谱（MC-TIMS）技术，对来自参考物质和测量研究所的甲硫氨酸材料的三个样品瓶进行了δ34S 和硫浓度的测量。相对于维也纳峡谷迪比罗特里尔（VCDT），测定的平均δ34S 值为 10.34±0.11‰（n=9），报告的不确定度为扩展不确定度（U）。这些δ34S 测量值包括对空白的修正，这在以前的硫同位素组成研究中被忽略了。三个瓶子的硫浓度范围为 56 至 88 微克/克。同位素组成和浓度结果表明，DS-MC-TIMS 技术在测量甲硫氨酸中的硫具有很高的准确性和精度。
