Institute of Chemistry, Analytical Chemistry for the Health and Environment, University of Graz, Universitaetsplatz 1, 8010 Graz, Austria.
Institute of Chemistry, TESLA (Trace Element Speciation Laboratory), University of Graz, Universitaetsplatz 1, 8010 Graz, Austria.
Anal Chem. 2022 Jun 21;94(24):8802-8810. doi: 10.1021/acs.analchem.2c01769. Epub 2022 Jun 6.
The inductively coupled plasma mass spectrometry (ICPMS) has been attracting increasing attention for many applications as an element-selective chromatographic detector. A major and fundamental limitation in coupling ICPMS with liquid chromatography is the limited compatibility with organic solvents, which has so far been addressed via a tedious approach, collectively referred to as the "organic ICPMS mode", that can decrease detection sensitivity by up to 100-fold. Herein, we report 1,2-hexanediol as a new eluent in high-performance liquid chromatography-ICPMS which enables avoiding the current limitations. Unlike commonly used eluents, 1,2-hexanediol was remarkably compatible with ICPMS detection at high flow rates of 1.5 mL min and concentrations of at least 30% v/v, respectively, under the standard conditions and instrumental setup normally used with 100% aqueous media. Sensitivity for all tested elements (P, S, Cl, Br, Se, and As) was enhanced with 10% v/v 1,2-hexanediol relative to that of 100% aqueous media by 1.5-7-fold depending on the element. Concentrations of 1,2-hexanediol at ≤30% v/v were superior in elution strength to concentrations at >90% v/v of the common organic phases, which greatly decreases the amount of carbon required to elute highly hydrophobic compounds such as lipids and steroids, enabling detection at ultra-trace levels. The proposed approach was applied to detect arsenic-containing fatty acids in spiked human urine, and detection limits of <0.01 μg As L were achieved, which is >100-fold lower than those previously reported using the organic ICPMS mode. Nontargeted speciation analysis in revealed the presence of a large number of hydrophobic sulfur-containing metabolomic features at trace levels.
电感耦合等离子体质谱 (ICPMS) 作为一种元素选择性色谱检测器，因其许多应用而受到越来越多的关注。将 ICPMS 与液相色谱法耦合的一个主要和根本限制是与有机溶剂的兼容性有限，迄今为止，这一问题一直通过一种繁琐的方法来解决，统称为“有机 ICPMS 模式”，该方法可使检测灵敏度降低多达 100 倍。在此，我们报告了 1,2-己二醇作为高效液相色谱-ICPMS 中的一种新洗脱剂，可避免当前的限制。与常用的洗脱剂不同，1,2-己二醇在标准条件下，分别在高达 1.5 mL min 的高流速和至少 30% v/v 的浓度下与 ICPMS 检测具有出色的兼容性，且所用的仪器设置与 100%水介质通常相同。与 100%水介质相比，所有测试元素（P、S、Cl、Br、Se 和 As）的灵敏度在 10% v/v 1,2-己二醇下提高了 1.5-7 倍，具体取决于元素。在 1,2-己二醇浓度≤30% v/v 时，洗脱强度优于常用有机相浓度>90% v/v，这大大减少了洗脱高度疏水性化合物（如脂质和类固醇）所需的碳量，可实现超痕量检测。所提出的方法应用于检测加标人尿中含砷脂肪酸，检测限<0.01 μg As L，比以前使用有机 ICPMS 模式报道的检测限低 100 倍以上。非靶向代谢组学分析表明，痕量水平存在大量疏水性含硫代谢组学特征。
