Multicollector inductively coupled plasma–mass spectrometry with 1013 Ω Faraday cup amplifiers for ultrasensitive Mg isotopic analysis of cerebrospinal fluid microsamples

Ondertitel:Multicollector inductively coupled plasma–mass spectrometry with 10(13) Omega Faraday cup amplifiers for ultrasensitive Mg isotopic analysis of cerebrospinal fluid microsamples

Magnesium isotopic analysis of cerebrospinal fluid (CSF) is a potentially interesting approach for studies on neurodegeneration. However, this type of analysis is challenging because of the invasiveness of the sampling and small sample volume. In this work, a novel analytical method was developed for ultrasensitive Mg isotopic analysis of CSF microsamples via multicollector inductively coupled plasma-mass spectrometry (MC-ICP-MS) using high-gain 10(13) Omega Faraday cup amplifiers. The intermediate and internal errors on the delta Mg-26 value were improved up to fourfold using 10(13) Omega resistors for the monitoring of both the Mg-24 and Mg-26 isotopes and up to twofold using a 10(11) Omega resistor for the most abundant Mg-24 isotope and a 10(13) Omega resistor for the Mg-26 isotope. Magnesium isotope ratios measured at a concentration level of 7-10 mu g L-1 were in good agreement with those obtained using the conventional method at a concentration level of 150 mu g L-1. The expanded uncertainty for the quality control CSF material obtained at the ultratrace level was +/- 0.16 parts per thousand. Ultrasensitive Mg isotopic analysis was carried out for CSF from hydrocephalus patients using only 5 mu L of sample. delta Mg values thus obtained were not significantly different from those obtained using the conventional method using a sample volume of 400 mu L instead (p <= 0.05). The Mg isotopic composition of the CSF from hydrocephalus patients ranged between -0.65 and 0.30 parts per thousand, with a mean delta Mg-26 value of -0.14 +/- 0.27 parts per thousand.

Jaar van publicatie:2020

Toegankelijkheid:Closed