Development of DRC-ICP-MS methodology for the rapid determination of ⁵⁸Fe erythrocyte incorporation in human iron absorption studies

Iron deficiency is the only major nutritional deficiency that still exists in the developed world and iron deficiency anaemia affects nearly one billion people worldwide (Benoist et al., Worldwide prevalence on anaemia 1993-2005, WHO, 2008). However, iron supplements are still not optimally formulated so cheap, side effect-free and well absorbed iron supplements are sought. The development of these requires the determination of iron absorption in animals, volunteers or patients, typically by determining iron isotopic enrichment in blood after administering isotopically labelled iron supplements. Current analytical techniques for isotope ratio work, such as thermal ionisation mass spectrometry (TIMS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), have a low throughput, due to the requirements of sample pre-treatment and, generally, are not present in clinical or nutritional laboratories. Here we describe a novel, more accessible, dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) method for the determination of ⁵⁸Fe enrichment in samples from nutritional or clinical studies. This is a high throughput method, in which the samples require no pre-treatment other than dilution, that was validated against MC-ICP-MS, and was shown to be fit-for-purpose.