Elemental analysis for the determination of micronutrient status in biological samples: Applications for pregnancy research

Abstract

Objectives: Aberrant micronutrient deficiencies are associated with arange of perinatal outcomes and concomitant with gestational disorderssuch as: gestational diabetes mellitus; preeclampsia; and an increased riskof foetal growth restriction, preterm birth and stillbirth. This project aimsto develop a comprehensive method to determine concentrations ofessential micronutrients in a single blood sample; ultimately describingthe individual’s micronutrient profile, and aiming to identify women atrisk of complications. Methods: Inductively coupled plasma mass spectrometry (ICP-MS) wasused to simultaneous measure elements in samples of serum, plasmaand whole blood. For primary methodology optimisation, cord bloodsamples (n¼9) were collected from the Gold Coast UniversityHospital, Australia. Two ICP-MS sample preparation methodologies weretrialled: dilution with (1) 2% nitric acid (HNO3), and (2) a solution ofEDTA and Ammonia. Testing involved determining dilution factors,specificity, intra-assay variation and inter-assay variation on 69 ele-ments. For secondary determination of elements associated with preg-nancy complications, cord blood samples from the Environments forHealthy Living (EFHL) cohort (n¼160) were screened with the optimisedmethod. Results: EDTA-based preparation was used due to significantly lowerintra- and inter-assay variation for sera, plasma, and whole blood samples.Furthermore, it had significantly higher specificity for the majority of el-ements, allowing for increased distinction between elemental concentra-tions (p<0.05). In the EFHL samples, 40 elements were able to be analysed,however 13 were excluded due to higher than 10% variation within trip-licates; 27 elements were determined to be highly reproducible (<10%variation) in this simultaneous analysis. Conclusion: This study is thefirst to analyse 27 elements in pregnancysamples. Hallmark elements measured include: sodium, magnesium, po-tassium, calcium, manganese, iron, zinc, selenium, molybdenum, lead andiodine. The number of quantifiable micronutrients could provide immensestatistical power for analysis of gestational disorders, providing insightinto ways to minimise disease outcomes through supplemental micro-nutrition