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Performance of ion chromatography to measure picomole amounts of magnesium in nanolitre samples
Author(s) -
Figueres Lucile,
ProtBertoye Caroline,
Morla Luciana,
Ferriere Elsa,
Griveau Camille,
Brideau Gaëlle,
Baron Stéphanie,
Houillier Pascal
Publication year - 2020
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jp280304
Subject(s) - magnesium , chemistry , chromatography , divalent , organic chemistry
Key points An UHPLC method to measure picomole amounts of magnesium has been developed. The method is sensitive, specific, accurate and reproducible. The method is suitable for quantifying magnesium transport across intact epithelia.Abstract Magnesium is involved in many biological processes. Extracellular magnesium homeostasis mainly depends on the renal handling of magnesium, the study of which requires measurement of low concentrations of magnesium in renal tubular fluid. We developed an ultra‐high‐performance liquid chromatography method to measure millimolar concentrations of magnesium in nanolitre samples. Within‐assay and between‐assay coefficients of variation were lower than 5% and 6.6%, respectively. Measurement of magnesium concentration was linear ( r 2 = 0.9998) over the range 0–4 mmol/l. Absolute bias ranged from −0.03 to 0.05 mmol/l. The lower limit of quantification was 0.2 mmol/l. Recovery was 97.5–100.3%. No significant interference with calcium, another divalent cation present in the same samples, was detected. The method was successfully applied to quantify transepithelial magnesium transport by medullary and cortical thick ascending limbs during ex vivo microperfusion experiments. In conclusion, ultra‐high‐performance liquid chromatography is suitable for measurement of picomole amounts of magnesium in renal tubular fluid. The method allows detailed studies of transepithelial magnesium transport across native epithelium.