Huijgen H J, van Ingen H E, Kok W T, Sanders G T
Department of Clinical Chemistry, Academic Medical Centre, Amsterdam, The Netherlands.
Clin Biochem. 1996 Jun;29(3):261-6. doi: 10.1016/0009-9120(96)84729-b.
Validation and comparison of a magnesium ion-selective electrode (ISE) with a cation-exchange resin technique, followed by determination of all magnesium fractions in serum of healthy volunteers and continuous ambulatory peritoneal dialysis (CAPD) patients.
The analytical aspect has been studied by measuring the influence of complexing agents on the fraction ionized magnesium (friMg2+). A theoretical approximation of friMg2+, based on mass equilibria and complexation constants, was calculated and compared with the measurements.
ISE measurements showed good agreement with theory. Reference values of the ionized, protein-bound, and complexed magnesium fractions were (mean +/- SD) 0.65 +/- 0.04, 0.27 +/- 0.04, and 0.08 +/- 0.03, respectively. Fractions obtained in the CAPD group were 0.62 +/- 0.04, 0.22 +/- 0.05, and 0.16 +/- 0.05, respectively, and differed significantly from the values of the reference population.
All known serum magnesium parameters can be established by a combination of ultrafiltration, atomic absorption spectrometry, and ISE measurements. Unknown complexing compounds most probably account for the increased fraction of complexed magnesium in the serum of CAPD patients.
用阳离子交换树脂技术对镁离子选择性电极（ISE）进行验证和比较，随后测定健康志愿者和持续性非卧床腹膜透析（CAPD）患者血清中所有镁组分。
通过测量络合剂对离子化镁分数（friMg2+）的影响来研究分析方面的问题。基于质量平衡和络合常数计算了friMg2+的理论近似值，并与测量值进行比较。
ISE测量结果与理论结果吻合良好。离子化、蛋白结合和络合镁组分的参考值分别为（均值±标准差）0.65±0.04、0.27±0.04和0.08±0.03。CAPD组获得的组分分别为0.62±0.04、0.22±0.05和0.16±0.05，与参考人群的值有显著差异。
所有已知的血清镁参数都可以通过超滤、原子吸收光谱法和ISE测量相结合来确定。未知的络合化合物很可能是CAPD患者血清中络合镁分数增加的原因。
