Eugster R, Rusterholz B, Schmid A, Spichiger U E, Simon W
Department of Organic Chemistry, Swiss Federal Institute of Technology (ETH), Zürich.
Clin Chem. 1993 May;39(5):855-9.
A magnesium ion-selective liquid membrane electrode based on a synthetic neutral carrier is presented. The selectivity for Mg2+ over Na+, K+, and H+ is sufficient for assays in the physiological range, but a chemometric correction of approximately 10% is still necessary for the Ca2+ interference. We optimized the membrane composition especially with respect to selectivity and accuracy by performing a new characterization procedure in which we simulated the variety of blood serum samples with 10 aqueous solutions. After a three-point calibration, these solutions were measured alternately with the middlerange calibrator for 3 min. The magnesium activity was evaluated after correcting for the calcium interference according to the Nikolsky equation. The selectivity coefficient, KpotMgCa, was itself fitted to give the minimum deviations from the assigned magnesium activities. Electrodes with an optimized membrane composition show an average deviation from theoretical activity values of about 1.6% with logKpotMgCa = -0.8.
介绍了一种基于合成中性载体的镁离子选择性液膜电极。在生理范围内，该电极对Mg2+相对于Na+、K+和H+的选择性足以用于分析，但对于Ca2+干扰仍需要约10%的化学计量校正。我们通过执行一种新的表征程序来优化膜组成，特别是在选择性和准确性方面，在该程序中我们用10种水溶液模拟了各种血清样本。经过三点校准后，这些溶液与中间范围校准液交替测量3分钟。根据尼科尔斯基方程校正钙干扰后评估镁活性。选择性系数KpotMgCa本身经过拟合，以使与指定镁活性的偏差最小。具有优化膜组成的电极显示，与理论活性值的平均偏差约为1.6%，logKpotMgCa = -0.8。
