Determination of Free Calcium and Calcium-Containing Species in Human Plasma by Capillary Electrophoresis-Inductively Coupled Plasma Optical Emission Spectrometry

Abstract

A new method for the determination of free calcium concentration in human plasma was developed by online coupling capillary electrophoresis (CE) with inductively coupled plasma optical emission spectrometry (ICP-OES). Baseline separation of calcium-containing species was achieved by CE-ICP-OES in a 120-cm-long capillary with 100-microm internal diameter, at 20 kV applied voltage, with a 30 mmol/L Tris-HCl buffer at pH 7.4. A total of eight calcium-containing species were found in human plasma; the concentration of free calcium ion was found to be 41.9 mg/L. The concentrations of calcium for other seven calcium species, estimated from the calibration against Ca(2+) standard, were 3.14-15.6 mg/L. The precision (RSD, n = 10) ranged from 1.2 to 2.7% for the migration time and 2.8 to 3.9% for the peak area. The developed method was also applied to analyze plasma samples with recovery ranged from 94.5 to 102% for samples spiked with 40 mg/L free Ca(2+) ion.

Separation of metalloproteins using a novel metal ion contaminant sweeping technique and detection of protein-bound copper by a metal ion probe in polyacrylamide gel electrophoresis: distribution of copper in human serum

“…Several research groups have developed PAGE-based techniques combined with laser-ablation (LA)-ICP-MS. [29][30][31][32] Reasonable separation efficiencies have been obtained using these methods (with the typical number of theoretical plates for albumin in SEC, ion-exchange LC, CE and PAGE being 200, 33 300, 25 2700 (ref. 13) and 1200 (in this study)), with some suppression of the dissociation of metal ions from metalloproteins having been reported using the blue native (BN)-PAGE technique. 30,31 However, it has been pointed out that LA-ICP-MS has poor sensitivity and irreproducibility due to the gel drying procedure and the heterogeneous surface of the gel.…”

“…The identication and detection of metalloproteins has recently attracted a lot of interest, since knowing which proteins bind to which metal ions in biological samples is key to understanding many biological processes involving metal ions. [1][2][3][4][5][6] Various methods that enable the detection of metalloproteins have been proposed: [7][8][9][10] high-performance liquid chromatography (HPLC), 11,12 capillary electrophoresis (CE) [13][14][15][16] and polyacrylamide gel electrophoresis (PAGE)-based techniques [17][18][19][20][21][22][23] combined with instrumental elemental analysis methods, such as inductively coupled plasma atomic emission spectroscopy (ICP-AES), ICPmass spectroscopy (MS), and radioautography. While these methods are very useful for investigating the distribution of metal ions in various biological samples, they do present some difficulties.…”

Rapid and Precise Coulometric Determination of Calcium Based on Electrolysis for Ion Transfer at the Aqueous|Organic Solution Interface

“…The standard deviation (n ¼ 5) attained by FECRIT was better than 1% even when c Ca2þ was low as 10 À4 M level, and was much better than those observed for c Ca2þ of 10 À4 M level by ion selective electrode (not better than 2%) [25], ion chromatography (about 3%) [26], inductively coupled plasma emission spectroscopy (about 3%) [27], and flame atomic absorption spectrometry (about 2%) [28]. The TODGA added in DCE was found to facilitate the transfer of Ca 2þ from W to DCE selectively, and the coexistence of Mg 2þ , Na þ , K þ , or H þ did not give any effect as far as the concentrations were identical with that of Ca 2þ .…”

Design and Applications of Small Molecular Probes for Calcium Detection

“…An umber of techniques have been employed to detect calcium ions such as atomic absorption spectrometry, [8] inductive-ly coupled plasma mass spectrometry [9] and ion-selective electrodes. [10] However,t hese methods exhibit lack of selectivity as well as requireh igh cost instrumentation and extensive sample preparation.A lternatively, am ethod based on fluorescence detection is preferred due to its simplicity,h igh sensitivity and non-destructive nature.…”

“…A number of techniques have been employed to detect calcium ions such as atomic absorption spectrometry, inductively coupled plasma mass spectrometry and ion‐selective electrodes . However, these methods exhibit lack of selectivity as well as require high cost instrumentation and extensive sample preparation.…”