Determination of Urinary Oxalate by Isotachophoresis Practical Improvement and Critical Evaluation

Abstract

We developed an eleetronic control unit for the determination of oxalate in urine by isotachophoresis with the LKB 2127 Tachophor. It permits a considerable reduction of the time required for analysis. Measurements were carried out in samples of untreated urine using different leading electrolytes and standardization procedures. Determination of oxalate can be thus achieved within 25 min, whereof the manpower expenditure is about 5 min. In the ränge of 1.0-0.1 mmol/1 urinary oxalate can be determined with a coefficient of Variation of 4-6%. The detection limit of the method is about 0.04 mmol/1. * Bestimmung von Urinoxalat durch Isotachophorese -Praktische Verbesserungen und kritische BewertungZusammenfassung: Es wird ein Zusatzgerät zur Isotachophorese-Apparatur LKB 2127 Tachophor beschrieben, das eine Verkürzung der Analysenzeit zur Bestimmung von Oxalat im Harn ermöglicht. Oxalatbestimmungen wurden im nichtvorbehandelten Urin mit verschiedenen Leitelektrolyten durchgeführt und unterschiedlich ausgewertet. Der Messung bei pH 2.3 (Leitelektrolyt enthält HC1 und NaCl) ist wegen der größeren Effektivität und Richtigkeit der Vorrang zu geben. Eine Bestimmung erfordert 25 min bei einem tatsächlichen Arbeitszeitaufwand von etwa 5 min. Im Bereich l ,0-0,1 mmol/1 Oxalat liegt der Variationskoeffizient zwischen 4 und 6%. Die Nachweisgrenze ist etwa 0,04 mmol/1. Introducrion

Determination of oxalate in urine by zone electrophoresis on a chip with conductivity detection

“…The cLOD value as achieved for this analyte with the aid of the conductivity detector under our separating conditions (8610 -8 mol/L for a 500 nL sample volume) is very competitive to those reported for conventional CE [27][28][29][30][31][32][33][34][35], ion chromatography [46][47][48][49] and other analytical techniques (see, e.g., [51][52][53]). The cLOD value as achieved for this analyte with the aid of the conductivity detector under our separating conditions (8610 -8 mol/L for a 500 nL sample volume) is very competitive to those reported for conventional CE [27][28][29][30][31][32][33][34][35], ion chromatography [46][47][48][49] and other analytical techniques (see, e.g., [51][52][53]).…”

“…Chloride, having an absolute ionic mobility close to that of the double charged ionic form of oxalate [40], is present in urine samples at 0.5-1.5610 -1 mol/L concentrations while the oxalate concentration in urine is approximately three orders of magnitude lower [27][28][29][30][31][32][33][34][35]. Therefore, the resolution of oxalate from chloride may be considered a critical step in the ITP and CZE determination of the former anion in urine.…”

Vegetables and Vegetable Products

“…Gas chtomatography (Charransol et al 1978;Hesse et al 1980), high-performance liquid chromatography (Libert 1981;Wilson et al 1982;Grun and Loewus 1983), and isotachophoresis (Schwendtner et al 1982) have been employed for oxalate determination, and enzyme-based methods (Knowles and Hodgkinson 1972;Beutler et al 1980;Kohlbecker and Burtz 1981) have been described. In recent years, however, several modem methods for oxalate analysis in foods, especially vegetables and other samples, have been reported.…”

HPLC Analysis of Human Urine for Oxalate Content

“…Hence gas chromatographic [8][9][10], high performance liquid chromatographic [11][12][13], ion pair chromatographic [14][15] methods have been developed for analysis of oxalate from biological fluids. The various other enzymatic [16][17][18][19][20][21], colorimetric [22,23] and Isotachophoresis [24,25] methods have been developed for analysis of oxalate from biological fluids and in the presence of oxalate concentration altering bio-molecules like ascorbic acid. Among all these methods, oxalate oxidase (OO) method was most widely used as it was developed in the form of a colorimetric kit which will give accurate, robust and uniform result when you analyze the same at any centre over the entire globe.…”