Analytical isotachophoresis: A rapid and sensitive method for determination of urinary oxalate

Schmidt, Karl‐Heinz; Hagmaier, V.; Bruchelt, Gernot; Rutishauser, G

doi:10.1007/bf00256414

Cited by 20 publications

(8 citation statements)

References 9 publications

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“…Hatch et al [21] reported an unexpected urinary oxa late peak 7 days after stopping high-dose vita min C supplementation and explained this as a late effect of decreased renal clearance fol lowed by flushing out of retained oxalate. Conversely, Schmidt et al [22], who had de veloped an isotachophoretic method [23], could not confirm these findings and noted instead that after cessation of high-dose vita min C intakes oxalate excretion returned to baseline values within 1 day.…”

Section: The Origin Of Urinary Oxalatementioning

confidence: 78%

No Contribution of Ascorbic Acid to Renal Calcium Oxalate Stones

Gerster¹

1997

Ann Nutr Metab

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Even though a certain part of oxalate in the urine derives from metabolized ascorbic acid (AA), the intake of high doses of vitamin C does not increase the risk of calcium oxalate kidney stones due to physiological regulatory factor: gastrointestinal absorption as well as renal tubular reabsorption of AA are saturable processes, and the metabolic transformation of AA to oxalate is limited as well. Older assays for urinary oxalate favored in vitro conversion of AA to oxalate during storage and processing of the samples. Recurrent stone formers and patients with renal failure who have a defect in AA or oxalate metabolism should restrict daily vitamin C intakes to -100 mg. But in the large-scale Harvard Prospective Health Professional Follow-Up Study, those groups in the highest quintile of vitamin C intake (> 1,500 mg/day) had a lower risk of kidney stones than the groups in the lowest quintiles.

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Section: The Origin Of Urinary Oxalatementioning

confidence: 78%

No Contribution of Ascorbic Acid to Renal Calcium Oxalate Stones

Gerster¹

1997

Ann Nutr Metab

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“…13 ITP has earlier been applied to urine samples, primarily for measurement of small molecules. 14–21 The latter studies have been typically performed on long separation capillaries using electrochemical detection, electric potentials of 10 kV or higher, and separation times on the order of tens of minutes to hours. More recently, on-chip ITP has been applied to extraction and purification of biological samples: Schoch et al 22 demonstrated the use of ITP for extraction of short RNA from bacterial lysate using a sieving matrix, Persat et al performed extraction of DNA from whole blood using ITP, 23 and Matsumura et al used ITP for extraction of DNA from cultured bacteria lysate.…”

Section: Introductionmentioning

confidence: 99%

Rapid Detection of Urinary Tract Infections Using Isotachophoresis and Molecular Beacons

et al. 2011

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We present a novel assay for rapid detection and identification of bacterial urinary tract infections using isotachophoresis (ITP) and molecular beacons. We applied on-chip ITP to extract and focus 16S rRNA directly from bacterial lysate, and used molecular beacons to achieve detection of bacteria specific sequences. We demonstrated detection of E. coli in bacteria cultures as well as in patient urine samples in the clinically relevant range 1E6-1E8 cfu/mL. For bacterial cultures we further demonstrate quantification in this range. The assay requires minimal sample preparation (a single centrifugation and dilution), and can be completed, from beginning of lysing to detection, in under 15 min. We believe that the principles presented here can be used for design other rapid diagnostics or detection methods for pathogenic diseases.

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“…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.…”

Section: Working Conditions In the Separations On The Chipmentioning

confidence: 99%

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

et al. 2002

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The use of a poly(methylmethacrylate) capillary electrophoresis chip, provided with a high sample load capacity separation system (a 8500 nL separation channel coupled to a 500 nL sample injection channel) and a pair of on-chip conductivity detectors, for zone electrophoresis (ZE) determination of oxalate in urine was studied. Hydrodynamic and electroosmotic flows of the solution in the separation compartment of the chip were suppressed and electrophoresis was a dominant transport process in the separations performed on the chip. A low pH of the carrier electrolyte (4.0) provided an adequate selectivity in the separation of oxalate from anionic urine constituents and, at the same time, also a sufficient sensitivity in its conductivity detection. Under our working conditions, this anion could be detected at a 8 x 10(-8) mol/L concentration also in samples containing chloride (a major anionic constituent of urine) at 3.5 x 10(-3) mol/L concentrations. Such a favorable analyte/matrix concentration ratio (in part, attributable to a transient isotachophoresis stacking in the initial phase of the separation) made possible accurate and reproducible (typically, 2-5% relative standard deviation (RSD) values of the peak areas of the analyte in dependence on its concentration in the sample) determination of oxalate in 500 nL volumes of 20-100-fold diluted urine samples. Short analysis times (about 280 s), no sample pretreatment (not considering urine dilution) and reproducible migration times of this analyte (0.5-1.0% RSD values) were characteristic for ZE on the chip. This work indicates general potentialities of the present chip design in rapid ZE analysis of samples containing the analyte(s) at high ionic matrix/analyte concentration ratios.

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Analytical isotachophoresis: A rapid and sensitive method for determination of urinary oxalate

Cited by 20 publications

References 9 publications

No Contribution of Ascorbic Acid to Renal Calcium Oxalate Stones

No Contribution of Ascorbic Acid to Renal Calcium Oxalate Stones

Rapid Detection of Urinary Tract Infections Using Isotachophoresis and Molecular Beacons

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

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