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A rapid urine creatinine assay by capillary zone electrophoresis
Author(s) -
Gatti Rosalba,
Lazzarotto Valentina,
De Palo Carlo Benedetto,
Cappellin Enrico,
Spinella Paolo,
De Palo Elio Franco
Publication year - 1999
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/(sici)1522-2683(19991001)20:14<2917::aid-elps2917>3.0.co;2-w
Subject(s) - capillary electrophoresis , chromatography , urine , chemistry , electrophoresis , biochemistry
Using capillary zone electrophoresis, the urine creatinine (uCr) assay was validated in extemporaneous diluted urine, both in healthy subjects and athletes, with the uCr concentration as a reference value to compare excretion rates of other metabolites in the same samples. The electrokinetic sample injection was carried out at 10 kV per 10 s; UV absorbance detection was at 254 nm. Using standard samples, the creatinine migration mean time in 100 mmol/L acetate buffer, pH 4.4, was 3.3 ± 0.2 min; the repeatability for absolute migration mean time was 0.6% and peak height repeatability was 2.9%. The correlation coefficient of the standard curve was r = 0.999 and the detection limit was 23.1 μmol/L. Intra‐ and interassay coefficients of variation (CV) were 3.0 and 3.6%, respectively; recovery was 99 ± 3% and linearity was r = 0.98. Normal urine samples were diluted 1:80 in run buffer. The present CE urine creatinine assay showed a good correlation with HPLC and with Jaffé methods ( r = 0.98 and r = 0.97, respectively; p < 0.0001). The uCr in the morning urine samples of 34 healthy males (M), 38 healthy females (F), and 83 male athletes (A) was 10.4 ± 6.1 mmol/L, 10.8 ± 8.1 mmol/L and 13.2 ± 6.5 mmol/L, respectively. The uCr difference ( p < 0.02) between M and A and a correlation ( p < 0.05) with age in A were observed.