New reagent for colorimetric assay of calcium in serum.
We report a new single-reagent colorimetric assay for the determination of calcium in serum. The assay is based on a novel chromogenic tetracarboxylic acid chelating agent. The method has several advantages over the o-cresolphthalein complexone (CPC) method, including improved linearity, better accuracy, increased stability, and lower working pH (9.0). The calibration curve for the assay is linear up to 4 mmol/L. The results for 47 patients' samples correlated well with results obtained with an Instrumentation Laboratory atomic absorption spectrophotometer. The mean (+/- SD) calcium values for the new method were 2.27 +/- 0.06 mmol/L and 2.26 +/- 0.05 mmol/L for the comparison method. The on-system stability of the reagents is 1 week vs 8 h for the CPC method.
Miles Inc., Tarrytown, NY 10591.
E
E
Chapoteau
B P
BP
Czech
W
W
Zazulak
A
A
Kumar
D002118:Calcium / Q000097:blood*; D002614:Chelating Agents / Q000138:chemical synthesis*; D002863:Chromogenic Compounds / Q000138:chemical synthesis*; D003124:Colorimetry / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity
D002614:Chelating Agents; D002863:Chromogenic Compounds; D002118:Calcium