Determination of creatinine, creatine, and GAA
A rapid and direct method for simultaneous determination of creatinine, creatine, and guanidinoacetic acid in biological samples has been developed by using column liquid chromatography-mass spectrometry (LC/APCI-MS). The determinations of creatinine, creatine, and guanidinoacetic acid in the samples of human urine and serum were carried out by scanning the [M + H]+ ions of each compound. The recoveries of authentic compounds were 93.87 +/- 6.00% (n = 5) for creatinine, 94.80 +/- 8.93% (n = 5) for creatine, and 90. 92 +/- 7.96% (n = 5) for guanidinoacetic acid after ion-exchange resin treatment. The content of creatinine in human urine and serum was also measured by the Jaffé method, a common method of determination of creatinine currently used in hospitals. The contents of creatinine, creatine, and guanidinoacetic acid obtained using LC/APCI-MS coincided well with those reported in previous papers.
Yasuda M, Sugahara K, Zhang J, Ageta T, Nakayama K, Shuin T, Kodama H. Simultaneous determination of creatinine, creatine, and guanidinoacetic acid in human serum and urine using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. Anal Biochem. 1997 Nov 15;253(2):231-5.