Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometric Determination of Creatinine in Human Urine

The ability to measure creatinine with good accuracy is essential as its urinary concentration is used to quantify other analytes in urinalysis. In this study, an assay for the determination of creatinine in human urine by hydrophilic interaction liquid chromatography and electrospray ionization tandem mass spectrometry was developed and validated. Hydrophilic interaction chromatography provided retention of creatinine well away from the early eluting impurities that can reduce sensitivity by suppression of the mass spectrometry signal. Ion suppression effects were further eliminated by using a co-eluting, stable-isotope labeled creatinine as the internal standard. The resultant limit of detection was 1.5 picomoles, requiring a sample size of less than 10 µL of urine. The use of tandem mass spectrometry with a stable isotope labeled internal standard provided high specificity, accuracy, and precision for this assay resulting a recovery of 93.9% and a repeatability standard deviation of 3.78%.