LC-MS-MS Measurements of Urinary Creatinine and the Application of Creatinine Normalization Technique on Cotinine in Smokers’ 24 Hour Urine

Figure 4

Comparison of human urine creatinine measured by LC-MS-MS and enzymatic colorimetric methods (𝑛=28). Solid line show linear fit lines:  =1.058𝑥−141.486, 𝑅²=0.966, 𝑃<0.0001.