Simultaneous analysis of creatinine and uric acid in human urine samples using mean centering, ratio subtraction, and derivative spectrophotometric techniques as a green analytical protocol

Four rapid, accurate, and straightforward derivative spectrophotometric methods were developed to quantify a binary mixture of creatinine (CRT) and uric acid (UA) in human urine samples. The first technique was based on a zero-crossing technique for first-derivative spectrophotometry. The second technique was based on the first derivative of the ratio spectra. The third technique was based on the ratio subtraction method. The fourth technique was based on the mean centring of ratio spectra. There are no prior separation processes in these methods. The calibration graphs for the four spectrophotometric techniques are linear in the concentration ranges 1.0 – 16.0 µg/mL and 2.0 – 15.0 µg/mL for CRT and UA, respectively. CRT determines the selected wavelength 261.71 nm zero-crossing point for UA, while UA can be chosen at 234 and 282 nm zero-crossing points of CRT. The limit of detection ranged from 0.025 µg/mL to 0.330 µg/mL, and the limit of quantification was 0.076 µg/mL to 0.998 µg/mL for CRT and 0.115 µg/mL to 0.622 µg/mL and 0.176 µg/mL to 1.885 µg/mL for UA. The recoveries ranged from 97.93 – 103.07 % for CRT and 97.03 –102.11 % for UA, with relative standard deviations of <4.55 % and 2.07 % for CRT and UA, respectively. With a one-way ANOVA, the results of the suggested procedures were compared. The outcomes didn't reveal any appreciable variations among the proposed methods. The greenness of the methods compared with the literature using white analytical chemistry, analytical greenness, and green analytical procedure index, where the results indicated that the proposed methods were greener than the literature methods.