Drop-coating deposition Raman spectroscopy for quantitative detection of urinary creatinine: a feasibility study

Abstract

We present the results of an exploratory study carried out to evaluate the applicability of drop coating deposition Raman spectroscopy (DCDRS) for quantitative determination of creatinine present in urine. A comparison of the conventional Raman and the DCDRS spectra measured from aqueous solutions of physiological concentration of creatinine showed significantly higher intensity for DCDRS. Although as compared to surface enhanced Raman spectroscopy (SERS) this intensity was considerably lower, the reproducibility of DCDRS was found to be significantly better (⩾92%) than that of SERS (∼75%). A multivariate chemometric algorithm based on partial least square regression was developed to predict the concentrations of creatinine on the basis of the measured set of DCDRS spectra of the aqueous creatinine solutions as well as artificial urine samples and the reference (known) concentrations of creatinine used for preparing the solutions. The algorithm, applied via leave-one-spectrum-out cross-validation, could detect creatinine present in the artificial urine samples with an accuracy of over 94% in the physiological concentration range. Further, the lower limit of detection was also found to be sufficient for determining the presence of the urinary creatinine levels lower than the physiological reference range. Overall, the findings of the study demonstrate a promising potential of DCDRS for quantitative analysis of creatinine present in urine.