Agradecimentos: This work was supported by the Coordination of Superior Level Staff Improvement – Brasil (CAPES) – Finance Code 001; Brazillian National Council for Scientific and Technological Development (CNPQ: 424032/2018-0, 303867/2020-5, Schorlaship: 142502/2020-0); Funding Authority for Studies and Projects (FINEP) (CT-INFRA 01/2013-REF 0633/13); RQ-MG (CEX.RED- 00010–14); National Institute of Science and Technology for Bioanalytics (INCTBio) (FAPESP 2014/50867-3, CNPq 465389/2014-7, 401256/2020-0); State of Minas Gerais Research Support Foundation (FAPEMIG) (APQ-00585-21). The authors thank the team of collaborators from Lemos Laboratório de Análises Clínicas for the collection and donation of samples Ver menos

Abstract: Creatinine is a well-stablished biomarker for kidney malfunctions and for normalization parameter of urinary quantitative information. Recently, metabolic studies have been discovering other functionalities for creatinine tests in human urine and blood serum. In this work we present an enhanced capillary electrophoresis (CE) based protocol for determination of creatinine. CE is a high-throughput separation technique that have been getting attention through the last decades and might be considered to be adopted as an analytical instrumentation for clinical purposes. In the proposed method, we performed a short injection program with on-column addition of internal standard. Additionally, the method allows a simultaneous screening of non-proteinogenic amino acids that could be considered for metabolomics purposes. We design a pilot study that successfully estimated the creatinine value in 100 urine samples with (2.85 ± 1.78) mg dL-1 LOD; (8.24 ± 5.93) mg dL-1 LOQ and 82.4% accuracy. Considering that serum creatinine is also included in the clinical laboratory routines for estimated Glomerular Filtration Rate dosage, the method was complementary applied to 10 blood serum samples, which resulted in a model with (0.4 ± 0.2) mg dL-1 LOD; (2.0 ± 0.6) mg dL-1 LOQ and 83.8% of accuracy. All results were in agreement with reference values. The proposed method promotes a great analytical frequency and reproducibility with enhanced specificity compared with the ongoing protocol by Jaffe's reaction, thereby proving to be useful as an alternative for creatinine exams that might help complete a diagnosis of a series of health-related issues Ver menos