“…A high-or ultra-high-performance liquid chromatography (HPLC or UHPLC) in combination with ultraviolet (UV) or mass spectrometry (MS) has been recently used for the determination of creatinine in urine matrices (Derezinski et al, 2016;Dziadosz, 2018;Fraselle et al, 2015;Kučerová et al, 2019;Kwon, Kim, Suh, & In, 2012;Langsi, Ashu-Arrah, Ward, & Glennon, 2017;Luginbühl & Weinmann, 2017;Remane et al, 2015;Sun et al, 2019;West & Rhodes, 2014;Wijemanne, Soysa, Wijesundara, & Perera, 2018;Yen, Dahal, Lavine, Hassan, & Gamagedara, 2018;Yuan et al, 2019). In the group of electromigration techniques, capillary zone electrophoresis (CZE) with contactless conductivity detection (CD) (Grochocki, Markuszewski, & Quirino, 2017), UV detection (Huang, Chen, & Yan, 2012;Pavlíček, Tů ma, Matějčková, & Samcová, 2014;Sidorova & Grigoriev, 2012;Vitali, Goncalves, Rodrigues, Fávere, & Micke, 2017), CD/UV tandem detection (Makrlíková, Opekar, & Tů ma, 2015), or MS detection (DiBattista, Rampersaud, Lee, Kim, & Britz-McKibbin, 2017;Huang et al, 2019;Ramautar, Busnel, Deelder, & Mayboroda, 2012;Wellington et al, 2019;Wild, Shanmuganathan, Hayashi, Potter, & Briz-McKibbin, 2019;Yamamoto, Pinto-Sanchez, Bercik, & Britz-McKibbin, 2019) has been applied for creatinine. Because many different methods are being employed for measuring creatinine, it has become difficult to compare results across different studies and laboratories.…”