This report describes the use of toner-based microzone plates for quantitative determination of glucose in artificial urine and human serum samples using colorimetric detection. The proposed approach has exhibited a linear response for glucose concentration levels from 0 to 10 mmol L , respectively. The glucose analysis in artificial serum samples revealed error lower than 5% in comparison with certified values provided by the supplier. Lastly, the proposed approach has also provided suitable accuracy (92-105%) for glucose measurements in artificial urine samples. Keywords: bioanalytic, clinical assay, disposable device, point-of-care testing, portable instrumentation IntroductionIn the last years, the miniaturization of analytical systems has received considerable attention due to their attractive advantages including low reagent and sample consumption, portability, minimal waste generation, short time analysis, and high-throughput capability. [1][2][3][4][5][6][7] Standard photolithography is one of the main microfabrication technologies allowing the fabrication of microfluidic channels on different platforms including glass, silicon and quartz. Although this technology provides excellent resolution, it is laborious, expensive and time consuming. 8,9 Furthermore, cleanroom facilities and sophisticated instrumentation are required thereby limiting the access to few research groups. For this reason, simpler, cheaper and faster technologies have been developed to promote the rapid spread of miniaturized analytical systems worldwide. [10][11][12] Among the alternative fabrication methodologies, tonerbased techniques offer simplicity and low instrumental requirements, thus making possible their implementation in any laboratory or research center. 13,14 Toner was firstly explored for microfabrication in 2001, when Tan et al. 15 suggested the use of a photocopying machine to create a high-relief master for prototyping of microfluidic devices in poly(dimetilsyloxane) (PDMS) substrate. In 2003, do Lago et al. 16 proposed the direct fabrication of microfluidic devices using a laser printer for the deposition of toner layers on polyester films followed by a thermal lamination for sealing of channels at low temperature. Since this pioneering report, laser printing technology (LPT) has been used to produce microfluidic toner-based analytical devices (µTADs) at very low cost. Due to the advantages associated with the fabrication simplicity and low cost per device, some authors have extended the use of LPT to produce toner-based devices for clinical assays involving the use of portable equipment like cell phone camera, scanner, digital camera and handheld optical microscope for colorimetric measurements. The association of toner-based devices and colorimetric Colorimetric Detection of Glucose in Biological Fluids Using Toner-Based Microzone Plates J. Braz. Chem. Soc. 198 detection is quite attractive for point-of-care (POC) testing due to operational simplicity and low instrumental requirements. Furthermore, the ment...