Pengembangan Sensor Kolorimetri dalam bentuk Lab on-Tip untuk Mendeteksi Protein pada Urin

Abstract

Protein detection in urine is an important indicator in the early diagnosis of kidney dysfunction. Conventional methods such as acid addition and heating have limitations, so a simpler and more efficient alternative approach is needed. This study aims to develop a colorimetric-based chemical sensor in the form of Lab-on-Tip (LoT) for urine protein detection. The sensor is made from a micropipette tip filled with 7 mm diameter filter paper that has been immobilized with 1000 mg/L tetrabromophenol blue (TBPB) solution and pH 3 buffer. The reaction between the protein and the reagent produces a color change from yellow to green to bluish, which is analyzed using the ImageJ application through the mean green color channel. The results showed that the optimum condition for the reagent volume was 4 µL. The sensor showed good analytical performance with a linear regression equation of y = 0.0255x + 12.844 and a correlation coefficient of 0.9984. The LOD and LOQ values were 5.12 mg/dL and 15.35 mg/dL, respectively. The sensor also demonstrated high selectivity against interfering substances (creatinine, uric acid, and urea), good precision (RSD <5%), and high accuracy with a recovery rate of 99.26% for the standard and 98.58% for the urine sample. Statistical test results showed no significant difference between the LoT method and UV-Vis spectrophotometry. Therefore, the LoT sensor has the potential to be used as an effective and practical alternative method for determining protein levels in urine.