Successive determination of urinary bilirubin and creatinine employing simultaneous injection effective mixing flow analysis

•We assemble a 4-channel simultaneous injection effective mixing flow analysis system.•Dye-forming reactions for urinary bilirubin and creatinine determination are performed in this system.•We conclude the newly proposed flow method is attractive for clinical routine assay.

A novel four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for successive determination of bilirubin and creatinine in urinary samples. The chemical variables and physical parameters in the flow system were optimized for the enhancement of successive analytical performances. The interferences from urine matrices on the determination of bilirubin and creatinine were eliminated to dilute urine samples. The calibration graphs with the optimum conditions were achieved to be in 0.024–5.0 mg L−1 for bilirubin and 2–100 mg L−1 for creatinine. The relative standard deviations (RSDs) at 3 mg L−1 of bilirubin and at 50 mg L−1 of creatinine for 11 runs were 1.5 and 1.0%, respectively. The limits of detections (3σ of blank) for bilirubin and creatinine were 7 µg L−1 and 0.6 mg L−1, respectively. The sample throughput for stepwise detection was 22 h−1. The proposed method was applied to the successive determination of bilirubin and creatinine in urine samples.