Rapid determination of catecholamines in urine samples by nonaqueous microchip electrophoresis with LIF detection

A method was developed for the rapid separation of catecholamines by nonaqueous microchip electrophoresis ( NAMCE ) with LIF detection, A homemade pump‐free negative pressure sampling device was used for rapid bias‐free sampling in NAMCE , the injection time was 0.5 s and the electrophoresis separation conditions were optimized. Under the optimized conditions, the samples were separated completely in <1 min. The average migration times of the epinephrine ( E ), dopamine ( DA ), and norepinephrine ( NE ) were 34.26, 43.81, and 50.07 s, with an RSD of 1.05, 1.26, and 0.89% ( n = 7), respectively. The linearity of the method ranged from 0.0125 to 2.0 mg/L for E and 0.025∼4.0 mg/L for DA and NE , with correlation coefficients ranging between 0.9978 and 0.9986. The detection limits of E , DA , and NE were 2.5, 5.0, and 5.0 μg/L, respectively. The recoveries of E , DA , and NE in spiked urine samples were between 86 and 103%, with RSD s of 4.5∼6.8% ( n = 5). The proposed NAMCE with LIF detection combined with a pump‐free negative pressure sampling device is a simple, inexpensive, energy efficient, miniaturized system that can be successfully applied for the determination of catecholamines in urine samples.