A rapid and simple flow-injection-catalytic spectrophotometric method using stopped-flow technique for determination of trace phenols is described. This methods is based on the catalytic effect of phenols on the reaction of rhodamine B and potassium bromate in sulfuric acid medium. The optimal experimental conditions are obtained by using the controlled and weighed centroid simplex method. The linear range of the determination is 0.60～4．00 mg/L for phenols, and the detection limit is 0.1 mg/L with the sample throughput of 34/h. The relative standard deviation of eleven replicate measurements is less than 2.0%. It has been applied for the determiantion of phenols in waste water with satisfactory results

A rapid and sensitive flow-injection spectrophotometric method was proposed for the determination of metoclopramide. This method was based on the diazotisation of metoclopramide with sodium nitrite in acidic medium and coupling with α-naphthylamine. The optimal experimental condition was obtained by using the simplex optimization method. The linear range was 0.0 ～ 30 mg/L, and the sample throughput was 160 samples h-1. The relative standard deviation of eleven replicate measurements was less than 0.6%. The method was used to determine metoclopramide in tablets and injections. The results were statistically compared with those obtained by pharmacopoeia method.