A New Continuous Flow Injection Analysis Method Coupled with NAG-ADF-300-2 Analyzer for Promethazine-HCl by Cadmium Iodide as a Precipitating Reagent

A highly accurate, simple, sensitive turbidimetric method was introduced for the determination of promethazine-HCl using a homemade NAG-ADF-300-2 system with continuous flow injection analysis system. This method is based on reaction between promethazine-HCl and cadmium iodide (CdI2) in the presence of ammonium acetate to obtain a white precipitate for the ion-pair complex. Turbidity was measured via the attenuation of incident light by precipitated at 0-180°. Optimum parameters were studied to increase the sensitivity for newly developed methodology of promethazine-HCl- cadmium iodide system. The linear dynamic range for the instrument response vs. concentration of promethazine-HCL- was 0.25-25 mmol. L-1 for cell A and 0.1-20 mmol.L-1  for cell B, and limit of quantitative (S/N=10) 360.5574 µg /sample for cell A and 275.5830  µg /sample for cell B respectively with correlation coefficient (r) 0.9961 for cell no. 1 (cell A) and 0.9966 for cell no.2 (cell  B); RSD % was lower than 0.6%. A comparison was made between the newly developed method with UV-Spectrophotometric and turbidimetric method as a classical method by using the standard addition method via the use of t-test at 95% confidence level. In addition, F-test was utilized to predict which of the methods was more precise than other method. The comparison of data revealed that long distance chasing photometer (NAG-ADF-300-2) is the choice with excellent extended detection, wide application and more sensitivity.