Flow-Batch Digital Image Colorimetric System To Zinc Oxide Determination In Ointments

This work proposes a rapid, sensitive and accurate flow-batch digital image colorimetric (FB-DIC) system to zinc oxid determination in ointments. The method was based on the reaction between Zn(II) ions and zincon at pH = 9.0. The Zn(II)-zincon complex was formed and detected in the mixing chamber. It was designed with two opposite glass windows: one for the webcam and other for the ultra-bright LED. Absorbance was calculated by the norm of the vector in the RGB space. The method had a linear range between 1.0-8.2 mg L-1 with R-2 = 0.9998 (n=8) and limit of detection estimated as 5.7 mu g L-1. The relative standard deviation (RSD) and sample throughput were estimated at 0.08 % and 109 samples h(-1), respectively. Ointment commercial samples were analyzed by FB-DIC and the refference method. The results shown no statistically significant difference between them, when was applied the paired t-test at the 95 % confidence level. According to green analytical chemistry (GAC) principles the FB-DIC system can be considered eco-driendly due to its low samples and reagents consumption as its low waste generation.