Automated analytical procedure using multicommuted flow analysis and organic solvent extraction controlled by an Arduino Due board for photometric determination of zinc in water

摘要

In this study, an automated analytical procedure that utilizes solvent extraction for the photometric determination of zinc in water is described. The procedure involved the reaction of diphenylthiocarbazone (dithizone) with Zn(II) in the alkaline medium and extraction with chloroform. The instrumental setup, combined with flowbatch and multicommuted flow analyses approaches, was designed to facilitate microextraction without using a dispersant organic solvent. Fluid propulsion occurred through two mini peristaltic pumps and a homemade syringe pump. Photometric detection was performed using a homemade LED-based photometer equipped with a flow cell (50 mm in length). The control of the instrumental setup, analytical procedure, and data acquisition algorithm was achieved using an Arduino Due board along with a software developed for this study. After determining the optimal values of the control variables using Zn(II) standard solutions, the effectiveness of the proposed method was evaluated. For this purpose, a set of water samples was analyzed. For assessing accuracy, the samples were also analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). By comparing the paired t-test results of the two analyses, it was observed that at 95% confidence level, there is no significant difference. Other advantageous results of the proposed method were as follows: the linear response range was 10-100 mu gL(-1) (r(2) = 0.9934), the limit of detection was 8.3 mu gL(-1), the coefficient of variation was 3.3% (n = 9), the consumption of chloroform and dithizone was 200 mu L and 4 mu g, respectively, per determination, and the sampling rate was 19 determinations per hour.