Automatic Simultaneous Determination of Calcium and Magnesium in Waters by Flow Injection Analysis Using a Photodiode Array Detector and Multicomponent Analysis

Abstract

A new method for the simultaneous determination of calcium and magnesium by flow injection analysis (FIA) using a photometric diode array (PDA) detector and based on the reaction of the two ions with 4-(pyridyl-2-azo)resorcinol (PAR) and the use of multicomponent analysis was developed. The process was controlled via an IBM PC microcomputer running the program DARRAY for instrumental control and data acquisition and processing. The proposed method features a linear determination range of 1–10 mg/L Ca and 1–20 mg/L Mg and a throughput of 70 samples/h, and is only interfered with by Zn(II) and Cu(II), which can also be determined simultaneously with these alkaline earths to avoid their interference.