Optimization and application of the gas-diffusion flow injection method for the determination of chloride

Abstract

A selective and sensitive procedure for the fast and indirect determination of chloride by the gas-diffusion FIA method has been optimized and applied for the determination of chloride in water samples which contained different amounts of the analyte. The examined samples were: seawater, tap water and very pure water from the water-steam system of the power plant "Nikola Tesla B" in Obrenovac. Application of an amperometric detector (model LC-17A; BAS, West Lafayette, USA) enables the detection limit to be decreased down to 0.05 mu mol/dm(3) of chloride, which col responds to 35.5 pg, and adjustment of the acceptor flow rate and direction inside the gas-diffusion unit. In this way the optimized FIA system has excellent repeatability. For 5 mu mol/dm(3) it was found to be 1.11% (n = 5). The throughput of this method is 60 samples per hour.

Selektivan i osetljiv postupak za brzo, indirektno određivanje hlorida gasno-difuzionom metodom otpimizovan je i primenjen za određivanje hlorida u uzorcima voda sa vrlo različitim sadržajem ove vrste: morskoj, vodi za piće i vrlo čistim vodama u sistemu voda-para TE "Nikola Tesna B" u Obrenovcu. Upotreba amperometrijskog detektora tipa LC-17A omogućava snižavanje granice detekcije na 0.05 μmol/dm3 hlorida (što za uzorak zapremine 0.2 cm3 iznosi 35.5 pg) i podešavanje brzine i smera toka u gasno-difuzionoj jedinici. Ovako optimizovan protočni sistem ima odličnu reproduktivnost. Za hloridni standard koncentracije 5 μmol/dm3 relativna standardna devijacija iznosi 1.11 % (n = 5).