Method Development for Determination of EDTA in Water by Using Traditional Split/Splitless Injector-Comparing External and Internal Standard Methods of Quantification

Abstract

Ethylenediaminetetraacetic acid (EDTA) has increasing potential as an environmentally hazardous material. Although EDTA exhibits relatively low acute toxicity, it has been found to be cytotoxic and weakly genotoxic in laboratory animals. In addition, oral exposures can cause reproductive and developmental effects. EDTA is commonly used in wood industry, pulp and paper industry, textile industry, cement industry and food industry. It is also widely used in laundry applications in order to reduce the water hardness and in many cleaning solutions. Due to chemical properties of EDTA (polarity, relatively good solubility in water and chelating ability towards metal ions) it cannot be efficiently removed on common water treatment plants. As a result, the EDTA can be observed in the aquifer downstream near the outputs from water treatment plants of larger industrial entities. Therefore, the reliable monitoring of EDTA in water samples is of great importance. Commonly, the chromatographic methods are used for EDTA analysis with dominance of liquid chromatography coupled with UV-VIS or MS detectors. However, these methods suffer often from the lack of sensitivity towards EDTA at ppt levels. The combination of gas chromatography with high resolution MS can offer significantly lower detection limits (units of ug/l) as well as powerful identification tool. However, the derivatization of EDTA is required when GC-MS is being used. In addition, according to the Czech standard for EDTA determination the Programmed Temperature Vaporising (PTV) injector or cool on-column injection are recommended. In our paper we report on the GC-MS method development for determination of EDTA in water by using traditional split/splitless injector. We compare the external and internal standard methods of EDTA quantification for several different internal standards. The developed method was applied to analysis EDTA in real aqueous samples.