ANALYSIS OF NITRILOTRIACETIC ACID (NTA), ETHYLENEDIAMINETETRAACETIC ACID (EDTA) AND DIETHYLENETRIAMINEPENTAACETIC ACID (DTPA) IN WATER, PARTICULARLY WASTE-WATER

Two chromatographic techniques can be considered for the detection of the complexing agents NTA, EDTA and DTPA in water: gas chromatography (GC) and liquid chromatography (HPLC). GC is capable of detecting all three compounds in concentrations of as little as 0.001 mg/l. However, this requires a complex and time-consuming sample preparation (enrichment, derivatization). HPLC represents a possible alternative for detecting EDTA and DTPA. Without enrichment it is possible to reach a detection limit of 0.1 mg/l, i.e., while this method is rather less sensitive, it provides results in a much shorter time. If the sample concentrations are high enough, this method is more suitable for conducting routine monitoring of emissions of EDTA and DTPA in waste water. Simple matrices such as surface water or drinking water can be enriched on a pre-column to reduce the detection limit.