Spectrophotometric Determination of Trace Amounts of 2-Methylaziridine in Water and Wastewater Samples after Separation and Preconcentration Using Dispersive Liquid-Liquid Microextraction Technique

2-methylaziridine (propylene imine) is widely used in the production of binding agents in the defence industry. Despite its importance, it is a highly volatile and toxic and can be easily released into the atmosphere during the production and usage causing environmental pollution. The International Agency for Research on Cancer (IARC) has classified it as a Group 2B, possible human carcinogen. So, regarding to the application of 2-methylaziridine in military industry and its toxicity, the determination of its trace amounts is very important in environment samples and industrial wastewater. In this paper, a novel method for preconcentration and spectrophotometric determination of trace amounts of 2-methylaziridine using dispersive liquid-liquid microextraction (DLLME) technique has been developed. This method is based on derivatization of 2-methylaziridine with Folin’s reagent (1,2-naphthoquione-4-sulphonic acid) and preparation of a hydrophobic product with a high molar absorption coefficient which can be preconcentrated and extracted with DLLME technique. Some important parameters of derivatization and microextraction were studied and optimized. Under the optimum conditions, the calibration graph was linear in the range of 10-800 ng mL-1 with detection limit of 5.0 ng mL-1 and relative standard deviation for seven replicate determinations of 2-methylaziridine at 100 ng mL−1 concentration level was calculated to be 1.92%. The proposed method was applied for the determination of 2-methylaziridine in natural water and wastewater samples. In addition, excellent agreement was observed between this proposed method and the standard method.