Dispersive liquid–liquid microextraction–spectrophotometry combination for determination of Crystal violet in water samples

A new microextraction technique termed dispersive liquid–liquid microextraction (DLLME) was developed. DLLME is a very simple and rapid method for extraction and preconcentration of organic compounds from water samples. In this method, the appropriate mixture of extraction solvent and disperser solvent are injected into the aqueous sample by syringe, rapidly. Therefore, cloudy solution is formed. In fact, it is consisted of fine particles of extraction solvent which is dispersed entirely into aqueous phase. After centrifuging, the fine particles of extraction solvent are sedimented in the bottom of the conical test tube[1]. Crystal violet(CV) is an aromatic organic dye that is soluble in water, and it is used in the textile industry, medicine and aquaculture. This compound is highly toxic to organisms and the aquatic environment, and it can result in death or mutations in organisms that are exposed to it [2] . The use of CV is currently banned in Europe, USA and Japan. Although the use of CV as a fungicide has been banned in Chilean aquaculture, it is still used as an industrial dye and it could also be illegally used in aquaculture. Therefore, this compound is likely discharged into the sewer system, where it then reaches surface waters such as rivers or seas, thereby affecting aquatic life[3]. The effects of various experimental parameters, such as the kind and volume of extraction and disperser solvent, pH of the sample solution, extraction time and salt effect have been studied. In This work, a rapid and effective preconcentration method for extraction of crystal violet was developed by using a dispersive liquid–liquid microextraction (DLLME) prior to uv–vis spectrophotometry[4]. The optimized method exhibited a good linearity (R2 0.998) over the studied range (10-100 mgL−1), illustrating a satisfactory precision level with R.S.D. value 2.1% .