Field-amplified sample injection combined with capillary electrophoresis for the simultaneous determination of five chlorophenols in water samples

A sensitive method of CZE-ultraviolet (UV) detection based on the on-line preconcentration strategy of field-amplified sample injection (FASI) was developed for the simultaneous determination of five kinds of chlorophenols (CPs) namely 4-chlorophenol (4-CP), 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and 2,6-dichlorophenol (2,6-DCP) in water samples. Several parameters affecting CZE and FASI conditions were systematically investigated. Under the optimal conditions, sensitivity enhancement factors for 4-CP, 2-CP, 2,4-DCP, 2,4,6-TCP, and 2,6-DCP were 9, 27, 35, 43, and 43 folds, respectively, compared with the direct CZE, and the baseline separation was achieved within 5 min. Then, the developed FASI-CZE-UV method was applied to tap and lake water samples for the five CPs determination. The LODs (S/N = 3) were 0.0018-0.019 µg/mL and 0.0089-0.029 µg/mL in tap water and lake water, respectively. The values of LOQs in tap water (0.006-0.0074 µg/mL) were much lower than the maximum permissible concentrations of 2,4,6-TCP, 2,4-DCP, and 2-CP in drinking water stipulated by World Health Organization (WHO) namely 0.3, 0.04, and 0.01 µg/mL, respectively, and thereby the method was suitable to detect the CPs according to WHO guidelines. Furthermore, the method attained high recoveries in the range of 83.0-119.0% at three spiking levels of five CPs in the two types of water samples, with relative standard deviations of 0.37-8.58%. The developed method was proved to be a simple, sensitive, highly automated, and efficient alternative to CPs determination in real water samples.

Spectrophotometric determination of trace carbaryl in water and grain samples by inhibition of the rhodamine-B oxidation

A novel, sensitive, selective and simple kinetic spectrophotometric method has been developed for determination of trace levels of carbaryl based on its inhibitory effect on the oxidation of rhodamine-B by chlorine and bromine released from reaction of potassium bromate with hydrochloric acid in micellar medium. A linear relationship was observed between the inhibitory effect and the concentration of the compound. The absorbance was monitored at the maximum wavelength of 555 nm. The effect of different parameters such as pH, temperature and concentration of rhodamine-B, potassium bromate and surfactant on the reaction were investigated and optimum conditions were established. Under the selected experimental conditions, carbaryl was determined in the range of 0.04-0.4 μg mL(-1). Sandell's sensitivity and molar absorptivity were found to be 0.00055 μg cm(-2) and 3.658×10(5) L mol(-1) cm(-1) respectively. The proposed method was applied satisfactorily for the determination of carbaryl in water and different grain samples. The results were compared with those obtained by reference method and were found to be in agreement.

Monitoring of organic pollutants in coastal waters of the Gulf of Gdańsk, Southern Baltic

This paper presents an overview of changes in organic pollution of coastal waters of the Gulf of Gdańsk (Baltic Sea). Toxic pollutants including volatile organic compounds (VOC), volatile organohalogen compounds (VOX), chlorophenols, phenoxyacids, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were determined in seawater from the Gulf of Gdańsk coastal waters in the period 1996-2001. In the case of the Gulf of Gdańsk, non-conservative behaviour of VOC was observed due to random temporal and spatial of inputs along the Vistula estuary and to the dilution of VOC-enriched river water with seawater. The concentrations of VOX in seawater decreased throughout the period and the concentrations of VOX were in the range of few ng dm(-3) up to 250 ng dm(-3), similar to estuaries elsewhere. The average concentrations of chlorophenols and phenoxyacids were between 0.1 and 6.0 and 0.05 and 2.2 microg dm(-3), respectively. However, remarkably high concentrations of 2,4-dichlorophenol (6 microg dm(-3)) were obtained in samples collected from the Vistula River. Generally concentrations of PCBs did not exceed few ng dm(-3) with the exception of 1999, when all samples exhibited elevated concentrations of PCBs. In addition, higher concentrations of PCBs in the open sea compared to river waters suggested localised inputs. Due to the ability of most organic pollutants to bioaccumulate and biomagnify, especially the persistent organic pollutants, continued monitoring is of crucial importance for the health of marine life in the Gulf of Gdańsk.