| Using ionic liquid as extraction solvent, organophosphorus pollutant in water were determined by dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography (HPLC). Parameters including extraction solvent and its volume, disperser solvent and its volume, extraction time and centrifugal time, salt addition, extraction temperature and sample pH were investigated and optimized. Under the optimized conditions, analytical features of the method were evaluated. To investigate the applicability, the proposed method was applied to the analysis of real samples.Using 1-octyl-3-methylimidazolium hexafluorophosphate ([Omim][PF6]) ionic liquid as extraction solvent, organophosphorus pollutant in water were determined by DLLME combined with HPLC. In the DLLME process, a mixture of 35μL [Omim][PF6] (extraction solvent) and 1.0 mL methanol (disperser solvent) was rapidly injected into the 5.0 mL aqueous sample containing the analytes. After centrifuging (5 min at 4000 rpm), the fine droplets of [Omim][PF6] were sedimented in the bottom of the conical test tube. Sedimented phase (5μL) was injected into the HPLC for analysis. Under the optimized conditions, up to 200-fold enrichment factor of analytes and acceptable extraction recovery (>70%) were obtained. The calibration curves were linear in the concentration range of 10.5-1045.0μg/L for parathion, 10.2-1020.0μg/L for phoxim, 54.5-1089.0μg/L for phorate, 27.2-1089.0μg/L for chlorpyifos and 1.0-250.0μg/L for biphenyland and anthracene, respectively, and the coefficients of correlation ranged from 0.9961 to 0.9990. The relative standard deviations for seven replicate experiments were 1.1%-4.7%. The limits of detection calculated at a signal-to-noise ratio of 3 were in the range of 0.1–5.0μg/L for organophosphorus pesticides, 0.0001μg/L for biphenyl and 0.1μg/L for anthracene. The proposed method was applied to the analysis of four different sources water samples (tap, well, rain and Yellow River water). The relative recoveries of spiked water samples are 99.9 % -115.4 %, 101.8 % - 113.7 % and 87. 3 % - 117.6 % at three different concentration levels of 75, 200 and 1000μg/L organophosphorus pesticides, respectively, and 96 %.9 - 112.2 %, 87.0 % - 110.9 % and 94.1% - 110.3 % at three different concentration levels of 25, 100 and 250μg/L phenyl pollutant, respectively.Based the traditional 1-alkyl-3- methylimidazolium ionic liquid, a symmetrical ionic liquid 1,3-dibutylimidazolium hexafluorophosphate ([BBim][PF6]) was synthesized and used as extraction solvent for extraction and preconcentration of organophosphorus pesticides from water and fruit samples by DLLME-HPLC. The optimum conditions are as follows: 50μL [BBim][PF6] as extraction solvent, 0.6 mL methanol as disperser solvent, sample volume: 5 mL ,centrifuging 5 min at 4000 rpm. Under the optimum conditions, enrichment factors were over 300-fold and acceptable extraction recovery (>75%) were obtained. The linearity of the method was obtained in the range of 5-1000μg/L with the correlation coefficients (r2) ranging from 0.9988 to 0.9999. Limits of detection (LODs) were 0.01-0.05μg/L for four analytes. The relative standard deviations at spiking three different concentration levels of 20, 100 and 500μg/L varied from 1.1 % -2.7 %, (n=7), respectively. Three real samples including tap water, Yellow River water and pear spiked at three concentration levels were analyzed and yielded recoveries ranging from 92.7 %-109.1%, 95.0 %-108.2 % and 91.2 %-108.1%, respectively.1-alkyl-3-methylimidazolium room temperature ionic liquids were used as mobile phase additives to separate six inorganic anions (Br-, (NO3)-, (NO2)-, I-, SCN- and (S2O3)2-). The influence of the types of ionic liquid ([Bmim][BF4], [Bmim][Cl], [Bmim][Br], [Emim][Br] and [Emim][BF4]) and their concentrations on retention behavior of inorganic anions was investigated, and the comparison with inorganic salts (NaBF4, NaCl and NaBr) which has the same anions with ILs was also studied. The results indicated that, the k andαof six inorganic anions increase at first and then decrease with the concentration increase of ionic liquid in the mobile phase. With the increase of alkyl of imidazole, the effect on retenation behavior of inorganic anions become more obviously. But the influence of inorganic salts is not obviously. The mechanism was discussed based on the effect of different kind and concentration of ILs and inorganic salts on retention behavior.
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