Liquid Dispersive Liquid-liquid Microextraction Method Research Articles

Application of a reversed-phase ionic liquid dispersive liquid-liquid microextraction method for the extraction and preconcentration of domoic acid from urine samples

A simple and efficient sample extraction and preconcentration method based on reversed-phase ionic liquid dispersive liquid-liquid microextraction (RP-IL-DLLME) had been developed and used to quantify the domoic acid in human urine samples. The analysis was performed by ultra-performance liquid chromatography and photodiode array detection. During the procedure, hydrophilic ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate [C4mim] BF4 as dispersive solvent and NaOH solution was chosen as extraction solvent. Some important parameters in the method were investigated to get high enrichment factors. Under optimal conditions, the linearity of the method was in the range of 0.1–10 ng mL−1 and the correlation coefficient was above 0.9996. The relative standard deviations (RSDs) of the developed methods for intra-day (n = 5) and inter-day (n = 5) precision ranged from 1.9 to 3.9%. Meanwhile, limit of detection (LOD) was 0.03 ng mL−1(S/N = 3) and that of quantification (LOQ) was 0.1 ng mL−1(S/N = 10) with the enrichment factors (EF) being 230. Eventually, the proposed method was successfully applied to the determination of Dominic acid in human urine samples.

Ionic Liquid Dispersive LiquidLiquid Microextraction Method for the Determination of Irinotecan, an Anticancer Drug, in Water and Urine Samples Using UV-Vis Spectrophotometry.

A new, simple, efficient, and environmentally friendly ionic liquid dispersive liquid–liquid microextractionmethod was developed for the determination of irinotecan, an anticancer drug, in water and urine samples using UV-Vis spectrophotometry. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate was used as the extraction solvent, and ethanol was used as the disperser solvent. The main parameters affecting the extraction efficiency, including sample pH, volume of the ionic liquid, choice of the dispersive solvent and its volume, concentration of NaCl, and extraction and centrifugation times, were investigated and optimized. The effect of interfering species on the recovery of irinotecan was also examined. Under optimal conditions, the LOD (3σ) was 48.7 μg/L without any preconcentration. Because the urine sample was diluted 10-fold, the LOD for urine would be 487 μg/L. However, this could be improved 16-fold if preconcentration using a 40 mL aliquot of the sample is used. The proposed method was successfully applied to the determination of irinotecan in tap water, river water, and urine samples spiked with 10.20 mg/L for the water samples and 8.32 mg/L for the urine sample. The average recovery values of irinotecan determined were 99.1% for tap water, 109.4% for river water, and 96.1% for urine.

Temperature-induced aggregation ionic liquid dispersive liquid-liquid microextraction method for separation trace amount of cobalt ion

A simple and rapid temperature induced aggregation micro extraction method based on ionic liquid for extraction and preconcentration of cobalt ions from water samples was proposed. In this investigation small amounts of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF6] and 1-hexyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide [Hmim][Tf2N] (as extractant solvents) were added in a sample solution containing Triton X-114 (as an anti-sticking agent). After centrifuging the cooled solution, analysis was carried out by flame atomic absorption spectrophotometry. Some effective parameters have been optimized. Under the optimum conditions, detection limit of the method was 0.44 ng/mL and the relative standard deviation (RSD) for 100.0 ng/mL cobalt was ±2.3% (n = 7).The calibration curve was linear in the range of 3.0–200.0 ng/mL cobalt and enrichment factor was obtained as 26.5. The applicability of the technique was evaluated by the determination of trace amounts of cobalt in several water samples and synthetic alloys.

Anin situIonic Liquid Dispersive Liquid-Liquid Microextraction Method for the Detection of Pyrethroids by LC-UV in Environmental Water Samples

An in situ ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a new approach for the detection of four pyrethroid pesticides in environmental water samples. The method is fast, simple, accurate and environmentally friendly. The hydrophobic ionic liquid, [C8MIM]-NTf2, formed by the water-soluble ionic liquid [C8MIM]Cl and the ion exchange reagent LiNTf2 was used as the extraction solvent. The experimental parameters affecting the extraction efficiency, including the amount of the IL, the extraction and the centrifugation times and the salt concentration were investigated and optimized using an orthogonal array design (OAD). A suitable molar ratio of LiNTf2 to [C8MIM]Cl on the recoveries of analytes was determined after OAD optimization. The method showed a good linear response in the range of 0.5 to 500 µg L-1 with correlation coefficients (R2) above 0.9998. The relative standard deviation (RSD) varied from 0.6 to 1.9%. The enrichment factor, the limit of detection and recovery ranged from 134 to 153, 0.02 to 0.18 µg L-1 and 89.7 to 95.6%, respectively. For water samples, the RSD ranged from 0.02 to 2.34% and the recovery ranges from 91.4 to 99.9%.

In-situ ionic liquid-dispersive liquid-liquid microextraction method to determine endocrine disrupting phenols in seawaters and industrial effluents

We have evaluated an in-situ ionic liquid-dispersive liquid-liquid microextraction procedure for the determination of six endocrine disrupting phenols in seawaters and industrial effluents using HPLC. The optimized method requires 38 μL of the water-soluble ionic liquid 1-butyl-3-methylimidazolium chloride, and 5 mL of seawater or industrial effluent. After appropriate work-up, a drop (~10 μL) of an ionic liquid is formed that contains the analytes of interest. It is diluted with acetonitrile and injected into the HPLC system. This procedure is accomplished without heating or cooling the solutions. The method is characterized by (a) average relative recoveries of 90.2%, (b) enrichment factors ranging from 140 to 989, and (c) precisions (expressed as relative standard deviations) of less than 11% when using a spiking level of 10 ng mL−1. The limits of detection range from 0.8 ng mL−1 for 4-cumylphenol to 4.8 ng mL−1 for bisphenol-A.