Screening method for phthalate esters in water using liquid-phase microextraction based on the solidification of a floating organic microdrop combined with gas chromatography-mass spectrometry (original) (raw)
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Journal of the Brazilian Chemical Society, 2016
In this study, a highly sensitive and reliable microextraction method, known as in tube ultrasonic and air assisted liquid-liquid microextraction (IT-UAA-LLME), was developed for the preconcentration of some phthalate esters, such as dimethyl phthalate, diethyl phthalate (DEP), di-butyl-phthalate (DBP), bis(2-ethylhexyl) phthalate (BEHP), butyl benzyl phthalate (BBP), and di n-octyl-phthalate (DNOP), prior to their determination using gas chromatography-mass spectrometry (GC-MS). In this technique, the extraction solvent was dispersed into the aqueous sample solution using an ultrasonic bath. The effects of solvent type, aeration time and salt concentration were investigated. After extraction, an organic solvent was injected into the GC-MS instrument for quantification. Under optimum conditions, the enrichment factors ranged from 100 to 330. The calibration curves showed good linearity (r 2 > 0.99) and limit of detections were obtained in the range of 0.1-2.1 ng mL-1 in the working concentration ranges. The method was successfully applied for determination of six phthalate esters in real samples with complex matrices with relative standard deviation less than 8%, recovery 88-112% and thus, satisfactory results were obtained.
Analytica Chimica Acta, 2012
A novel microextraction technique, air-assisted liquid-liquid microextraction (AALLME), which is a new version of dispersive liquid-liquid microextraction (DLLME) method has been developed for extraction and preconcentration of phthalate esters, dimethyl phthalate (DMP), diethyl phthalate (DEP), di-isobutyl phthalate (DIBP), din -butyl phthalate (DNBP), and di-2-ethylhexyl phthalate (DEHP), from aqueous samples prior to gas chromatography-flame ionization detection (GC-FID) analysis. In this method, much less volume of an organic solvent is used as extraction solvent in the absence of a disperser solvent. Fine organic droplets were formed by sucking and injecting of the mixture of aqueous sample solution and extraction solvent with a syringe for several times in a conical test tube. After extraction, phase separation was performed by centrifugation and the enriched analytes in the sedimented phase were determined by GC-FID. Under the optimum extraction conditions, the method showed low limits of detection and quantification between 0.12-1.15 and 0.85-4 ng mL −1 , respectively. Enrichment factors (EFs) and extraction recoveries (ERs) were in the ranges of 889-1022 and 89-102%, respectively. The relative standard deviations (RSDs) for the extraction of 100 ng mL −1 and 500 ng mL −1 of each phthalate ester were less than 4% for intra-day (n = 6) and inter-days (n = 4) precision. Finally some aqueous samples were successfully analyzed using the proposed method and three analytes, DIBP, DNBP and DEHP, were determined in them at ng mL −1 level.
Solid-phase microextraction of phthalates from water
Journal of Chromatography A, 2001
Solid-phase microextraction (SPME) with six different non-polar and polar fibres was used to extract seven phthalate esters from water samples for analysis by gas chromatography-mass spectrometry. With regard to extraction efficiency and repeatability of the extractions, the 70-mm Carbowax-divinylbenzene fibre was especially suitable for the selected phthalates 21 21
Dispersive liquid-phase microextraction for determination of phthalates in water
Journal of Water Chemistry and Technology, 2015
A technique for phthalate extraction from water samples has been proposed. This technique is based on the preconcentration of target substances using the dispersive liquid-phase microextraction with subsequent determination of these substances using a gas chromatograph with flame ionization detector. Under the optimal conditions of microextraction (involving 0.25 cm 3 of acetonitrile and 0.05 cm 3 of chlo roform in 10% NaCl solution for water sample volume of 8 cm 3 ) concentration factors of phthalates amount to 360-393 at their extraction degree of 91-98%, while the detection limit can reach 3-8 μg/dm 3 . The proposed technique is characterized by a high accuracy and reproducibility.
Analytica Chimica Acta, 2002
Solid-phase microextraction method (SPME) coupled to GC/ECD has been developed and validated for the determination of phthalic acid esters (dimethyl-, diethyl-, din -butyl-, butylbenzyl-, di-2-ethylhexyl-and din -octyl phthalate) in water samples. Two types of coatings (PDMS, PA), altogether four different kinds of fibers have been investigated. Both parameters affecting the partition of analytes between a fiber coating and aqueous phase (i.e. extraction time, extraction temperature, agitation) and conditions of the thermal desorption in a GC injector were optimized. The final SPME method employing the polyacrylate fiber, extraction time 20 min, heating and stirring of the sample enabled the determination of all six phthalates in water samples. The method showed linear response over four orders of magnitude and the limits of quantification of the method ranged between 0.001 and 0.050 g l −1. The repeatability expressed as R.S.D. was in the range 4-10% for the spiking level 7 g l −1 of each analyte. The applicability of the developed SPME method was demonstrated for real water samples.
Microextraction methods for the determination of phthalate esters in liquid samples: A review
Journal of Separation Science, 2015
1,2-Benzenedicarboxylic acid esters, commonly referred to as phthalate esters, form a group of compounds that are mainly used as plasticizers in polymers. Because phthalate esters are not chemically bound to the plastics, they can be released easily from products and migrate into the food or water that comes into direct contact. Due to their widespread use, they are considered as ubiquitous environmental pollutants. Phthalate esters are regarded as endocrine disrupting compounds by means of their carcinogenic effect. Phthalate esters can be analyzed by gas chromatography or highperformance liquid chromatography, however, their sensitivity and selectivity limit their direct use for determination of PEs at very low level of concentrations exist in environmental samples with complex matrices. Therefore a sample pretreatment prior to their analysis is necessary. In this review, the historical development and overview of sample preparation methodologies have briefly been discussed and a comprehensive application of the these methods in combination with different analytical techniques for preconcentration and determination of phthalate esters in various matrices have been summarized. Finally, a critical comparison of the different approaches in terms of enrichment factors achieved, extraction efficiency, precision, selectivity and simplicity of operation is provided.
H ollow-fibre liquid-phase microextraction of phthalate esters from water
A simple and efficient liquid-phase microextraction (LPME) technique using a hollow-fibre membrane, in conjunction with gas chromatography–mass spectrometry has been developed for the extraction and analysis of six phthalate esters in water samples. Parameters such as extraction solvent, agitation of the sample, salt addition and extraction time were controlled and optimised. The developed protocol was found to yield a linear calibration curve in the concentration range 21 21 from 0.02 to 10 mg l for most target analytes and the limits of detection were in the low mg l level, ranging between 21 0.005 and 0.1 mg l. The repeatability of the method varied between 4% and 11%. Under the present experimental conditions, the performance of the method was found comparable to that of solid-phase microextraction (SPME). The advantage of the proposed method over SPME was that it eliminated carry-over of analytes between runs. The applicability of the developed hollow-fibre LPME method and SPME was demonstrated for real water samples. The ability of both microextraction methods to concentrate many organic analytes was demonstrated as both methods allowed the confirmation of the presence of an extra contaminant (ethyl p-ethoxybenzoate) in bottled mineral water samples.
Journal of separation science, 2015
A simple and rapid method using microextraction by packed sorbent coupled with gas chromatography and mass spectrometry has been developed for the analysis of five phthalates, namely, diethyl phthalate, benzyl-n-butyl phthalate, dicyclohexyl phthalate, di-n-butyl phthalate, di-n-propyl phthalate, in cold drink and cosmetic samples. The various parameters that influence the microextraction by packed sorbent performance such as extraction cycle (extract-discard), type and amount of solvent, washing solvent and pH have been studied. The optimal conditions of microextraction using C18 as the packed sorbent were 15 extraction cycles with water as washing solvent and 3×10 μL of ethyl acetate as the eluting solvent. Chromatographic separation was also optimized for injection temperature, flow rate, ion source, interface temperature, column temperature gradient and mass spectrometry was evaluated using the scan and selected ion monitoring data acquisition mode. Satisfactory results were obt...
Journal of Separation Science, 2014
A new approach for the development of a dispersive liquid-liquid microextraction followed by GC with flame ionization detection was proposed for the determination of phthalate esters and di-(2-ethylhexyl) adipate in aqueous samples. In the proposed method, solid and liquid phases were used as the disperser and extractant, respectively, providing a simple and fast mode for the extraction of the analytes into a small volume of an organic solvent. In this method, microliter levels of an extraction solvent was added onto a sugar cube and it was transferred into the aqueous phase containing the analytes. By manual shaking, the sugar was dissolved and the extractant was released into the aqueous phase as very tiny droplets to provide a cloudy solution. Under optimized conditions, the proposed method showed good precision (RSD less than 5.2%), high enrichment factors (266-556), and low LODs (0.09-0.25 g/L). The method was successfully applied for the determination of the target analytes in different samples, and good recoveries (71-103%) were achieved for the spiked samples. No need for a disperser solvent and higher enrichment factors compared with conventional dispersive liquid-liquid microextraction and low cost and short sample preparation time are other advantages of the method.
Microchemical Journal, 2019
In this work, a novel temperature controlled switchable solvent based microextraction method has been developed for the extraction and preconcentration of four PAEs from water samples prior to GC-MS analysis. For the first time, the effect of temperature in the switching of extracting solvent has been studied and the application of cooling/heating processes instead of addition of chemicals in the switchable solvent based microextraction has been used for PAEs extraction. Several parameters including solvent type, solvent volume, temperature of dissolution, temperature of separation, and salt addition are optimized. A theoretical study also has been provided to reveal the effect of cooling/heating effects on the homogenization and separation of phases. The proposed method provided some advantages such as simplicity, using low volumes of inexpensive and less hazardous reagents, rapid extraction and reduced analysis time. For the developed method, LODs and LOQs were obtained in the ranges of 0.03-0.06 and 0.1-0.2 µgL −1 respectively. Also, calibration curves were linear within the range of 0.2-100 µgL −1 for dimethyl phthalate and dibutyl phthalate, and 0.1-100 µgL −1 for diethyl phthalate and dioctyl phthalate. Enrichment factors were found to be in the range of 110.9-116.3. The proposed method was applied for the determination of PAEs in real water samples.