Combination Of Dispersive Solid-phase Extraction Research Articles

Investigation and Quantification of Phthalate Esters in Packaged Milk: A Study in Türkiye

The aim of this study was to explore the concentrations of PAEs (Phthalate esters) in milk in Türkiye. For this purpose, a methodology was developed to quantify eight different PAEs in milk samples using a combination of dispersive solid-phase extraction (dSPE) and Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS). Employing this methodology, the concentrations of PAEs were evaluated in 34 milk samples. Results indicated the presence of PAEs in the milk samples; however, all tested compounds remained within the specific migration limits established by the EU. Among the analyzed PAEs, BBP (Benzyl butyl phthalate) was not detected in any samples, while DMP (di-methyl phthalate) (ND-5.51 µg/L) and DBP (di-butyl phthalate) (ND-7.91 µg/L) exhibited the lowest concentrations. DEHP (bis(2-ethylhexyl)) was identified as the most prevalent plasticizer with a maximum concentration of 41.31 µg/L. In conclusion, this study successfully investigated PAE concentrations in Turkish milk samples using a developed methodology. The results indicated the presence of PAEs within EU-established limits, with DEHP being the predominant plasticizer. Further research and monitoring efforts are crucial to ensure ongoing safety in packaged milk products.

Generic and rapid determination of low molecular weight organic chemical contaminants in protein powder by using ultra-performance liquid chromatography-tandem mass spectrometry

A rapid, simple, and generic analytical method that could simultaneously determine 291 undesirable low molecular weight chemical contaminants from different drug families in protein powder, such as veterinary drugs and pesticides, etc, had been developed. This method comprised the extraction with acetonitrile-dimethyl sulfoxide (DMSO), clean-up through dispersive solid phase extraction (D-SPE) and low temperature filtration, and analysis by ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry at multiple-reaction monitoring mode. Acetonitrile-DMSO was more generic than acetonitrile or methanol for the extraction of large-scale organic chemical contaminants with different polarities in protein powder. Most interferences in the extract were eliminated by the combination of D-SPE and low temperature filtration, which simultaneously provided satisfactory recoveries of both hydrophobic and hydrophilic analytes. In particular, besides the purification function, the sorbent of D-SPE also played an important role in grinding samples to improve extraction efficiency during homogenization. This streamlined approach allowed the processes of extraction and the main purification were carried out in one-step, and dramatically reduced sample preparation turnaround times and solvent consumption. For quantification, matrix-fortified calibration curves showed competent linearity for most of the target compounds with linear regression coefficients (r) higher than 0.9900, except for two analytes. The limits of quantification ranged from 0.1 μg/kg to 50 μg/kg, which was usually sufficient to verify the compliance of products with legal tolerances. The average recoveries for spiked protein powder ranged from 65.6% to 142.2% with associated RSD values between 0.5% and 28.5%. For over 90% of the analytes, the recoveries were between 70% and 120% with RSD values in the range of 1%–15%. Applying this method in routine monitoring programs would drastically reduce both effort and time.

Combination of dispersive solid-phase extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for trace determination of chlorpyrifos in urine samples

ABSTRACT The aim of this study was to develop an effective sample preparation method for the extraction and trace determination of chlorpyrifos pesticide. The method was a combination of dispersive solid-phase extraction (DSPE) and dispersive liquid–liquid microextraction (DLLME) coupled with high-performance liquid chromatography (HPLC). Different factors affecting the performance of the extraction steps in both methods were thoroughly investigated and optimised. They included type and volume of the extractor and disperser solvents in DLLME extraction, as well as type and volume of the elution solvent, type and amount of sorbent in DSPE extraction. The salt addition, pH of solution, and also centrifuging time and speed were taken into account. Under optimal conditions, the enrichment factors were between 177 and 293, and the extraction recoveries were 91–98%. The linear range was 5–400 µg L−1, and limits of detection (LOD) were between 0.9 and 1.8 µg L−1. The relative standard deviations (RSDs) for 100 µg L−1 of chlorpyrifos in urine were in the range of 1.9–3.7% (n = 6). The relative recoveries of the pesticide from urine samples spiked with levels of 10, 100 and 300 µg L-1 were obtained 95.1–101.3%. Compared to other extraction techniques, DSPE–DLLME-HPLC method enjoys some advantages such as the shorter extraction time, high extraction efficiency, and good enrichment factor for the extraction of chlorpyrifos from human urine samples. In addition, it is simple, inexpensive, and highly sensitive, and it can be successfully applied to separation, pre-concentration, and determination of the pesticides in different aqueous samples.

Dispersive solid-phase extraction based on butylamide silica for the determination of sulfamethoxazole in milk samples by capillary electrophoresis

ABSTRACTA new method based on the combination of dispersive solid-phase extraction and capillary electrophoresis is proposed for the determination of sulfamethoxazole in milk samples. Butylamide silica was synthesized and used as extractant. Factors involved in sample treatment method such as: butylamide silica amount, NaOH concentration in methanol, sample volume, and dispersion time were evaluated using a Taguchi parameter design. Under optimal conditions, average recoveries ranged from 73 to 85% with a limit of detection of 0.05 mg L−1 were achieved. The proposed method is a useful technique for cleanup milk samples.

Validation of a streamlined multiclass, multiresidue method for determination of veterinary drug residues in bovine muscle by liquid chromatography-tandem mass spectrometry.

Multiclass, multiresidue methods are becoming increasingly popular in regulatory monitoring programs due to their increased analytical scope and laboratory efficiency. In this work, we report the development and validation of a new high-throughput analytical method to monitor up to 131 veterinary drug residues, representing at least 13 different classes, in bovine muscle. This novel method streamlined sample preparation to <15 min/sample/analyst, or a batch of 40-60 pre-homogenized samples in <3 h/analyst, through the combination of dispersive solid-phase extraction with in-vial filtration (a new technique known as filter-vial d-SPE). The use of an enhanced sensitivity state-of-the-art tandem mass spectrometer led to <10 ng/g limits of quantification for nearly all drug analytes with injection of 0.17 mg of equivalent sample. Positive and negative switching in electrospray ionization was applied to cover all analytes in an 11-min liquid chromatographic separation. In the 3-day validation study, 100 of the drugs met quantification criteria of 70-120% recoveries and Horwitz Ratio ≤1.0, and the remaining analytes could still be screened at regulatory target levels. In the validation study involving >11,400 analyte results for spiked samples, the rate of false negatives for identification purposes was <5%, and no false positives occurred at appreciable concentrations.

Dispersive solid-phase extraction for in-sorbent Fourier-transform infrared detection and identification of nerve agent simulants in analysis for verification of chemical weapon convention

The combination of dispersive solid-phase extraction (DSPE) and Fourier-transform infrared (FTIR) spectroscopy is presented for detection and quantification of markers and simulants of nerve agents. Hydrophilic-lipophilic balance (HLB) sorbent was used for extraction and enrichment of organophosphonates from water. When the extraction efficiency of DSPE was compared with that of conventional solid-phase extraction (SPE), DSPE was more efficient. Extraction conditions such as extraction time, and type and quantity of sorbent material were optimized. In DSPE, extracted analytes are detected and quantified on the sorbent using FTIR as analytical technique. Absorbance in FTIR due to P-O-C stretching was used for detection and quantification. Infrared absorbance of different analytes were compared by determining their molar absorptivities (ε (max)). Quantitative analyses were performed employing modified Beer's law, and relative standard deviations (RSDs) for intraday repeatability and interday reproducibility were found to be in the range 0.30-0.90% and 0.10-0.80% respectively. The limit of detection (LOD) was 5-10μg mL(-1). The applicability of the method was tested with an unknown sample prepared by mimicking the sample obtained in an international official proficiency test.