Abuzar Kabir

Efficient analysis of selected estrogens using fabric phase sorptive extraction and high performance liquid chromatography-fluorescence detection.

A simple, fast and sensitive analytical method using fabric phase sorptive extraction (FPSE) followed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) has been developed for efficient quantification of biologically important molecules e.g., 17α-ethynylestradiol (EE2), β-estradiol (E2) and bisphenol A (BPA). FPSE is a new sorptive extraction technique that integrates the advantages of permeable sol-gel derived hybrid organic-inorganic sorbents with flexible and permeable fabric substrates, resulting in a highly efficient and sensitive extraction media that can be introduced directly into any kind of fluidic matrix. Various factors affecting the performance of FPSE technique were optimized. The chromatographic separation was carried using mobile phase acetonitrile/methanol/water (30:15:55; v/v) at a flow rate 1.0mL/min on C18 column with fluorescence detection (λex=280nm and λem=310nm). The calibration curves of the target analytes were prepared with good correlation coefficient values (R(2)>0.992). Limit of detection (LOD) values range from 20 to 42pg/mL. The developed method was applied successfully for the analysis of estrogen molecules in urine and various kinds of aqueous samples.

Fast extraction of amphenicols residues from raw milk using novel fabric phase sorptive extraction followed by high-performance liquid chromatography-diode array detection

A simple, sensitive, reliable, and fast analytical method was developed for the simultaneous determination of amphenicols residues in raw milk by combining fabric phase sorptive extraction (FPSE) and high-performance liquid chromatography-diode array detection. FPSE, a new generation green sample preparation technique, efficiently incorporates the advanced and tunable material properties of sol-gel derived microextraction sorbents with the rich surface chemistry of a cellulose fabric substrate, resulting in a flexible, highly sensitive, and fast microextraction device capable of extracting target analytes directly from complicated sample matrices. Due to the strong chemical bonding between the sol-gel sorbent and substrate, the microextraction device demonstrates a very high chemical and solvent stability. Therefore, any organic solvent/solvent mixture can be used as the eluent/back-extraction solvent. Herein, a highly polar polymer coated FPSE media was created using short-chain poly(ethylene glycol) (PEG) and the applicability of this novel microextraction device to extract highly polar amphenicol antibiotics from raw milk was investigated. Due to the intense affinity of amphenicols towards the strongly polar sol-gel PEG-coated FPSE device, absolute recovery of the selected antibiotics residues were found to be 44% for thiamphenicol, 66.4% for florfenicol, and 81.4% for chloramphenicol. The developed method was validated in terms of sensitivity, linearity, accuracy, precision, and selectivity according to European Decision 657/2002/EC. Decision limit (CCα) values were 52.49 μg kg(-1) for thiamphenicol, 55.23 μg kg(-1) for florfenicol, and 53.8 μg kg(-1) for chloramphenicol, while the corresponding results for detection capability (CCβ) were 56.8 μg kg(-1), 58.99 μg kg(-1), and 55.9 μg kg(-1), respectively.

Fabric phase sorptive extraction: A new sorptive microextraction technique for the determination of non-steroidal anti-inflammatory drugs from environmental water samples

Fabric phase sorptive extraction (FPSE) is a new, yet very promising member of the sorbent-based sorptive microextraction family. It has simultaneously improved both the extraction sensitivity and the speed of the extraction by incorporating high volume of sol-gel hybrid inorganic-organic sorbents into permeable fabric substrates. The advantages of FPSE have been investigated for the determination of four non-steroidal anti-inflammatory drugs, ibuprofen, naproxen, ketoprofen and diclofenac, in environmental water samples in combination with gas chromatography-mass spectrometry. Initially, the significance of several parameters affecting FPSE: sorbent chemistry, matrix pH and ionic strength were investigated using a mixed level factorial design (3(1)×2(2)). Then, other important parameters e.g., sample volume, extraction kinetics, desorption time and volume were also carefully studied and optimized. Due to the high sorbent loading on the FPSE substrate in the form of ultra-thin coating and the open geometry of the microextraction device, higher mass transfer of the target analytes occurs at a faster rate, leading to high enrichment factors in a relatively short period of time (equilibrium times: 45-100 min). Under optimal operational conditions, the limits of detection (S/N=3) were found to be in the range of 0.8 ng L(-1) to 5 ng L(-1). The enrichment factors ranged from 162 to 418 with absolute extraction efficiencies varied from 27 to 70%, and a good trueness (82-116% relative recoveries) indicating that the proposed method can be readily deployed to routine environmental pollution monitoring. The proposed method was successfully applied to the analysis of target analytes in two influent and effluent samples from a wastewater treatment plant and two river water samples in Spain.

Stir fabric phase sorptive extraction for the determination of triazine herbicides in environmental waters by liquid chromatography.

Stir fabric phase sorptive extraction (SFPSE), which integrates sol-gel hybrid organic-inorganic coated fabric phase sorptive extraction media with a magnetic stirring mechanism, is presented for the first time. Two flexible fabric substrates, cellulose and polyester were used as the host matrix for three different sorbents e.g., sol-gel poly(tetrahydrofuran), sol-gel poly(ethylene glycol), and sol-gel poly(dimethyldiphenylsiloxane). The new microextraction device has been analytically evaluated using triazine herbicides as model compounds. The factors affecting the extraction efficiency of SFPSE have been investigated and the optimal extraction conditions have been determined. Under these optimum conditions, the limits of quantification (LOQs) for sol-gel poly(ethylene glycol) coated SFPSE device in combination with UPLC-DAD for the analysis of the seven triazine herbicides were in the range of 0. 26-1.50μg/L with precision (relative standard deviation) at 2μg/L concentration ranging from 1.4-4.8% (intra-day, n=5) and 6.8-11.8% (inter-day, n=3). Enrichment factors were found between 444 and 1411 (compared to 2000 theoretical maximum). Absolute extraction recoveries were in the range of 22.2-70.5%. The developed method was applied for the determination of selected triazine herbicides from three river water samples. Relative recoveries of the target analytes, in the range from 75 to 126%, were found to be satisfactory. The combination of SFPSE with LC-MS/MS allows the improvement of the method sensitivity to the range from 0.015μg/L to 0.026μg/L with precision better than 10.8% expressed as relative standard deviation (RSD).

Fabric phase sorptive extraction for the fast isolation of sulfonamides residues from raw milk followed by high performance liquid chromatography with ultraviolet detection.

Fabric phase sorptive extraction (FPSE) is a novel sample preparation technique which utilizes advanced material properties of sol-gel derived microextraction sorbents and the hydrophilic property of the cellulose fabric substrate, resulting in a highly sensitive and fast microextraction device, capable of extracting target analyte(s) from any complex aqueous sample matrices. Due to the low organic solvent consumption, FPSE meets all green analytical chemistry (GAC) criteria. This technique was applied, for the first time, for the determination of sulfonamides residues in milk using a highly polar sol-gel poly(ethylene glycol) (sol-gel PEG) coated FPSE media. The developed HPLC method was validated according to the European Union Decision 2002/657/EC. Decision limit (CCα) values were 116.5 μg kg(-1) for sulfamethazine, 114.4 μg kg(-1) for sulfisoxazole and 94.7 μg kg(-1) for sulfadimethoxine, whereas the corresponding results for detection capability (CCβ) were 120.4 μg kg(-1) for sulfamethazine, 118.5 μg kg(-1) for sulfisoxazole and 104.1 μg kg(-1) for sulfadimethoxine.

Matrix molecularly imprinted mesoporous sol-gel sorbent for efficient solid-phase extraction of chloramphenicol from milk.

Highly selective and efficient chloramphenicol imprinted sol-gel silica based inorganic polymeric sorbent (sol-gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol-gel catalyst. Non-imprinted sol-gel polymer (sol-gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP materials were evaluated as sorbents for molecularly imprinted solid phase extraction (MISPE) of chloramphenicol in milk. The effect of critical extraction parameters (flow rate, elution solvent, sample and eluent volume, selectivity coefficient, retention capacity) was studied in terms of retention and desorption of chloramphenicol. Competition and cross reactivity tests have proved that sol-gel MIP sorbent possesses significantly higher specific retention and enrichment capacity for chloramphenicol compared to its non-imprinted analogue. The maximum imprinting factor (IF) was found as 9.7, whereas the highest adsorption capacity of chloramphenicol by sol-gel MIP was 23 mg/g. The sol-gel MIP was found to be adequately selective towards chloramphenicol to provide the necessary minimum required performance limit (MRPL) of 0.3 μg/kg set forth by European Commission after analysis by LC-MS even without requiring time consuming solvent evaporation and sample reconstitution step, often considered as an integral part in solid phase extraction work-flow. Intra and inter-assay RSD values were less than 13% and accuracy expressed as relative recovery ranged from 85 to 106%.

Comparative study of different fabric phase sorptive extraction sorbents to determine emerging contaminants from environmental water using liquid chromatography-tandem mass spectrometry.

A new sorptive extraction technique, fabric phase sorptive extraction (FPSE), using different coating chemistries: non-polar sol-gel poly(dimethyldiphenylsiloxane) (PDMDPS), medium polar sol-gel poly(tetrahydrofuran) (PTHF), and polar sol-gel poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG triblock) and sol-gel Carbowax 20 M were evaluated to extract a group of pharmaceuticals and personal care products (PPCPs) with wide range of polarity from environmental aqueous samples. Different parameters affecting FPSE such as sample pH, stirring speed, addition of salt, extraction time, sample volume, elution solvent and desorption time were optimized for each sorbent coated FPSE media. Under optimum conditions, FPSE media coated with sol-gel Carbowax 20 M provided the highest absolute recoveries (77-85%) for majority of the analytes with the exception of the most polar ones. Nevertheless, all four sorbents offered better recovery compared to the commercially available coating for stir-bar sorptive extraction based on Ethylene Glycol/Silicone (EG/Silicone). The method based on FPSE with sol-gel Carbowax 20 M media and liquid chromatography-(electrospray ionization) tandem mass spectrometry (LC-(ESI) MS/MS) was developed and validated for environmental water samples. Good apparent recoveries (41-80%), detection limits (1-50 ng L(-1)), repeatability (%RSD<15%, n=5) and reproducibility (%RSD<18%, n=5) were achieved.

Synthesis of benzyl-terminated dendrons for use in high-resolution capillary gas chromatography

Abstract The synthesis, silane functionalization, and facile silica attachment of dendritic monomers containing terminal benzyl groups are presented. For the first time, a simple one-step procedure is described that leads to the in situ creation of a surface-bonded sol-gel dendritic stationary phase on the inner walls of a fused silica capillary; such phases showed unique selectivities in high-resolution capillary gas chromatography.

Determination of androgens and progestogens in environmental and biological samples using fabric phase sorptive extraction coupled to ultra-high performance liquid chromatography tandem mass spectrometry

Androgens and progestogens are two important groups of endocrine disrupting compounds (EDCs) which are implicated to produce severe detrimental impact over aquatic biota, even at very low concentrations of ngL(-1). For this reason, one of the major challenges to analytical chemists is the development of sensitive and selective extraction processes which allow the rapid and green determination of these emerging pollutants at low concentrations in environmental samples. Fabric phase sorptive extraction is a new, highly sensitive, efficient and solvent minimized technique which combine the advantages of sol-gel derived microextraction sorbents and the rich surface chemistry of cellulose fabric substrate. This process has several advantages such as minimum usage of organic solvents, short extraction times, small sample volumes and high analyte preconcentration factors. In this study, an extraction method based on sorptive fabric phase coupled to ultra-high-performance liquid chromatography tandem mass spectrometry detection (FPSE-UHPLC-MS/MS) has been developed for the determination of four progestogens and six androgens in environmental and biological samples. All the parameters involved in the extraction, such as sample volume, extraction and desorption times, desorption solvent volume and sample pH values have been optimized. The developed method provides satisfactory limits of detection (between 1.7 and 264ngL(-1)), good recoveries and low relative standard deviations (below 10% in tap and osmosis water and below 20% in wastewater and urine). Subsequently, the method was used to analyse tap water, wastewater treated with different processing technologies and urine samples. The concentrations of the detected hormones ranged from 28.3 to 227.3 ngL(-1) in water samples and from 1.1 to 3.7μgL(-1) in urine samples.

Development of a fabric phase sorptive extraction with high-performance liquid chromatography and ultraviolet detection method for the analysis of alkyl phenols in environmental samples

A novel analytical method has been developed and validated for the quantification of alkyl phenols in aqueous and soil samples. Fabric phase sorptive extraction, a new sorptive microextraction technique, has been employed for the preconcentration of some endocrine-disruptor alkylphenol molecules, namely, 4-tert-butylphenol, 4-sec-butylphenol, 4-tert-amylphenol, and 4-cumylphenol, followed by high-performance liquid chromatography with ultraviolet detection. Various parameters influencing the fabric phase sorptive extraction performance, namely, extraction time, eluting solvent, elution time and pH of the sample matrix, were optimized. The chromatographic separation was carried out with a mobile phase of acetonitrile/water (60:40 v/v) at an isocratic flow rate of 1.0 mL/min using a reversed-phase C18 column at λmax 225 nm. The calibration curves of target analytes were prepared in the concentration range 5-500 ng/mL with good coefficient of determination values (R2 > 0.992). Extraction efficiency values were 74.0, 75.6, 78.0, and 78.3 for 4-tert-butylphenol, 4-sec-butylphenol, 4-tert-amylphenol, and 4-cumylphenol, respectively. The limits of detection range from 0.161 to 0.192 ng/mL. Subsequently, the new fabric phase sorptive extraction with high-performance liquid chromatography and ultraviolet detection was successfully applied for the recovery of alkyl phenols from spiked ground water, river water, and treated water from a sewage treatment plant, and soil and sludge samples.