Implementation of simple and effective fine droplet formation-based spray-assisted liquid phase microextraction for the simultaneous determination of twenty-nine endocrine disruptor compounds and pesticides in rock, soil, water, moss, and feces samples from antarctica using gas chromatography-mass spectrometry.

This study established the simultaneous determination of the selected endocrine-disrupting compounds (EDCs) and pesticides in rock, soil, water, moss, and feces samples collected from the Antarctic region. The spray-assisted droplet formation-based liquid phase microextraction (SADF-LPME) coupled to GC-MS system was developed and validated for the screening and monitoring of 29 selected EDCs and pesticides. Binary solvent system, 1:1 (v/v) dichlormethane: 1,2-dichloroethane mixture was employed as an extraction solvent and sprayed onto sample or standard solutions using a straightforward and practical spray apparatus. The factors affecting the extraction process such as extraction solvent type and ratio, extraction solvent volume (spray repetition), vortexing period, and sample pH were properly optimized. Analytical figures of the merit of the method were recorded under the optimal extraction/chromatographic conditions. The LOD, LOQ, and enhancement factor were in the range of 1.0 to 6.6 ng/g, 3.2 to 22.1 ng/g, and 3.7 to 158.9, respectively. The method demonstrated a good linear working range for all the selected analytes with proper coefficients of determination. The usability and reliability of the microextraction strategy was confirmed using seawater, moss, and soil samples, and the %recoveries were within an acceptable range (> 70%) for all examined samples. The environmental samples collected from the Horseshoe and Faure Islands of the Antarctica region were analyzed to assess the potential pollution of EDCs and pesticides. This method has the potential to be employed for the analysis of EDCs in routine analytical laboratories and for controlling and screening the organic pollutant content of different environmental samples.

Trace nickel determination in seawater matrix using combination of dispersive liquid-liquid microextraction and triethylamine-assisted Mg(OH)2 method.

In order to eliminate the effects of seawater matrix on the precise/accurate determination of elements, new and efficient analytical procedure requires. In this study, co-precipitation method based on the triethylamine (TEA)-assisted Mg(OH)2 was performed to eliminate side-effects of seawater medium on the determination with flame atomic absorption spectrometry (FAAS) prior to the preconcentration of nickel by an optimized dispersive liquid-liquid microextraction (DLLME) method. Under the optimum conditions of the presented method, the limit of detection and quantification (LOD, LOQ) values obtained for nickel were found as 16.1 and 53.8 µg kg-1, respectively. Seawater samples collected from West Antarctic region were used for real sample applications to check the accuracy and applicability of developed method, and satisfying recovery results (86-97%) were obtained. In addition to this, the digital image-based colorimetric detection system and the UV-Vis system were applied to confirm the applicability of the developed DLLME-FAAS method in other analytical systems.

Development and validation of dispersive liquid-liquid microextraction method for the determination of 15 polycyclic aromatic hydrocarbons in 200 Antarctica samples by gas chromatography mass spectrometry.

Antarctica has seen an increase in scientific research and tourism, and anthropogenic activities such as incineration of waste products and fuel combustion for energy and transportation are potential contamination sources to the ecosystem. Polycyclic aromatic hydrocarbons are common products of incomplete combustion of organic compounds and could be among accumulating contaminants in Antarctica. Thus, this study sought to develop a sensitive dispersive liquid-liquid microextraction method for the determination of 15 polycyclic aromatic hydrocarbons by gas chromatography mass spectrometry. Parameters that were relevant to the extraction method were carefully optimized and validated using aqueous standard solutions. The optimum method recorded detection limits in the range of 0.20-6.1 µg/L for the analytes. Spike recovery experiments were carried out on artificial seawater, rock-soil, and moss samples, using matrix matching calibration to mitigate effects of the sample matrices. The samples analyzed included seawater, lake, rock-soil, moss, seaweed, and feces samples all collected from the Horseshoe and Faure Islands in Antarctica. The percent recovery results obtained for the samples spiked at different concentrations ranged between 86 and 115%.

Development of a metal sieve-linked double syringe liquid phase microextraction method for the determination of copper in olive leaf extract samples by flame atomic absorption spectrometry.

This work reports the development of a simple, sensitive and low-cost analytical method for the trace determination of copper. A metal sieve-linked double syringe liquid phase microextraction method was used to preconcentrate copper into measurable quantities for FAAS system. The pressurized mixing offered by the automated syringe system and the sieve connector enhanced surface area for analyte and extraction solvent interaction, this significantly increased the extraction efficiency for copper. There was therefore no need for auxiliary organic solvents as disperser solvents for the extractant dichloromethane. The limits of detection and quantification, linear dynamic range and percent relative standard deviation values calculated for copper under optimum conditions of the method were 1.5 and 5.1 µg L-1, 5.0-500 µg L-1 and 8.4%, respectively. The developed method was successfully employed to determine copper (0.75-8.06 mg kg-1) in unspiked olive leaf samples.

Dispersive solid phase extraction based on reduced graphene oxide modified Fe3O4 nanocomposite for trace determination of parabens in rock, soil, moss, seaweed, feces, and water samples from Horseshoe and Faure Islands.

This study reports an efficient, green, sensitive and simple analytical protocol for trace determination of methyl paraben, ethyl paraben, propyl paraben, butylparaben and benzyl paraben by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). The analytes were preconcentrated using an ultrasonication supported (US) dispersive solid phase extraction (DSPE) method based on reduced graphene oxide (rGO) modified iron nanoparticles (US-Fe3O4@rGO-DSPE). A reversed-phase C18 column and an isocratic elution program comprising of 20 mM phosphate buffer (pH 4.50) and acetonitrile(58:42, v/v) were used to elute and separate the analytes for detection. The limits of detection determined for the analytes were very low and were in the range of 0.02 - 0.16 ng mL-1. The coefficients of determination obtained for the analytes ranged from 0.9973 to 0.9998, and this validated good linearity of the method.Percent relative standard deviations obtained in the range of 2.5 - 10.6% verified the method's high intraday repeatability. Accuracy of the proposed method was assessed with spiking experiments performed on complex sample matrices. Percent recoveries calculated for spiked soil, artificial seawater and seaweed samples were in acceptable ranges of 95 - 121%, 87 - 117% and 85 - 111%, respectively. These figures of merit suggest that HPLC-UV coupled with the US-Fe3O4@rGO-DSPEmethod is suitable for the determination of parabens in Antarctic samples.

Quantification of palladium in wastewater samples by matrix-matching calibration strategy assisted deep eutectic solvent based microextraction.

An efficient, sensitive, and easy deep eutectic solvent based (DESb) liquid phase microextraction (LPME) method was developed to preconcentrate palladium for quantification at trace level by a flame atomic absorption spectrometry (FAAS) system, equipped with a lab made slotted quartz tube (SQT). All parameters of the DESb-LPME-SQT-FAAS system were optimized to lower the detection limit of the system. Using the optimized conditions, quantification and detection limits were obtained as 24.7 and 7.4 µg L-1, respectively, which are compatible with the literature findings. Detection power of the FAAS system was enhanced by almost 50-fold using the optimum method based on LOD comparison. Recovery experiments were also performed with spiked wastewater matrix to examine the applicability/validity of the proposed method. The % recovery results were calculated between 85 and 91%. This established that the applicability of the developed method is high, and determination of this element in complex matrix can be performed accurately using the developed method.

Simultaneous determination of drug active compound, hormones, pesticides, and endocrine disruptor compounds in wastewater samples by GC-MS with direct calibration and matrix matching strategies after preconcentration with dispersive liquid-liquid microextraction.

DLLME was coupled with GC-MS for the simultaneous determination of a drug active compound, hormones, pesticides, and endocrine disruptor compounds with high accuracy and reproducibility in this study. Extraction parameters that affect extraction output including types and volumes of dispersive and extraction solvents, and effect of salt addition were optimized to lower the detection limits for 12 compounds. Under the optimum conditions, LOD and LOQ values were found between 1.99-5.05 and 6.63-16.87 ng/mL, respectively. Spiked recovery tests were also applied to wastewater samples to check the applicability of the method. Matrix matching strategy was used to improve the overall recovery results of the analytes obtained for municipal wastewater. Two different municipal wastewater samples were used in the matrix matching studies. Percent recovery values calculated with the matrix matching experiments were between 85-114%. The results obtained indicated that the developed method could be applied for the determination of the analytes of interest with high accuracy and sensitivity.

A Novel Liquid-Liquid Extraction for the Determination of Sertraline in Tap Water and Waste Water at Trace Levels by GC-MS.

A simple, green and fast analytical method was developed for the determination of sertraline in tap and waste water samples at trace levels by using supportive liquid-liquid extraction with gas chromatography-mass spectrometry. Different parameters affecting extraction efficiency such as types and volumes of extraction and supporter solvents, extraction period, salt type and amount were optimized to get lower detection limits. Ethyl acetate was selected as optimum extraction solvent. In order to improve the precision, anthracene-D10 was used as an internal standard. The calibration plot of sertraline was linear from 1.0 to 1000 ng/mL with a correlation coefficient of 0.999. The limit of detection value under the optimum conditions was found to be 0.43 ng/mL. In real sample measurements, spiking experiments were performed to check the reliability of the method for these matrices. The spiking experiments yielded satisfactory recoveries of 91.19 ± 2.48%, 90.48 ± 5.19% and 95.46 ± 6.56% for 100, 250 and 500 ng/mL sertraline for tap water, and 85.80 ± 2.15% and 92.43 ± 4.02% for 250 and 500 ng/mL sertraline for waste water.

Sensitive Determination of Sertraline in Commercial Drugs and Its Stability Check in Simulated Gastric Juice.

A sensitive analytical method was developed for the determination of sertraline in commercial drug samples by using GC-MS. The selected-ion monitoring mode was used at the most sensitive m/z 274 to obtain a lower detection limit. LOD/LOQ values were obtained as 1.6/5.4 ng/mL for sertraline under the optimum conditions. The calibration plot was linear between 5.0 and 2000 ng/mL with the correlation coefficient of 0.9999. The validated method was successfully applied to three different brands of drug samples for both qualitative and quantitative measurement of sertraline. In this experiment, four replicate extractions were performed for each brand, and the results were compared to the values written on the labels of the drug brands. Spiking experiments were also performed to check the effect of the matrixes on the determination, and it was observed that there was no shift in the retention time of the analyte. In addition, simulated gastric juice experiments were performed to check the stability of sertraline in the stomach for 240 min, and it was observed that there was no change in the structure of the analyte.