Type Of Extraction Solvent Research Articles

Extraction-depended and thermally-modulated physical and chemical properties of powders produced from cranberry pomace extracts

Recovering bioactives from botanical by-products in the form of powders has been attempted through a number of multidirectional approaches. Yet understanding the processing of such plant formulations requires dedicated research owing to the manifold factors shaping the quality of powders. Therefore, the study aimed at production of cranberry powders from pomace extracts and to evaluate how different solvent type, carriers and drying techniques modulate their physico-chemical properties. Freeze- and vacuum drying significantly differentiated samples in terms of physical properties, while the extraction solvent and carrier type had substantial impact on chemical ones. For carrier-added products pomace extraction with acidified 50% ethanol resulted in the highest content of identified phenolics in powders (up to 5.87 g · 100 g−1 dry matter), while 30% acetone in the lowest (on average, 3.94 g · 100 g−1 dry matter). Acetone extraction strengthened the formation of hydroxymethyl-L-furfural that was higher when compared to acidified 50% ethanol, while trace amounts were reported for non-acidified counterpart. Similar observation was made in the case of flavan-3-ols. Addition of carriers during powders production led to the lower hydroxymethyl-L-furfural formation even down to 74% with regard to carrier-free samples. The study confirmed feasibility of managing cranberry pomace into high-value powders in extraction-depended and thermally-modulated quality matter.

Salt saturated dispersive liquid-liquid microextraction of crystal violet from fish and seawater samples based on camphor-thymol based hydrophobic deep eutectic solvent optimized by response surface methodology

A novel salt saturated dispersive liquid-liquid microextraction (SSDLLME) protocol is introduced for the extraction of crystal violet from fish and seawater samples prior to its spectrophotometric determination. As the extracting phase, a hydrophobic deep eutectic solvent based on camphor-thymol (by the mole ratio of 1:1) is employed in the sample. This is the first report of the application of SSDLLME for a dye utilizing deep eutectic solvents as extracting solvent. Saturation by salt significantly increased the performance of the microextraction; i.e. presence of salt in DLLME enhanced signals with more than 42%. Factors influencing the extraction efficiency were evaluated and optimized by both one-variable-at-a-time and response surface methodology methods. The optimum extraction condition were as: pH of sample solution 7.0; type and volume of extraction solvent (organic phase) 60 µL of camphor-thymol (1:1); 500 µL methanol as dispersive solvent; sample volume 10.0 mL; and time and rate of centrifugation 8 min and 9000 rpm, respectively. The suggested microextraction achieved a linear calibration curve in the concentration range of 1.0 to 500.0 µg L−1 with a limit of detection and quantification of 0.28 and 0.97 µg L−1, respectively. Recoveries were also suitable (≥0.97%). The total analysis time was less than 15 min and an enrichment factor of 157 was obtained. This is the first report on successful determination of crystal violet in Chabahar Bay (Oman Sea) and fishes live in the same area.

Effect of Extraction Method and Solvent Type on Total Phenolics Content, Total Flavonoid and Antioxidant Activity of Pegagan Extract (Centella asiatica (Linn.) Urban)

Effect of Extraction Method and Solvent Type on Total Phenolics Content, Total Flavonoid and Antioxidant Activity of Pegagan Extract (Centella asiatica (Linn.) Urban)

Extraction of phenolic and flavonoid compounds and evaluation of their antioxidant activity in saffron anthers (Crocus sativus L.)

Saffron (Crocus sativus L.) is the most expensive spice in the world and rich in a variety of bioactive compounds including phenolic acids, flavonoids, and vitamins. Saffron is used in food, cosmetics, perfumery, and dye industries due to its color, taste, aroma, and medicinal properties. The extraction of bioactive compounds imposes a constant search for economically and environmentally viable extraction strategies for higher yields including the solvent type. The research was carried out to evaluate total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of C. sativus L. anthers using different extraction solvents including ethanol, methanol, and distilled water. The results showed that ethanol was the most effective extraction solvent type exhibiting the highest TPC (7.29 mg GAE g-1 DW), TFC (3.77 mg QE g-1 DW), and antioxidant activity of flavonoids (88%) and ascorbic acid (76.07%). Flavonoids proved to be stronger antioxidants than ascorbic acid, irrespective of solvent type, however the ethanolic extracts showed significantly higher antioxidant activity. A Reverse Phase High-Performance Liquid Chromatography method revealed that gallic acid (3.1 mg g-1), syringic acid (0.2 mg g-1), and vanillic acid (0.13 mg g-1) were the main phenolic compounds detected in the dried anther ethanolic extracts, while quercetin (2.13 mg g-1), pyrogallol (1.73 mg g-1), kaempferol (1.2 mg g-1), rutin (0.2 mg g-1), and tricin (0.1 mg g-1) the main flavonoid compounds. Thus, apart from the spice, constituted by the red stigmas, the production of other flower parts such as the anthers, so far considered agricultural waste can constitute a rich source of bioactive compounds of high antioxidant potential by setting quality standards for new products’ development and ensuring better valorization of saffron’s bioresidues in Mashhad region of Iran.

Ultrasound- and Vortex-Assisted Dispersive Liquid-Liquid Microextraction of Parabens from Personal Care Products and Urine, Followed by High-Performance Liquid Chromatography.

Parabens, which are p-hydroxybenzoic acid esters, are used as preservatives in personal care products, pharmaceuticals, and food because of their antimicrobial activity. However, they are also classified as suspected endocrine disruptors and carcinogens. In the present study, we aimed to optimize an ultrasound and vortex-assisted dispersive liquid-liquid microextraction (DLLME) procedure for the simultaneous extraction of methyl, ethyl, isopropyl, propyl, isobutyl, and butyl parabens from personal care products and urine. The extraction solvent type, extraction solvent volume, disperser solvent volume, sodium chloride concentration, ultrasonication time, and vortex application time were evaluated to obtain optimum recoveries by ultrasound and vortex-assisted DLLME. Parabens were detected using a validated high performanc-liquid chromatography (HPLC) method with fluorescence detection. Method validation was performed by examining linearity, the limit of detection, limit of quantification, accuracy, and precision. The limits of detection and quantification of the HPLC method were between 0.09-0.18 μg/mL and 0.28-0.54 μg/mL, respectively. Precision was examined as the relative standard deviation, which was 0.22-1.81% and 1.12-2.03% for intra- and interday studies. Recovery percentages were higher than 96.00%. Samples of two paraben-free personal care products and synthetic urine were spiked with the analyses at 0.02 μg/mL and were successfully analyzed using the developed procedure with recovery values higher than 82.00%. The proposed procedure provided quantification of selected parabens at 20 ng/mL in analyzed personal care products and urine matrices with good precision and accuracy.

Ultrasound and surfactant-assisted dispersive liquid-liquid microextraction prior to poly(ethylene oxide)-mediated stacking in CE for highly sensitive determination of barbiturates in human fluids.

This study developed a facile, highly sensitive technique for extracting and quantifying barbiturates in serum samples. This method combined ultrasound and surfactant-assisted dispersive liquid-liquid microextraction with poly(ethylene oxide)-mediated stacking in capillary electrophoresis. Factors influencing the extraction and stacking performance, such as the type and volume of extraction solvents, the type and concentration of surfactant, extraction time, salt additives, sample matrix, solution pH, and composition of the background electrolyte, were carefully studied and optimized to achieve the optimal detection sensitivity. Under the optimized extraction (injecting 140μL C2 H4 Cl2 into 1mL of sample with pH 4 (5mM sodium phosphate containing 0.05mM Tween 20 and sonication for 1min) and separation conditions (150mM tris(hydroxymethyl)aminomethane-borate with pH 8.5 containing 0.5% (m/v) poly(ethylene oxide)), the limits of detection (signal-to-noise ratio=3) of five barbiturates ranged from 0.20 to 0.33ng/mL, and the calculated sensitivity improvement ranged from 868- to 1700-fold. The experimental results revealed excellent linearity (R2 >0.99), with relative standard deviations of 2.1%-3.4% for the migration time and 4.3%-5.7% for the peak area. The recoveries of the spiked serum samples were 97.1% -110.3%. Our proposed approach offers a rapid and practical method for quantifying barbiturates in biological fluids.

Comparative Analysis of Phytochemical Constituents and Antioxidant Properties of Aqueous and Ethanol Extracts of Alstonia boonei Stem-Bark

The plant Alstonia boonei is extensively used in traditional medicine because of its therapeutic properties. Over the years, researchers have been looking for the active medicinal agents in different plant species and as such, the type of extraction solvent plays a major role. This study aim to investigate the comparative analysis of phytochemical constituents and antioxidant properties of aqueous and ethanol extracts of A. boonei stem-bark. The stem-bark of A. boonei was collected, dried, pulverized and extracted with ethanol and distilled water using maceration method. The extract was concentrated in a temperature regulated water bath set at 45oC. Qualitative and quantitative phytochemical analysis was carried out in both extracts. Both extracts was also subjected to various antioxidant analytical procedures such as free radical scavenging capacity against 1, 1-diphenyl-2-picrylhydrazyl (DPPH), reducing power, and ferric reducing antioxidant power (FRAP) to determine antioxidant properties. The qualitative phytochemical analysis of both extracts revealed the presence of flavonoids, cardiac glycoside, terpenoids, alkaloids and saponins. However, quantitative studies revealed that proanthocyanidin, flavonoids and total phenol were significantly higher in ethanol extract compared to aqueous extract (p < 0.05). Both extracts exhibited antioxidant activities compared to reference antioxidant (Ascorbic acid). However, the reducing power of the aqueous extract was significantly higher than that of the ethanol extract.This result indicates that aqueous extract of A. booneistem-bark had lower phytochemical constituents but higher antioxidant activity compared to ethanol extract. The result of this study revealed that ethanol may be a better solvent for phytochemical extraction of A. boonei stem-bark.

A Highly Selective Analytical Method Based on Salt-Assisted Liquid-Liquid Extraction for Trace-Level Enrichment of Multiclass Pesticide Residues in Cow Milk for Quantitative Liquid Chromatographic Analysis.

In this study, a simple, inexpensive, selective, and fast salting-out assisted liquid-liquid extraction (SALLE) technique coupled with high-pressure liquid chromatography-diode array detection (HPLC-DAD) was developed for the extraction, preconcentration, and analysis of trace level seven multiclass pesticide residues in pasteurized and raw cow milk samples. The significant factors that affect the extent to which the target analytes are extracted, such as the type of extraction solvent and its volume, the type and concentration of salting-out salts, the pH of the solution, and the extraction time, have been investigated. Under optimum conditions, the correlation coefficient (r2) was obtained within a range of 0.9982-0.9997 for a broad linear range concentration of 2-1500 ng·mL-1. Reliable sensitivity was achieved with limits of detection (LODs) and limits of quantification (LOQs) ranging from 0.58-2.56 ng·mL-1 and 1.95-8.51 ng·mL-1, respectively. While precision with interday and intraday in terms of relative standard deviations (RSDs) was observed in the range of 1.97 - 7.88% and 4.52 - 8.04%, respectively. The results of the precision studies reveal that good repeatability and reproducibility (RSDs <9) were achieved, thus showing a low variability extraction of the developed method. Finally, the proposed and validated approach was effectively used to extract and determine pesticide residues in real milk matrices; however, the target analytes were not detected in all samples.

Rapid separation and determination of six anthocyanins in food and beverage using surface-active ionic liquid-based supramolecular solvent dispersion liquid–liquid microextraction

A simple and efficient method of surface-active ionic liquid-based supramolecular solvent dispersion liquid–liquid microextraction (SAIL-SUPRAS-DLLME) has been developed for the separation and determination of six anthocyanins in food and beverages. The analysis was completed by ultra-high performance liquid chromatography (UHPLC). In this work, a supramolecular solvent formed by the self-assembly of surface-active ionic liquid [EMim][NTF2] and the Tergitol TMN-6 solution were used as the extraction phase in DLPME. Some parameters, including the type and volume of extraction solvent used in SAIL-SUPRAS, pH of the sample phase, concentration of salt, shaking time, centrifugation speed and time were investigated and optimized. The calibration curves for six anthocyanins were all linear with correlation coefficients greater than 0.9994. The intra-day and inter-day precision (RSD) measurements were below 8.1%, while the limits of detection (LOD) for six anthocyanins ranged from 2.11 to 3.27 pg mL−1 (S/N = 3). The proposed method had series of advantages, such as simple, rapid, environmentally friendly preparation of the supramolecular solvent, higher enrichment, excellent sensitivity and selectivity for six anthocyanins. It can be used for the quick analysis and detection of anthocyanins in food analysis.

Extraction solvent selection for Cannabis sativa L. by efficient exploration of cannabinoid selectivity and phytochemical diversity.

Cannabis sativa L. is attracting worldwide attention due to various health-promoting effects. Extraction solvent type is critical for the recovery of bioactive compounds from the plant, especially cannabinoids. However, the choice of solvent is varied and not adequately warranted elsewhere, causing confusion in involved fields. The present work aimed to investigate the effect of extraction solvent on C. sativa (hemp) with regard to cannabinoid recovery and phytochemical profile of the extracts, considering most of the related solvents. The majority of solvents reported for C. sativa (n = 14) were compared using a representative hemp pool. Quantitative results for major and minor cannabinoids were rapidly and reliably obtained using ultrahigh-performance liquid chromatography coupled with photodiode array detection (UPLC-PDA). In parallel, high-performance thin-layer chromatographic (HPTLC) fingerprinting was employed, involving less toxic mobile phase than in relevant reports. Various derivatisation schemes were applied for more comprehensive comparison of extracts. Differential selectivity towards cannabinoids was observed among solvents. MeOH was found particularly efficient for most cannabinoids, in addition to solvent systems such as n-Hex/EtOH 70:30 and ACN/EtOH 80:20, while EtOH was generally inferior. For tetrahydrocannabinol (THC)-type compounds, EtOAc and n-Hex/EtOAc 60:40 outperformed n-Hex, despite its use in the official EU method. Solvents that tend to extract more lipids or more polar compounds were revealed based on HPTLC results. Combining the observations from UPLC quantitation and HPTLC fingerprinting, this work allowed comprehensive evaluation of extraction solvents, in view of robust quality assessment and maximised utilisation of C. sativa.

Application of bio-metal-organic framework-based magnetic dispersive solid phase extraction for the extraction of polycyclic aromatic hydrocarbons from pasteurized milk

This work describes the development of a magnetic dispersive solid phase extraction method based on using bio–metal–organic framework (prepared from vitamin B3 and cobalt salt in water medium) as an efficient sorbent for the extraction of polycyclic aromatic hydrocarbons from milk samples. Briefly, the synthesized sorbent at mg–level is added to the supernatant phase after precipitating the proteins of milk sample and the mixture is vortexed. In the presence of magnetic field, the supernatant is removed and the sorbent particles containing the adsorbed analytes are eluted by using an appropriate organic solvent. The eluted analytes are more enriched using a magnetic ionic liquid–based dispersive liquid–liquid microextraction. After back–extraction of the analytes into n–hexane, the analytes are determined using gas chromatography–mass spectrometry. The experimental variables influencing the suggested method efficiency such as zinc sulfate solution concentration and volume, and vortexing time in proteins precipitating step, sorbent amount, adsorption time, ionic strength, elution solvent type and volume, desorption time, extraction solvent type and volume, and back–extraction solvent type, volume and time in extraction procedure were optimized by one parameter at a time strategy. Under the optimum conditions, low limits of detection (38–78 ng L−1) and quantification (130–260 ng L−1), high extraction recoveries (58–82%) and enrichment factors (145–205), and good precision (relative standard deviations ≤6.1%) were obtained. Finally, the developed method was effectively employed for quantification of polycyclic aromatic hydrocarbons in pasteurized milk samples.

Increase the Efficiency of Dispersive Liquid-Liquid Microextraction (DLLME) and its Use for the Determination of Lead (II) in Aqueous Solutions

A simple, sensitive, and greener method for green extraction and preconcentration of lead from aqueous media and further assay by UV-Vis spectrophotometer has been developed using 1,5 diphenylthiocarbazone (dithizone). Several factors of dispersive liquid-liquid microextraction (DLLME) including the type and volume of extraction and dispersive solvents, shaking time, the concentration of dithizone as a complexing agent, and pH were optimized. Under optimum selected conditions, the limit of detection (LOD), the limit of quantification (LOQ), the linearity range, the relative standard deviation (RSD), and the Enrichment factor (EF) of the proposed method were obtained at 0.007 ppm, 0.025 ppm, 0.01-0.1 ppm, 4.3% (n = 3) and 40, respectively. This proposed method was successfully applied in the analysis of three synthetic water samples and good spiked recoveries over the range of 96.0–98.5% were obtained.

High-throughput screening of multi-pesticide residues in animal-derived foods by QuEChERS-online gel permeation chromatography-gas chromatography-tandem mass spectrometry

Improvements in living standards have led to an increase in the consumption of animal-derived foods. Pesticides may be used illegally during animal breeding as well as meat production and processing for pest control and preservation. Pesticides applied to crops may also be enriched in animal tissues through the food chain, thereby increasing the risk of pesticide residue accumulation in muscles and visceral tissues and endangering human health. China has stipulated maximum residue limits for pesticide residues in livestock and poultry meat and their viscera. Many other major developed countries and organizations, including the European Union, Codex Alimentarius Commission, and Japan, have also set maximum residue limits for these residues (0.005-10, 0.004-10, and 0.001-10 mg/kg, respectively). Research on pretreatment technologies for pesticide residue detection in plant-derived foods is widely available, but insufficient attention has been paid to animal-derived foods. Thus, high-throughput detection technologies for pesticide residues in animal-derived foods are limited. The impurities that can interfere with the detection process for plant-derived foods mainly include organic acids, polar pigments, and other small molecular compounds; by contrast, the matrix of animal-derived foods is much more complex. Macromolecular proteins, fats, small molecular amino acids, organic acids, and phospholipids can interfere with the detection of pesticide residues in animal-derived foods. Thus, selecting the appropriate pretreatment and purification technology is of great importance. In this study, the QuEChERS technique was combined with online gel permeation chromatography-gas chromatography-tandem mass spectrometry (GPC-GC-MS/MS) to determine 196 pesticide residues in animal-derived foods. The samples were extracted with acetonitrile, purified using the QuEChERS technique coupled with online GPC, detected by GC-MS/MS, determined in multiple reaction monitoring mode (MRM), and quantified using the external standard method. The effects of the extraction solvent and purification agent type on the extraction efficiency and matrix removal of the method were optimized. The purification effect of online GPC on the sample solution was investigated. The optimal distillate receiving time was obtained by studying the recoveries of the target substances and matrix effects over different distillate receiving periods to achieve the effective introduction of target substances and efficient matrix removal. Further, the advantages of the QuEChERS technique combined with online GPC were evaluated. The matrix effects of 196 pesticides were assessed; ten pesticide residues showed moderate matrix effects, while four pesticide residues showed strong matrix effects. A matrix-matched standard solution was used for quantification. The 196 pesticides showed good linearity in the range of 0.005-0.2 mg/L, with correlation coefficients greater than 0.996. The limits of detection and quantification were 0.002 and 0.005 mg/kg, respectively. The recoveries of 196 pesticides at spiked levels of 0.01, 0.05, and 0.20 mg/kg were 65.3%-126.2%, with relative standard deviations (RSDs) of 0.7%-5.7%. The proposed method is rapid, accurate, and sensitive; thus, it is suitable for the high-throughput screening and detection of multiple pesticide residues in animal-derived foods.

Effervescence-assisted dispersive liquid-liquid microextraction for extraction and preconcentration of organochlorine pesticides in water samples

ABSTRACT. In this paper, effervescence-assisted dispersive liquid-liquid microextraction method has been developed for the extraction and preconcentration of organochlorine pesticides in water samples before their determination by gas chromatography-mass spectrometry. The method involves in-situ generation of CO2 bubbles to induce dispersion of the extraction solvent in the aqueous sample. Different parameters affecting the extraction efficiency of the method including the type and concentration of the effervescent agents as well as the type and volume of extraction solvent were optimized. Under optimum conditions, matrix matched calibration curves were constructed at eight concentrations ranging from 0.6–4.0 ng/mL showed good linearity with coefficient of determinations of ≥ 0.9961. The limits of detections and quantifications ranged from 0.2–0.4 and 0.6–1.0 ng/mL, respectively. The intra- and inter-day precisions studied at two concentration levels had below 5% relative standard deviation values. Similarly, recoveries investigated at two concentration levels ranged from 80.7–117.4%. The findings demonstrated that proposed method is simple, rapid, and efficient to be used as alternative method for analysis of organochlorine pesticides from environmental water and other similar matrices.&#x0D; &#x0D; KEY WORDS: Effervescence agents, CO2 bubbles, Organochlorine pesticides, Water samples, gas chromatography-mass spectroscopy&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2023, 37(5), 1109-1122. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v37i5.4

Ion-Pair Complex of Trimethoprim with Alizarin Yellow and its Determination and Extraction by LLE and DLLME

For the analysis of trimethoprim medication in its pure form and pharmaceutical formulations, precise and accurate microextraction techniques with UV-Vis measurement have been developed and confirmed. In this study, LLE and DLLME procedures were utilized for the separation, pre-concentration, and evaluation of trimethoprim in pure form and pharmaceutical preparations by UV-Vis spectroscopy at 390 nm. The method was validated and applied to the evaluation of trimethoprim in pharmaceutical formulations. Several experimental factors containing the type of dispersive and extraction solvents and their volumes, pH, temperature, and centrifuging time were carried out. Under the ideal conditions, the procedures were linear in the range of 2–45 and 1-10 mg/L, with a coefficient of determination (R2) of 0.9961 and 0.9992 for LLE and DLLME, respectively. The limit of detection (LOD) was 1.52 and 0.21 mg/L. Recovery of the target analyte in pharmaceutical formulations was 99.3%-104.9%.

A Simple Approach for Fe Determination in Beer by using Dispersive Liquid-Liquid Microextraction and Flame Atomic Absorption Spectrometry

In this work, a new method for Fe extraction and preconcentration from beer by using dispersive liquid-liquid microextraction (DLLME) and determination by flame atomic absorption spectrometry (F AAS) was developed. Although in DLLME the use of an extraction solvent is mandatory (at least in theory), which is combined with a disperser solvent, in this work only the extraction solvent was used. For Fe extraction by DLLME, the type and volume of extraction solvent, sample volume, type of complexing agent, sample pH, salting out effect, and the number of washing cycles after extraction were evaluated. Thus, after optimization, 10 mL of beer, 75 µL of 1,2-dichlorobenzene of extraction solvent, 500 µL of 0.5% (w/v) pyrrolidine ammonium dithiocarbamate (APDC) as complexing agent were used. It is important to mention that pH adjustment, salt addition or washing cycles were no required. For Fe determination after DLLME, an external calibration curve was performed (R2 &gt; 0.99) by direct extracts (reference solutions through DLLME) introduction in the conventional nebulization system of F AAS instrument. The accuracy evaluation was performed by results comparison with those obtained after microwave-assisted digestion (MAD) and Fe determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The Fe concentration in the studied samples ranged from 59.7 to 68.2 µg L-1 and the limit of quantification for DLLME/F AAS method was 9.0 µg L-1. Finally, the proposed method DLLME/F AAS was applied for Fe determination in several beer samples showing simplicity, low operational costs, suitable accuracy (104 to 119%) and precision (better than 13%), opening the possibility for its use in routine analysis for Fe determination in beer.

Development of A Liquid-Phase Microextraction Method for Simultaneous Determination of Parabens in Lipstick Samples at Trace Levels by High-Performance Liquid Chromatography.

The endocrine-disrupting potential of parabens, as well as their relation to cancer, has sparked significant discussions over their impact. Consequently, analyses of cosmetic products are an essential necessity, particularly in terms of human health and safety. In this study, a highly accurate and sensitive liquid-phase-based microextraction method was developed to determine the five parabens at trace levels by high-performance liquid chromatography. All prominent parameters of the method such as extraction solvent type and amount (1,2-dichloroethane/250μL), and dispersive solvent type and amount (isopropyl alcohol/2.0mL) were optimized to enhance the extraction efficiency of the analytes. The mobile phase consisting of 50mM ammonium formate aqueous solution (pH4.0) and acetonitrile (60:40, v/v) was used to elute the analytes at a flow rate of 1.2mLmin-1 in the isocratic mode. Analytical performance of the optimum method for methyl, ethyl, propyl, butyl and benzyl parabens were determined and the analytes recorded detection limit values of 0.78, 0.75, 0.34, 0.33 and 0.75μgkg-1, respectively. Four different lipstick samples were analyzed under optimum conditions of the developed method, and the amount of parabens quantified in the samples using matrix matched calibration standards was in the range of 0.11-1.03%.

Fast surface floating organic droplets based dispersive liquid‐liquid microextraction for trace enrichment of multiclass pesticide residues from different fruit juice samples followed by high performance liquid chromatography–diode array detection analysis

AbstractThis study was designed to enable the development of a simple, fast, and environmentally friendly analytical technique utilizing dispersive liquid‐liquid microextraction based on surface floating organic droplets for selective and quantitative enrichment of trace level pesticide contaminants from different fruit juice samples for subsequent detection by high performance liquid chromatography, combined with a diode array detector. The selective extraction was necessitated in order to isolate the seven multiclass pesticide residues frequently occurring in fruit juice samples. The effects of experimental parameters such as pH of sample solution, type and volume of extraction and dispersive solvents, ionic strength and extraction time were optimized. The optimized method was validated using spiked blank sample and satisfactory results for accuracy, with recoveries ranging from 87.23% to 99.45%, with %relative standard deviation between 1.37 and 8.39, precision in terms of %relative standard deviation ≤ 10.78 and linearity at concentration levels from 3 to 1500 ng/ml, which corresponded with correlation coefficients ≥ 0.998. The limits of detection and the limits of quantification were ranged from 1.3×10−2 to 5.3×10−2 and 4.2×10−2 to 1.8×10−1 μg/L, respectively. At the end, the method was successfully applied to analyze real fruit juice samples and target analytes were not detected in real samples.

Dispersive liquid-liquid microextraction/HPLC techniques for determination of oxytetracycline and doxycycline residues in beef samples: method developments and statistical analysis

A rapid, cost-effective and environment-friendly sample pre-treatment method involving dispersive liquid-liquid microextraction (DLLME) and high-performance liquid chromatography (HPLC) was developed and applied for the extraction of oxytetracycline and doxycycline residues in beef samples (liver, kidney and muscle). Several influencing factors associated with the extraction and separation of these antibiotics residues, such as sample size, type and volume of disperser and extraction solvents, centrifugation speed and time, were optimized using Plackett-Burman design and central composite design, while insignificant factors were fixed at values determined using univariate analysis. Figures of merit of the analytical methodology including the limit of detection (LOD), the limit of quantification (LOQ), accuracy (in terms of average recoveries), precision and calibration functions were established according to the European Union commission decision 2002/657/EC. Linearity, in the range of 5–500 µg/kg, was obtained with regression coefficients ranging from 0.9983 – 0.9999. Inter-day repeatability, intra-day precision, LODs and LOQs obtained were 3.81 – 14.90%, 3.80 – 8.70%, 4.21 – 4.69 µg/kg and 14.02 – 15.65 µg/kg respectively. Samples with detectable drug residues have oxytetracycline being the most commonly detected. The developed method was successfully established and the concentration levels of drug residues detected were lower than the European Union set maximum residue level (MRL).

Dispersive Liquid - Liquid Micro extraction Technique Coupled with High Performance Liquid Chromatography Diode Array Detector for the Determination of Sulfonamides in Water Samples

A dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with diode array detection (DLLME-HPLC-DAD) has been developed for the determination of 15 sulfonamides in water samples. The effects of experimental parameters on the performance of the method such as the type and volume of extraction and disperser solvents, pH of the solution, effect of salt, and centrifugation time were evaluated, and optimum conditions were established. Under these optimum conditions, linearity was found in the range of 2 - 1 000 μg L-1 with regression coefficients better than 0.9990. The limit of detection (LOD) and limit of quantification (LOQ) values were in the range of 0.6 - 7.8 μg L-1 and 1.5 - 8.3 µg L-1, respectively. Intra-day and inter-day precision ranged from 1.5 - 9.7% and from 3.1 - 9.9%, respectively. The accuracy of the method were also evaluated in samples from three different sources of water (river water, groundwater, and tap water) were found to range from 70.5 to 103.9% with %RSD values ranging from 0.5 to 9.8%, with the exception of sulfaguanidine in river water and groundwater where the percentage recovery ranged from 54.3 - 84.9% at the two higher concentration levels (100 and 400 µg L-1).Furthermore, the effect of sample matrix on the extraction of target compounds was evaluated using the relative recovery (%RR) of the samples from three different water sources relative to the ultrahigh purity (UHP) water sample spiked with target analytes, and found in the range of 70.3 - 106.1%.The proposed method was successfully applied to wastewater treatment plant samples and Sulfisoxazole (SSO) was detected in the influent samples in the range of 14.8 - 17.8 µg L-1 with corresponding %RSD, (n = 5) value of 1.6% to 1.9%.The results indicated that the proposed method is effective for the extraction and determination of the sulfonamides in water samples.