Volume Of Extraction Solvent Research Articles

Microwave-assisted extraction of shikimic acid from different morphological parts of water hyacinth (Eichhornia crassipes)

Water hyacinth is a proliferative aquatic weed which destructs biodiversity. Though water hyacinth is a notorious weed, it is a useful resource if used judiciously. One of the important compounds in water hyacinth is shikimic acid, a precursor to produce antiviral drug oseltamivir phosphate. A greener extraction of shikimic acid, phenolic compounds and estimation of antioxidant activity of extract were performed using microwave-assisted extraction from the different morphological parts of water hyacinth. Impact of parameters such as extraction time, solvent volume, temperature and power has been studied. Among various parts of the plant, stem contained higher shikimic acid (2.70%, w/w), leaves had higher total phenolic content (12.15 mg GAE/ g biomass) and extract from stem exhibited the maximum antioxidant activity (75.13%). Further, the optimization of process parameters using central composite design was employed to maximize the yield of shikimic acid (2.61%, w/w) which was achieved at 1.08 min, 45 °C, and 30 mL. Although Ultrasound-assisted extraction has provided a higher yield (3.2%, w/w) of shikimic acid compared to microwave-assisted extraction, the extraction time was reduced by 96% in case of microwave-assisted extraction, thereby reducing energy consumption, utility requirement and carbon emission.

Multivariate response surface methodology assisted modified QuEChERS method for the rapid determination of 39 pesticides and metabolites in medlar

A modified QuEChERS method coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established for residue analysis of 39 pollutants (34 commonly used multi-class pesticides and 5 metabolites) in medlar matrices (fresh, dried, and medlar juice). Samples were extracted using water with 0.1 % formic acid: acetonitrile (5: 10, v/v). The phase-out salts and five different cleanup sorbents (including N-propyl ethylenediamine (PSA), octadecyl silane bonded silica gel (C18), graphitized carbon black (GCB), Carbon nanofiber (C-Fiber) and MWCNTs) were investigated to improve the purification efficiency. The Box-Behnken Design (BBD) study was employed for an optimal solution of the volume of extraction solvent, phase-out salt, and the purification sorbents for the analytical method. The average recoveries of the target analytes in the three medlar matrices ranged from 70 % to 119 % with relative standard deviations (RSDs) of 1.0 %−19.9 %. Screening of market samples (fresh and dried medlars) collected from the major producing regions in China showed that 15 pesticides and metabolites were detected in the samples at concentrations of 0.01–2.22 mg/kg, and none of which exceeded the maximum residue limits (MRLs) set in China. The results showed that the risk of food safety by consumption of medlar products caused by the use of pesticides was low. The validated method could be used for rapid and accurate screening of multi-class multi-pesticide residues in Medlar for food safety.

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.

NADES-assisted sample preparation as a greener alternative for mycotoxins determination in apple-based products

While impressive advancements have been reported in mycotoxin analysis over the last decade, very little has been done to realign the sample treatment to the green sample preparation principles, which are arising more and more relevance in the current analytical chemistry. In this regard, this work proposes the first NADES-assisted sample preparation for the extraction of mycotoxins in food samples.Two protocols using dispersive liquid–liquid microextraction (DLLME) and DLLME with solidification of floating organic drop (DLLME-SFO) assisted with a natural deep eutectic solvent (NADES) were developed and assessed as green sample preparation procedures to extract mycotoxins from apple-based products prior to HPLC-MS/MS analysis. The selected mycotoxins were alternariol, alternariol monomethyl ether, tentoxin and ochratoxin A, which are known to occur in these food matrices. The main variables affecting the extraction efficiency, such as volume of dispersive and extraction solvents, as well as the salting-out effect were evaluated and optimized using a central composite design. In addition, both methodologies were examined and compared in terms of greenness using the newly released metric tool AGREEprep. Due to the use of NADES, the DLLME-SFO method achieved a higher greenness score, and it was selected for further characterization. Matrix-matched calibration curves were used, showing a satisfactory linearity (R2 > 0.99). Limits of detection (LODs) and quantification (LOQs) were below 0.25 and 0.8 µg kg−1, respectively. Recoveries were above 72 % for all the mycotoxins studied in both apple juice and apple puree samples. The validated DLLME-SFO-HPLC-MS/MS method was applied to the analysis of commercial apple juice and puree samples. All the samples analysed were contaminated with at least one mycotoxin with a total concentration ranging from 0.4 to 10.5 µg kg−1.

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.

A Facile and Rapid Strategy for Quantifying PCBs in Cereals Based on Dispersive Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry: A Reference for Safety Concerns in Sustainable Textiles.

Cereals and their derivative products such as starch and cyclodextrin are significant natural materials for sustainable textile processing (e.g., sizing, dispersing, etc.). However, the contamination of cereals with polychlorinated biphenyls (PCBs) is often neglected, which has led to increasing concerns due to the adverse effects on end users. Therefore, monitoring PCBs in cereals is of great importance in preventing health risks. However, high starch, protein, and fat contents make cereals a complicated matrix and can challenge the analysis of PCBs in cereals. This work describes a facile and rapid strategy for quantifying 18 PCBs in cereals that included corn, wheat, and rice through dispersive solid-phase extraction and gas chromatography with mass spectrometry. Importantly, this was the first time that carboxyl-modified, multi-walled carbon nanotubes were incorporated in the detection of PCBs in cereals. The influences of several parameters on the extraction and clean-up efficiency were investigated; these included the type and volume of extraction solvent, sonication time, and the type and dosage of the adsorbent. The matrix effects on quantification were also evaluated. This approach exhibited a better clean-up performance. All the analytes showed weak matrix effects, and thus a solvent standard plot could be prepared for their quantification. Spiking experiments in the selected matrices at three concentration levels from 0.5 to 10 μg/kg resulted in satisfactory recoveries that ranged from 79.2% to 110.5% with relative standard deviations (RSDs; n = 6) less than 10.3%. The limits of detection (LODs) and quantification (LOQs) ranged from 0.04 to 0.1 μg/kg and 0.1 to 0.4 μg/kg, respectively. The practical application of this method was investigated by analyzing actual cereal samples, which demonstrated that the proposed approach was a facile and efficient strategy for PCB determination and provided a reference for the safety evaluation of sustainable textiles. The method also could be generalized to other troublesome samples for testing of multiple PCBs.

Dispersive Liquid - Liquid Microextraction for the Determination of Sulfonamide Residues in Egg Samples

A dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-diode array detection was developed for the extraction and determination of 15 sulfonamide residues in the egg matrix. The effects of various parameters such as the type, volume, and composition of extraction solvent for sample treatment procedure, the type and volume of disperser solvent, centrifugation time, salting-out effect and solution pH were studied, and optimum conditions were established. Linearity was found in the range of 5.4 – 1 000 μg kg-1 with regression coefficients ranging from 0.9918 - 0.9987. The limit of detection (LOD) and limit of quantification (LOQ) values of the proposed method were in the range of 4.3 - 8.0 μg kg-1 and 12.9 - 24.0 μg kg-1, respectively. Satisfactory intra-day and inter-day precision results in the range of 6.3 - 17.5% and 4.8 - 16.8%, respectively, were achieved. The accuracy of the method was acceptable with percentage recovery in the range of 73 - 108% and %RSD values in the range of 1.1 - 16.5%. The proposed method was applied in chicken egg samples obtained from supermarkets, and findings confirmed that the method is feasible to be used for extraction and determination sulfonamide residues in egg and related complex biological matrices.

Determination of Ultra-Trace Amounts of Copper in Environmental Water Samples by Dispersive Liquid-Liquid Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry

A new method of dispersive liquid-liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectrometry (GFAAS) was proposed for the determination of ultra-trace copper. It was based on the reaction of Cu(II) with the laboratory-prepared chelating agent 2-(5-bromo-2-pyridylazo)-5-dimethylaminoaniline (5-Br-PADMA) in a HAc-NaAc buffer solution at pH 5.0 to form stable hydrophobic chelates, which were separated and enriched by DLLME with chlorobenzene (C6H5Cl) and acetonitrile (CH3CN) as extraction and disperser solvents, respectively. The sedimented phase containing the chelates was then determined with GFAAS. Various operating variables that may be affected by the extraction process such as the pH of the solution, the concentration of the chelating agent 5-Br-PADMA, the types and volumes of extraction and disperser solvents, the extraction time, and the centrifugation time were investigated. Under optimum conditions, the calibration curve was linear in the range from 0.02 ng/mL to 0.16 ng/mL of copper with a correlation coefficient of r = 0.9961, and the detection limit was 0.01 ng/mL based on 3Sb. The relative standard deviation for six replicate measurements of 0.05 ng /mL of copper was 3.9%. An enrichment factor (EF) of 110 was obtained. The method has the advantages of low detection limit, high sensitivity, simple operation, less consumption of organic solvents, higher enrichment factor, and environmental friendliness and was applied to the determination of trace copper in environmental water samples with satisfactory results.

Ionic Liquid-Dispersive Micro-Extraction and Detection by High Performance Liquid Chromatography-Mass Spectrometry for Antifouling Biocides in Water.

A simple analytical method was developed and evaluated for the determination of two antifouling biocides using an ionic liquid-dispersive liquid-liquid micro-extraction (IL-DLLME) and a high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis. Irgarol 1051 and Sea-Nine 211 were extracted from deionized water, lake water, and seawater using IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF6]) and ethyl acetate as the extraction solvent and the dispersion solvent. Several factors were considered, including the type and volume of extraction and dispersive solvent, IL amount, sample pH, salt effect, and cooling temperature. The developed method resulted in a recovery range of 78.7-90.3%, with a relative standard deviation (RSD, n = 3) less than 7.5%. The analytes were enriched greater than 40-fold, and the limits of detection (LOD) for two antifouling biocides were 0.01-0.1 μg L-1. The method was effectively applied for the analysis of real samples of freshwater as well as samples of seawater.

Dispersive liquid-liquid microextraction followed by high-performance liquid chromatography as an efficient and sensitive technique for determination of nandrolone and testosterone in human urine

AbstractDispersive liquid-liquid microextraction (DLLME) and high performance liquid chromatography – UV detection was presented for extraction and determination of nandrolone and testosterone in human urines. Chloroform at microliter volume level and acetonitrile were used as extraction and dispersive solvents, respectively. The main advantages of method are high speed, high enrichment factor, high recovery, good repeatability and extraction solvent volume at µL level. The influence of several variables (e.g. type and volume of disperser and extraction solvents, ionic strength, etc.) on the performance of the sample preparation step was carefully evaluated. Under the optimum conditions, the calibration graphs were linear in the range of 5–500 μg L−1 with detection limit of 2.5 μg L−1 for both of them. The relative standard deviation (R.S.D.s) for five replicate measurements of nandrolone and testosterone were 9.4% and 8.8%, respectively. The relative recoveries of nandrolone and testosterone in urine sample at spiking level of 25.0 μg L−1 are ranged between 86.4% and 98%. DLLME combined with HPLC-UV is a fast, simple and efficient method for the determination of nandrolone and testosterone in human urines.

Determination of copper(II) and lead(II) ions in dairy products by an efficient and green method of heat-induced homogeneous liquid-liquid microextraction based on a deep eutectic solvent.

In this study, a new homogeneous liquid-liquid microextraction method using a deep eutectic solvent has been developed for the extraction of Cu(II) and Pb(II) ions in dairy products. Initially, the deep eutectic solvent was synthesized using choline chloride and p-chlorophenol and used as the extraction solvent. The synthesized solvent was soluble in milk at 70 °C and its separation from the sample was performed by decreasing the temperature. By cooling, a cloudy solution was formed due to the low solubility of the solvent at low temperatures. On centrifugation, the fine droplets of the solvent containing the analytes settled at the bottom of the tube by sedimentation. The enriched analytes were determined by flame atomic absorption spectrometry. The effect of some important parameters such as the amount of protein precipitating agent , complexing agent amount, extraction solvent volume, salt addition, pH, and temperature on the extraction efficiency of the method was studied and optimized. Under the optimal conditions, the linear ranges of the method for Cu(II) and Pb(II) ions were obtained in the ranges of 0.10-50 and 0.50-50 μg L-1 with detection limits of 0.04 and 0.18 μg L-1, respectively. The repeatability of the developed method, expressed as relative standard deviation, was determined to be 3.2 and 3.9% for Cu(II) and Pb(II) ions, respectively. Finally, by determining the concentration of Cu(II) and Pb(II) ions in milk, doogh, and cheese samples, the feasibility of the method was successfully confirmed with the extraction recoveries of 95.9 and 92.1% for Cu(II) and Pb(II) ions, respectively.

Quantitative determination of bromochloroacetamide in mice urine by gas chromatography combined with salting-out assisted dispersive liquid-liquid microextraction.

Bromochloroacetamide (BCAcAm) is the main haloacetamide (HAcAm) detected in drinking water in different regions and exhibits strong cytotoxicity and genotoxicity. However, there is no appropriate method for detecting BCAcAm in urine or other biological samples, and thus, the internal exposure level in the population cannot be accurately assessed. In this study, a gas chromatography-electron capture detector (GC-ECD) was combined with salting-out assisted dispersive liquid-liquid microextraction (SA-DLLME) to develop a rapid and robust method for BCAcAm detection in urine of mice continuously exposed to BCAcAm. The factors influencing the pre-treatment procedure, including the type and volume of extraction and disperser solvents, extraction and standing time, and the amount of salt, were evaluated systematically. Under the optimised conditions, the analyte achieved good linearity in the spiked concentration range of 1.00-400.00 μg L-1, and the correlation coefficient was higher than 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.17 μg L-1 and 0.50 μg L-1, respectively. The recoveries ranged from 84.20% to 92.17%. The detection of BCAcAm at three different calibration levels using this method afforded an intra-day precision of 1.95-4.29%, while the inter-day precision range was 5.54-9.82% (n = 6). This method has been successfully applied to monitor the concentration of BCAcAm in mouse urine in toxicity experiments and can provide technical support for assessing human internal exposure levels and health risks in later studies.

DLLME coupled with HPLC-DAD for enrichment of pesticide residues in environmental sediment and soil samples

Sample pre-treatment during determination of pesticides in sediment and soil is difficult due to matrix effects. For this reason, a low density dispersive liquid-liquid microextraction (ld-dllme) was developed for the determination of carbaryl, cynazine, atrazine, and propazine. The experimental parameters that could potentially influence performances of the developed analytical technique including the extraction solvent type and volume, disperser solvent type and volume, extraction and centrifugation time, centrifugation speed, salt concentration, and pH were optimized. The optimum experimental values were found to be 50 mL 1-octanol, 0.6 mL acetonitrile, 5 min extraction time, centrifugation at 3500 rpm for 3 min, 10% NaCl and pH 5. At the optimum conditions, the methods offer good linearity (R2 = 0.998–0.999) for the concentration ranges of 30-800 µg/kg; the detection limit (lod) ranging from 9-24 µg/kg; precision <5.3% rsd, and reproducibility 0.5-5.2% rsd. The accuracy of the method, determined in terms of recovery was found to vary from 74.5-109.7%. Therefore, the developed analytical method could be used for the determination of trace level of pesticides residues in sediment and agricultural soil samples.

Natural Deep Eutectic Solvent-Based Matrix Solid Phase Dispersion (MSPD) Extraction for Determination of Bioactive Compounds from Sandy Everlasting (Helichrysum arenarium L.): A Case of Stability Study.

In the present study, vortex-assisted matrix solid-phase dispersion (VA-MSPD) extraction was used to isolate the major bioactive compounds from H. arenarium. To reduce the negative environmental impact of the conventionally used organic solvents, four different choline chloride-based natural deep eutectic solvents (NADES) were investigated as possible eluents. The most influential VA-MSPD extraction parameters: stationary phase (adsorbent), adsorbent/sample ratio, vortex time, and volume of extraction solvent were systematically optimized. Ultrasound-assisted extraction with 80% MeOH was used as the standard method for the comparison of results. The stability of the obtained extracts was studied over a period of 0 to 60 days at three different temperatures (-18 °C, 4 °C, and 25 °C). All extracts were evaluated both spectrophotometrically (determination of total phenolic content (TPC) and antioxidant activity by ABTS and FRAP assay) and chromatographically (HPLC-UV). NADES based on choline chloride and lactic acid (ChCl-LA) was selected as the most effective extractant, with a determined TPC value of its extract of 38.34 ± 0.09 mg GA/g DW (27% higher than the methanolic VA-MSPD extract) and high antioxidant activity. The content of individual phenolic compounds (chlorogenic acid, dicaffeoylquinic acid isomers, naringenin isomers, and chalcones) in the ChCl-LA extract, determined by HPLC-UV, was comparable to that of the conventionally obtained one. Moreover, the stabilization effect of ChCl-LA was confirmed for the studied compounds: chlorogenic acid, naringenin-4'-O-glucoside, tomoroside A, naringenin-5-O-glucoside, isosalipurposide, and naringenin. The optimum VA-MSPD conditions for the extraction of H. arenarium polyphenols were: florisil/sample ratio of 0.5/1, a vortex time of 2 min, and an elution volume of ChCl-LA of 10 mL.

Biochemical Characterization of Mango Kernel (Mangifera indica) Grown in Côte d’Ivoire and Formulation of Butter for Cosmetic Use

Aims: The peel and the kernel of mangoes of KENT and KEIT varieties, although presenting enormous nutritive and technological potentialities, are considered as waste and, as a result, rejected in nature causing environmental pollution. This study therefore set itself the general objective of contributing to the development of mango by-products (Mangifera indica) by incorporating them into formulations of products for cosmetic use.
 Study Design: Almond butter was obtained from the fresh and dried almonds of two varieties of mangoes (KENT and KEIT).
 Place and Duration of Study: Fruits of mango (KENT and KEIT) varieties at commercial maturity used in this study came from Banco fruit market (Abidjan, Côte d'Ivoire). The tests were carried out at the laboratory of food biochemistry of Nangui Abrogoua University, between May and July 2020.
 Methodology: The mango kernels (Mangifera indica) were extracted and the biochemical characterization of both fresh kernels and almond powders was carried out on parameters such as lipids, ash, fibers, etc. Then, mango kernel powder of KENT with good potential was used for the formulation of butter. Following the control formulation, different formulations were made by reducing volume of extraction solvent (sunflower oil) and varying the amount of beeswax used at 10% and 35% of the mass of macerate used. Finally, physicochemical properties of butter were determined.
 Results: The study showed that mango kernels produced in Côte d’Ivoire, specifically mango kernel powders, were rich in lipids (8-9%), proteins (2-7%), fiber (9-11%), carbohydrates (35-76%), ash (2.99-5.66%), vitamin C (35-104 mg/100g) and many other biomolecules, which made possible the production of butter. The physicochemical properties of butter gave results of acid numbers of 8.24 to 9.03 mg KOH/g oil and saponification of 189.45 to 212.09 mg KOH/g oil. These indices combined with pH (4.6 to 5.2), density (0.3 to 0.91) and color are indicators of the good quality of butter. Finally, the KE 1/3 formulation, with 35% beeswax added, gave the most satisfaction.
 Conclusion: These physical and chemical properties obtained would suggest a finished product of quality and good conservation and good scent pleasant and would have various applications in the cosmetic field in particular in the nutrition of the skin and the hair.

Effervescence assisted dispersive liquid-liquid microextraction for spectrophotometry determination of chromium (VI) in water, tannery effluent, milk, and orange juice samples

In this paper, effervescence-assisted dispersive liquid-liquid microextraction was proposed for selective extraction and preconcentration of Cr (VI) prior to its quantitative determination by UV-Vis spectrophotometry. Before employing the method, Cr (VI) ions available in the samples were complexed with 1,5-diphenylcarbazide in an acidic medium. Experimental parameters influencing the performances of the method including pH, the concentration of the complexing agent, type and volume of both extraction solvent and effervescent agent, stability of the complex, and effect of extraction time were thoroughly studied and optimized. Calibration curve plotted from 0.005-2.0 mg L-1 demonstrated good linearity (R2 = 0.9992). The limits of detection and quantification of the method were 0.001 and 0.005 mg L-1, respectively. The method provided an enrichment factor of 21.4. Precision studies in terms of repeatability, intermediate precision, and reproducibility were conducted at three concentration levels and their RSD values were <6.2. The ruggedness of the method studied at different wavelengths (535-545 nm) had RSD values <3.3. The recoveries of the method were from 83.0-117.6%. Finally, the proposed method was successfully applied for the determination of Cr (VI) from various matrices including tap, well, and river water; tannery effluent; milk; and orange juice samples.

Copper determination in beer by flame atomic absorption spectrometry after extraction and preconcentration by dispersive liquid–liquid microextraction

In this work, an extraction and preconcentration method based on dispersive liquid–liquid microextraction (DLLME) for Cu determination in beer by flame atomic absorption spectrometry (FAAS) was developed. The main parameters that influence the extraction efficiency such as the type and volume of extraction (100 µL CCl4) and disperser (not used) solvents, sample volume (5 mL), pH (no adjustment required) and concentration (2 %, m/v) of sodium diethyldithiocarbamate as chelating agent were studied. The accuracy was evaluated by results comparison with those obtained by microwave-assisted digestion and Cu determination by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectroscopy, as well as by recovery tests. The limits of detection and quantification for Cu determination by the proposed DLLME/FAAS method were 3.2 and 9.1 µg/L, respectively. After method optimization, seven beer samples were analyzed and Cu concentration ranged from 20.6 to 58.8 µg/L. In addition, the preconcentration factor for the DLLME procedure was 50 times and the relative standard deviation (RSD) ranged from 3 to 16 %.

Determination of polycyclic aromatic hydrocarbons in water using dispersive liquid-liquid microextraction-gas chromatography-mass spectrometric

For the extraction of polycyclic aromatic hydrocarbons (PAHs) from water samples, a new sample preparation approach based on dispersive liquid-liquid microextraction (DLLME) was developed. In this procedure, a water sample was injected with a mixture of carbon tetrachloride, CCl4 (extraction solvent), and acetone (disperser solvent) to generate an emulsion in which the PAHs were extracted into fine droplets of extraction solvent. The impacts of several extraction parameters were explored, including extraction solvent type, disperser solvent type, extraction solvent volume, and disperser solvent volume. For phenanthrene and fluoranthene, the calibration curve correlation coefficient (r2) was 0.9993 and 0.9973, respectively. For phenanthrene and fluoranthene, the limits of detection (LODs) were 0.0008 g/mL and 0.0006 g/mL, respectively. For phenanthrene and fluoranthene, the relative standard deviations (RSDs) were 10.69 percent and 9.72 percent, respectively. The analyte recovery rates ranged from 100.5 to 107.8%. Phenanthrene and fluoranthene were discovered in the samples.

RP-HPLC-DAD Analysis of Mitragynine Content in Mitragyna speciosa Korth. (Ketum) Leaf Extracts Prepared Using Ultrasound Assisted Extraction Technique and Their Cytotoxicity

Mitragynine and its congeners are one of the major phytoconstituents present in Mitragyna speciosa Korth. (ketum) leaves and a well-known factor that contributes to ketum’s pharmacological activities. This study describes the usage of a green extraction method to yield botanical leaf extracts of ketum. The leaf extracts were assessed for mitragynine content, total phenolic and flavonoid content, and cytotoxicities. The Ultrasound Assisted Extraction (UAE) method showed a varying dry yield of the extracts (0.22–1.92 g) that were obtained with solvents of variable polarities. However, the mitragynine content was consistent among the organic solvent extracts (7.22–9.40%). This method calls for a minimal extraction solvent volume (solid to solvent ratio, 1:30) and a shorter extraction period (20 min). Of the solvents tested, the methanolic extract showed the highest content of total phenolic (419.50 ± 2.50 GAE mg/g) and flavonoids (177.33 ± 3.00 QE mg/g). The extract was nontoxic towards kidney (HEK-293) and Chang liver (HeLa) cell lines. Analysis via UHPLC-ESI-QTOF-MS/MS made it possible to identify mitragynine congeners, such as mitragynine, paynantheine, and speciociliatine, in the leaves extract. In conclusion, the UAE method using methanol as the extraction solvent provides a noncytotoxic ketum botanical extract for future preclinical and clinical studies.