Salting-out Assisted Liquid-liquid Extraction Research Articles

Coconut shell biochar application in liquid-solid microextraction of triazine herbicides from multi-media environmental samples

A rapid, fast, widely applicable liquid-solid microextraction and purification method of triazine herbicides (TRZHs) in muti-media samples using salting-out assisted liquid-liquid extraction (SALLE) combined with self-assembled monolithic spin columns-solid phase micro extraction (MSC-SPME) was developed. Environmentally friendly coconut shell biochar (CSB) was used as the adsorbents of MSC-SPME. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was the separation and determination method. The adsorption kinetics and isotherms were investigated to indicate the interaction between CSB and TRZHs. Several parameters influencing the liquid-solid microextraction efficiency, such as sample pH, salting-out solution volume and pH, sample loading speed, elution speed, elution ratio and volume of eluent were systematically investigated with the aid of orthogonal design. The whole extraction process was operated within 10 min. Under the optimum extraction and determination conditions, good linearities for three TRZHs were obtained in a range of 0.10–200.00 ng mL−1, with linear coefficients (R2) greater than 0.999. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 6.99–11.00 ng L−1 and 23.33–36.68 ng L−1, respectively. The recoveries of the three TRZHs in multi-media environmental samples were ranged from 69.00% to 124.72%, with relative standard deviations (RSDs) lower than 0.43%. This SALLE-MSC-SPME-UPLC-MS/MS method was successfully applied to the determination of TRZHs in environmental and food samples and exhibited the advantages of high efficiency and sensitivity, low cost, and environmental friendliness. Compared with the methods published before, CSB-MSC was green, rapid, easy-operated, and reduced the whole cost of the experiment; SALLE combined MSC-SPME eliminated the matrix references effectively; what's more, the SALLE-MSC-SPME-UPLC-MS/MS method could be applied to various sample without complicated sample pretreatment procedure.

Salting-Out Assisted Liquid-Liquid Extraction for UPLC-MS/MS Determination of Thyroxine and Steroid Hormones in Human Serum and Fish Plasma

Measuring the level of steroid and thyroxine hormones is key to understanding organism health conditions. Liquid chromatography coupled with tandem mass spectrometry has become the method of choice for such hormone analyses in clinical laboratories. Detection of hormones at low levels typically requires a time-consuming sample preparation, such as liquid-liquid extraction followed by solvent evaporation and re-solubilization of the sample extract. Instead, we applied salting-out assisted liquid-liquid extraction (SALLE) for the extraction of thyroxine, testosterone, cortisone, and cortisol from human serum and fish plasma samples. SALLE allowed direct injection of sample extracts. Sodium chloride and ammonium sulfate were evaluated as salting-out reagents together with four different organic solvents. High extraction recovery and reduced matrix interference were achieved by using ammonium sulfate together with 10% methanol in acetonitrile. Limits of quantification were in the range of 0.1–0.2 ng/mL and signal responses were linear (R2 > 0.997) up to at least 100 ng/mL for all hormones. The method was applied for hormone measurements in fish plasma. In conclusion, SALLE combines the simplicity of crude protein precipitation with the high analyte enrichment of a liquid-liquid extraction. Here we have presented it as a novel sample preparation method for clinical laboratories where mass spectrometry is utilized in the field of endocrinology.

Analytical Platform for the Study of Metabolic Pathway of Propyl Propane Thiosulfonate (PTSO) from Allium spp.

The present work is focused on the development of an analytical platform to elucidate the metabolic pathway of PTSO from onion, an organosulfur compound well-known for its functional and technological properties and its potential application in animal and human nutrition. This analytical platform consisted of the use of gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography quadrupole with time-of-flight MS (UHPLC-Q-TOF-MS) in order to monitor volatile and non-volatile compounds derived from the PTSO. For the extraction of the compounds of interest, two different sample treatments were developed: liquid-liquid extraction (LLE) and salting-out assisted liquid-liquid extraction (SALLE) for GC-MS and UHPLC-Q-TOF-MS analysis, respectively. Once the analytical platform was optimised and validated, an in vivo study was planned to elucidate PTSO metabolisation, revealing the presence of dipropyl disulfide (DPDS) in liver samples with concentrations between 0.11 and 0.61 µg g-1. The DPDS maximum concentration in the liver was observed at 0.5 h after the intake. DPDS was also present in all plasma samples with concentrations between 2.1 and 2.4 µg mL-1. In regard to PTSO, it was only found in plasma at times above 5 h (0.18 µg mL-1). Both PTSO and DPDS were excreted via urine 24 h after ingestion.

Development of Salting-out Assisted Liquid-Liquid Extraction for the Determination of Orange I

Development of Salting-out Assisted Liquid-Liquid Extraction for the Determination of Orange I

Development of chromatographic techniques connected with corona and tandem mass spectrometry detection systems for determination of amoxicillin in bovine milk

A new determination method for analysis of antibiotic amoxicillin (AMS) in milk samples was proposed. For isolation of the studied compound solid phase extraction (SPE) and salting-out assisted liquid-liquid extraction (SALLE) were used. The optimal parameters of isolation processes were chosen and matrix effect was evaluated. The liquid chromatographic techniques connected with corona detector (HPLC-CAD) and tandem mass spectrometry system (LC-MS/MS) were used for determination of amoxicillin in SPE and SALLE extracts, respectively. The developed procedures were validated for linearity and precision. The proposed method showed good intra-day and inter-day precision with relative standard deviation values ranging from 1.6% to 4.2%. Limit of detection for SALLE-LC-MS/MS method of AMS determination was lower than the maximum residue limit (MRL: 4 μg kg -1) for amoxicillin in milk samples. The elaborated methods were applied for the monitoring of amoxicillin in different milk samples from regional dairies.

Facile Conversion of the Quinone-Semicarbazone Chromophore of Naftazone into a Fluorescent Quinol-Semicarbazide: Kinetic Study and Analysis of Naftazone in Pharmaceuticals and Human Serum.

Naftazone is a quinone-semi carbazone drug that possesses a strong orange color, and hence it was usually analyzed colorimetrically or by HPLC-UV. However, these methods are not sensitive enough to determine naftazone in biological samples. Naftazone lacks intrinsic fluorescence and does not possess easily derivatizable functional groups. In this contribution, we introduced the first spectrofluorimetric method for naftazone assay through reduction-elicited fluorogenic derivatization through the reduction of its quinone-semicarbazone moiety to the corresponding quinol-semicarbazide derivative by potassium borohydride as a reduction probe. The solvent-dependent fluorescence of the reaction product was studied in various protic and aprotic solvents. Eventually, the fluorescence of the reduced naftazone was measured in 2-propanol at λemission of 350 nm after excitation at λecxitation of 295 nm. The relative fluorescence intensity was linearly correlated to the drug concentration (r = 0.9995) from 10.0 to 500 ng/mL with high sensitivity, where the lower detection limit was 2.9 ng/mL. Hence, the method was effectively applied for naftazone tablets quality control with a mean %recovery of 100.3 ± 1.5, and the results agreed with those of the comparison HPLC-UV method. Furthermore, a new salting-out assisted liquid-liquid extraction (SALLE) method was established for naftazone extraction from human serum, followed by its determination using the developed reduction-based fluorogenic method. The developed SALLE method showed excellent recovery for naftazone from human serum (92.3–106.5%) with good precision (RSD ≤ 6.8%). Additionally, the reaction of naftazone with potassium borohydride was kinetically monitored, and it was found to follow pseudo-first-order kinetics with an activation energy of 43.8 kcal/mol. The developed method’s greenness was approved using three green analytical chemistry metrics.

Development of salting-out extraction methodology for the determination of piroxicam from polymeric based nanocarriers and biological samples

The aim of the present study is to develop the polymeric nanoparticulate drug delivery systems of piroxicam and to evaluate the in-vitro characteristics such as entrapment efficiency, surface morphology, in-vitro drug release performance, etc. For this reason, a novel HPLC methodology was developed for the determination of piroxicam from its bulk form, pharmaceutical preparation, and nanoparticulate delivery systems. Furthermore, the developed formulation was applied to the rats and the biological samples (plasma, liver, heart, spleen, kidney, and lung homogenates) were analyzed by the developed HPLC method following a salting-out assisted liquid-liquid extraction strategy for the first time in the literature. A Kinetex C18 analytical column (150 mm × 4.6 mm i.d., 5 µm) was used as a stationary phase with a 0.8 mL/min flow rate of acetonitrile: phosphate buffer (40:60, v/v), the column oven was adjusted to 40 °C and detection wavelength is set to 360 nm. Developed method were validated as per selectivity, linearity, LOD, LOQ, precision, and accuracy specified in the International Council for Harmonisation guidelines. As a result of the present study, it has been shown that the analysis of piroxicam from the bulk form, pharmaceutical preparation, developed polymeric-based drug delivery system, and biological samples can be successfully performed and no interferences were observed in any matrix. The developed method was also successfully utilized to study the tissue distribution of piroxicam in rats.

Determination of 5-hydroxymethylfurfural using an electropolymerized molecularly imprinted polymer in combination with Salle

Coffee, a beverage with a complex chemical composition, is appreciated for the sensory experience of its taste and aroma. The compound 5-(hydroxymethyl)-2-furfural (HMF) is essential for sensory characterization of the beverage, and is also used in the traceability of its production. In this work, a procedure combining salting-out assisted liquid-liquid extraction (SALLE) and an electropolymerized molecularly imprinted polymer (e-MIP) was developed for the detection and quantification of HMF in coffee samples. The sample preparation step using SALLE employed a combination of acetonitrile and phosphate-buffered saline, in a proportion of 70:30 (ACN:PBS), with addition of 0.02 g of NaCl. The new sensor (e-MIP) was prepared by electropolymerization of p-aminobenzoic acid onto a glassy carbon electrode (GCE) using cyclic voltammetry (CV). Analytical determinations were performed by differential pulse voltammetry (DPV). The linear regression correlation coefficient (r2) for the response was 0.9986. The limits of detection and quantification were 0.372 mg L−1 and 1.240 mg L−1, respectively. The repeatability and reproducibility values obtained were 6 and 10%, respectively. The recoveries for three concentration levels were between 97 and 101%. Analyses of different coffee samples showed that the HMF concentrations varied from 261.0 ± 41.0 to 770.2 ± 55.9 mg kg−1 in powdered coffee samples, and from 1510 ± 50 to 4445 ± 278 mg kg−1 in instant coffee samples. The advantages of this procedure, compared to other methods described in the literature, are its simplicity, easy operation, good selectivity and sensitivity, low cost, and minimal use of organic solvents.

Chemical Composition, Anti-Breast Cancer Activity and Extraction Techniques of Ent-Abietane Diterpenoids from Euphorbia fischeriana Steud.

Ent-abietane diterpenoids are the main active constituents of Euphorbia fischeriana. In the continuing search for new anti-breast cancer drugs, 11 ent-abietane diterpenoids (1–11) were isolated from E. fischeriana. The structures of these compounds were clearly elucidated on the basis of 1D and 2D NMR spectra as well as HRESIMS data. Among them, compound 1 was a novel compound, compound 10 was isolated from Euphorbia genus for the first time, compound 11 was firstly discovered from E. fischeriana. These compounds exhibited varying degrees of growth inhibition against the MCF-10A, MCF-7, ZR-75-1 and MDA-MB-231 cell lines in vitro. The experimental data obtained permit us to identify the roles of the epoxy group, hydroxyl group and acetoxyl group on their cytotoxic activities. Extraction is an important means for the isolation, identification, and application of valuable compounds from natural plants. To maximize yields of ent-abietane diterpenoids of E. fischeriana, 17-hydroxyjolkinolide B, jolkinolide B, 17-hydroxyjolkinolide A and jolkinolide A were selected as quality controls to optimize the salting-out-assisted liquid–liquid extraction (SALLE) by response surface methodology (RSM). The optimized conditions for SALLE were 0.47 g sodium dihydrogen phosphate, 5.5 mL acetonitrile and 4.5 mL water at pH 7.5. The experimental values of 17-hydroxyjolkinolide B, jolkinolide B, 17-hydroxyjolkinolide A and jolkinolide A (2.134, 0.529, 0.396, and 0.148 mg/g, respectively) were in agreement with the predicted values, thus demonstrating the appropriateness of the model.

High-throughput salting-out assisted liquid-liquid extraction using a 3D printed device and its application in the quantification of ibrutinib and its metabolite PCI-45227 in human serum

Liquid–liquid extraction methods are widely used for sample treatment in bioanalysis, although their implementation poses a common speed-limiting step in the analytical process when fast separation and detection methods such as UHPLC-MS are used. This study aimed to develop high-throughput salting-out assisted liquid–liquid extraction on a 96-well plate in combination with fast LC-MS analysis of ibrutinib and its active metabolite PCI-45227 (dihydrodiol ibrutinib) in human serum. A specially designed 3D printed extraction device developed in our laboratory allowed for the precise and rapid collection of the organic phase from the 96-well plate using a multichannel pipette, without the risk of aspiration of the bottom aqueous layer. The application of this device significantly accelerated sample preparation and allowed the processing of up to 96 samples in 1 h. The method was successfully validated according to EMA guidelines in the concentration range of 0.1–200 ng/mL for both analytes, providing lower limit of quantification at 100 pg/mL. The intra-day accuracy for IBT was in the range of − 1.67–5.67 %, while the inter-day accuracy was in the range of 0.20–6.90 %. The intra-day precision for IBT was in the range of 3.20–4.37 % and 3.13–4.73 % for the inter-day measurement. PCI-45227 showed intra-day accuracy in the range of − 11.2–3.71 % and the inter-day accuracy in the range of − 5.76–0.92 %. The intra-day precision for PCI was in the range of 3.49–7.64 % and 3.63–8.61 % for the measurement between days.In addition to increasing the speed of sample preparation, this method also offers low consumption of the sample and extraction solvent and can be utilized for other similar small-volume in-well plate extractions where organic solvents of lower density than water are used. The method was successfully applied to the analysis of serum samples (n = 5) of patients with chronic lymphoblastic leukaemia at the trough level (ibrutinib concentration range: 1.63–3.78 ng/mL, PCI-45227 concentration range: 1.84–14.02 ng/mL) and 2 h postdose (ibrutinib concentration range: 7.34–89.0 ng/mL, PCI-45227 concentration range: 5.64–124 ng/mL).

Chemometric optimization of salting-out assisted liquid–liquid extraction (SALLE) combined with LC-MS/MS for the analysis of carvedilol enantiomers in human plasma: Application to clinical pharmacokinetics

Carvedilol is a commonly used antihypertensive whose oral absorption is limited by low solubility and significant first-pass metabolism. This work aimed to apply chemometrics for the optimization of a salting-out assisted liquid–liquid extraction (SALLE) combined with LC-MS/MS to analyze carvedilol enantiomers in plasma samples. Method development and validation were driven for application in pharmacokinetic studies. Parameters that influence the efficiency of SALLE were evaluated using a fractional factorial 24–1 design with 4 factors and a central composite design was used to evaluate the optimal extraction condition. Carvedilol enantiomers and the internal standard lidocaine were separated on an Astec® Chirobiotic® V column and a mixture of methanol:ethanol (90:10, v/v) with 0.02% diethylamine and 0.18% acetic acid as mobile phase. The positive ion mode on electrospray ionization was used to monitor the transitions of m/z 407 > 100 and 235 > 86 for carvedilol enantiomers and lidocaine, respectively. Acetonitrile and ammonium acetate solution were selected for sample preparation by SALLE. Surface graphs and the desirability test were used to define the optimized SALLE conditions which resulted in 93% recovery for both carvedilol enantiomers. The method was linear in the range of 0.5 to 100 ng/mL in plasma, with a lower limit of quantification of 0.5 ng/mL. Within-run and between-run precision (as the relative standard deviation) were all < 9.74% and accuracy (as relative error) did not exceed ± 10.30%. Residual effect and matrix effect were not observed. Carvedilol enantiomers were stable in plasma under the storage, preparation, and analysis conditions. The validated method was successfully applied to analyze carvedilol in plasma samples from patients previously submitted to a Roux-en-Y gastric bypass surgery treated with a single oral dose of 25 mg racemic-carvedilol. Higher plasma concentrations were observed for (R)-(+)-carvedilol when compared to (S)-(-)-carvedilol in two patients post-bariatric surgery.

Spatial distribution, ecological and health risk assessment of organophosphorus pesticides identified in the water of Naseri artificial wetland, Iran

Agricultural development is inevitable to meet the growing need for food. But along with this development, there are unintended and undesirable consequences for human life and the environment that need, found a solution and corrected. One of the most important adverse consequences of agricultural development is the pollution of surface and groundwater resources, which results from various factors such as soil erosion and improper use of different pesticides. This study aimed to conduct an environmental monitoring program in Naseri wetland to determine the concentrations of organophosphorus pesticides (OPPs) in water samples and also to evaluate the potential risks (ecological and health risk assessment) of these pesticides. The salting-out assisted liquid-liquid extraction method was used to extract pesticides. The residual concentrations of OPPs evaluated by gas chromatography/mass spectrometry (GC/MS). In this study, the ecological risk of OPPs calculated for wetland ecosystem, based on the acute risk quotient (RQi) formula with maximum (RQmax), mean (RQmean), and mixture (RQmix) concentrations of organophosphorus pesticides in the wetland water. Also, to assess the health risk of consuming contaminated fish with organophosphate pesticides, the potential non-carcinogenic and carcinogenic risks were determined by the hazard quotient (Index) (HQ, HI) and incremental lifetime cancer risk (ILCR) indices, respectively. The mean ± SD concentration of OPPs (Chlorpyrifos, Malathion, Ethion, Dichlorvos, Trifluralin and Diazinon) in samples of wetland water ranged from 0.14 ± 0.08 to 0.35 ± 0.12 and 0.054 ± 0.06 to 0.2 ± 0.1 (μg/L) in summer and autumn, respectively. The mean ± SD of OPPs in fish varied from 0.68 ± 0.86 to 3.94 ± 2.7 (μg/kg). Overall, the concentrations of pesticides in all water and fish samples were below the maximum residue limit (30 μg/kg) during the study period, according to the Environmental Protection Agency (EPA) and the World Health Organization (WHO). The results of acute risk quotient were in summer (RQmax = 3.49E-4 to 0.067, RQmean = 5.8E-5 to 0.029, RQmix = 0.139-0.026, 0.018-3.42E-3) and autumn (RQmax = 8E-4 to 0.051, RQmean = 7.74E-6 to 0.018 RQmix = 0.1–0.013, 6E-3- 1.5E-3). The non-carcinogenic and carcinogenic risk indexes due to fish consumption for adults and children were (HQ = 0.026-4.68E-4, HI = 0.041, ILCR = 1.7E-7) and (HQ = 1.85E-3-1.3E-5, HI = 0.041, ILCR = 5.55E-8), respectively. The risk of OPPs was generally low. But cumulative risk (pesticide mixtures), should not be ignored.

Quantitative extraction of multiclass antibiotic residues in cow milk utilizing salting-out assisted liquid-liquid extraction followed by liquid chromatographic determination

ABSTRACT The salting-out assisted liquid–liquid extraction (SALLE) method with the liquid chromatography ultraviolet-visible detector (LC-UV) has been developed and validated for the simultaneous determination of seven antibiotic compounds of five different therapeutic classes (β-lactams), amoxycillin, ampicillin, penicillin G, (sulphonamides), sulfamethoxazole, (aminoglycosides) gentamicin, (fluoroquinolones) ciprofloxacin and (macrolide) erythromycin, in the cow milk samples. The LC conditions for separation of the selected antibiotic compounds were achieved with the reversed phase isocratic elution. The mobile phase consisted of 0.05 M Na2HPO4, acetonitrile and methanol (70:10:20 v/v/v). The mobile-phase flow rate was 1 mL min−1 with the injection volume of 20 μL and all the seven standard compounds were eluted within 14 min. The developed analytical method has been validated for the linearity, precision, sensitivity, accuracy, specificity, decision limit (CCα), and detection capability (CCβ). Experimental parameters influencing the extraction efficiency were evaluated and optimised. Under the optimum experimental conditions, good linearity over wide concentration ranges was obtained with the coefficient of determination R2 > 0.9989 for all the antibiotics. The limits of detection (LODs) and quantification (LOQs) ranged from 1.28 to 2.46 µg mL−1 and 3.87–7.46 µg mL−1, respectively. The relative standard deviations for the repeated analysis were below 8% indicating acceptable method precision. The accuracy study yielded satisfactory recoveries in the ranges 95.5–103% for the pure standard compounds and 83.8–112% for the spiked matrix-match milk samples. The results of the study revealed that the developed method is simple and fast and the SALLE method is appropriate for the simultaneous determination of targeted five multiclass antibiotic residues in the cow milk samples by LC-UV/Vis with a better efficiency.

Salting-out Assisted Liquid-Liquid Extraction for the rapid and simple simultaneous analysis of pyrrolizidine alkaloids and related N-oxides in honey and pollen

The application of salting out assisted liquid-liquid extraction for the rapid and simple simultaneous determination of pyrrolizidine alkaloids and related N-oxide in honey and pollen was evaluated. The determination of PAs and PANOs was obtained by ultra high performance liquid chromatography coupled with tandem mass spectrometry. The critical parameters (pH of the aqueous solution, extraction solvent, type and amount of salting-out agents) affecting SALLE performance were carefully studied and optimized using a chemometric approach. Under the optimal experimental conditions, the developed procedure showed excellent extraction efficiency (82–104 %) and recoveries (82–113 %) for all target analytes, except for Intermedine N-oxide, at three concentration levels (0.25, 2.5 and 25 μg kg−1 and 2.5, 25 and 250 μg kg-1 for honey and pollen samples, respectively), and satisfactory intra-day (<10) and inter-day (<13) precisions. The proposed method showed negligible matrix effect for both studied matrices and method quantification limits at very low levels (0.1−0.2 and 1−2 μg kg-1 for honey and pollen, respectively). The method was successfully applied to the analysis of honey (n = 71) and pollen (n = 6) samples. The 97 % and the 67 % of analyzed honey and pollen samples, respectively, turned out to be contaminated by at least one PA. Echimidine, echimidine N-oxide, intermedine and intermedine N-oxide significantly contributed to the contamination of the samples.

A simple and sensitive preconcentration strategy by coupling salting-out assisted liquid-liquid extraction with online three-step stacking for the determination of potent anti-tumour compound vinblastine and its precursor in biological samples by capillary electrophoresis

A sensitive capillary electrophoresis strategy was developed by combining salting-out assisted liquid–liquid extraction and online three-step stacking to detect trace quantities of antitumour indole alkaloids in complex biological samples. The proposed strategy fully exploits these two technologies such that extraction, online stacking and separation are combined in a fast and efficient manner. First, salting-out assisted liquid–liquid extraction was used to extract three indole alkaloids (vinblastine sulfate, catharanthine sulfate and vindoline) from complex biomasses. An appropriate volume of acetonitrile (ACN) was mixed with a faecal aqueous solution to precipitate proteins. The mixed solution was vortexed, followed by the addition of ammonium sulfate ((NH4)2SO4) to induce two-phase separation. Alkaloids were effectively extracted into the organic phase, which was then subjected to capillary electrophoresis (CE) analysis. The sensitivity of capillary electrophoresis was effectively improved by online three-step stacking. Good linearity of the calibration curve for each indole alkaloid was obtained in the concentration range of 0.1–1 μg/mL. Under optimal conditions, the sensitivity of ordinary injection was increased by up to 2366-fold, confirming the applicability of the proposed strategy for the sensitive determination of trace indole alkaloids in complex biological samples.

Advanced microextraction techniques for the analysis of amphetamines in human breast milk and their comparison with conventional methods

Breast milk analysis provides useful information about acute newborn exposure to harmful substances, such as psychoactive drugs abused by a nursing mother. Since breast milk represents a complex matrix with large amounts of interfering compounds, a comprehensive sample pre-treatment is necessary. This work focuses on determination of amphetamines and synthetic cathinones in human breast milk by microextraction techniques (liquid-phase microextraction and electromembrane extraction), and their comparison to more conventional treatment methods (protein precipitation, liquid-liquid extraction, and salting-out assisted liquid-liquid extraction). The aim of this work was to optimize and validate all the extraction procedures and thoroughly assess their advantages and disadvantages with special regard to their routine clinical use. The applicability of the extractions was further verified by the analysis of six real samples collected from breastfeeding mothers suspected of amphetamine abuse. The membrane microextraction techniques turned out to be the most advantageous as they required low amounts of organic solvents but still provided efficient sample clean-up, excellent quantification limit (0.5 ng mL-1), and good recovery (81–91% and 40–89% for electromembrane extraction and liquid-phase microextraction, respectively). The traditional liquid-liquid extraction as well as the salting-out assisted liquid-liquid extraction showed comparable recoveries (41–85% and 63–88%, respectively), but higher quantification limits (2.5 ng mL-1 and 5 ng mL-1, respectively). Moreover, these methods required multiple operating steps and were time consuming. Protein precipitation was fast and simple, but it demonstrated poor sample clean-up, low recovery (56–58%) and high quantification limit (5 ng mL-1). Based on the overall results, microextraction methods can be considered promising candidates, even for routine laboratory use.

Simultaneous LC-MS/MS bioanalysis of alkaloids, terpenoids, and flavonoids in rat plasma through salting-out-assisted liquid-liquid extraction after oral administration of extract from Tetradium ruticarpum and Glycyrrhiza uralensis: a sample preparation strategy to broaden analyte coverage of herbal medicines.

Herbal medicines have historically been practiced in combinatorial way, which achieves therapeutic efficacy by integrative effects of multi-components. Thus, the accurate and precise measurement of multi bioactive components in matrices is inalienable to understanding the metabolism and disposition of herbal medicines. In this study, aiming to provide a strategy that improves analyte coverage, evaluation of six protocols employing sample pretreatment methods- protein precipitation (PPT), liquid-liquid extraction (LLE), sugaring-out-assisted liquid-liquid extraction (SULLE), and salting-out-assisted liquid-liquid extraction (SALLE)- was performed by LC-MS/MS using rat plasma and a mixture of alkaloid (evodiamine, rutaecarpine, dehydroevodiamine), terpenoid (limonin, rutaevin, obacunone), and flavonoid (liquiritin, isoliquiritin, liquiritigenin) standards isolated from Tetradium ruticarpum and Glycyrrhiza uralensis. These protocols were as follows: (1) PPT with methanol, (2) PPT with acetonitrile, (3) LLE with methyl tertiary-butyl ether-dichloromethane, (4) LLE with ethyl acetate-n-butanol, (5) SALLE with ammonium acetate, (6) SULLE with glucose. The results suggested that SALLE produced broader analyte coverage with satisfactory reproducibility, acceptable recovery, and low matrix interference. Then, sample preparation procedure of SALLE, chromatographic conditions, and mass spectrometric parameters were optimized, followed by method validation, showing that good sensitivity (LLOQ ≤1 ng mL-1), linearity (r ≥0.9933),precision (RSD≤ 14.45%), accuracy (89.54~110.87%), and stability could be achieved. Next, the developed method was applied successfully to determine the pharmacokinetic behavior of the nine compounds in rat plasma after intragastric administration with an extract from Tetradium ruticarpum and Glycyrrhiza uralensis (Wuzhuyu-Gancao pair). Based on an extensive review and experiments, a sample preparation procedure that matches with LC-MS/MS technique and can get wider analyte coverage was outlined. The developed SALLE method is rapid, reliable, and suitable for bioanalysis of analytes with diverse polarity, which was expected to be a promising strategy for the pharmacokinetic studies of herbal medicines. Graphical abstract.

Exploring miniaturized sample preparation approaches combined with LC-QToF-MS for the analysis of sulfonamide antibiotic residues in meat- and/or egg-based baby foods

Miniaturized and simplified sample preparation methods with reduced consumption of chemicals and non-halogenated solvents are presented for the determination of 12 sulfonamides in baby foods. Hydrophilic interaction liquid chromatography coupled to quadrupole time-of-flight mass spectrometry was used for the identification and quantification of the compounds based on the acquisition of full spectrum at high resolution with accurate mass for precursor and its fragment ions. Three miniaturized protocols based on QuEChERS, salting-out assisted liquid-liquid extraction or low-temperature cleanup were evaluated regarding the extraction efficiency and removal capability of matrix co-extractives. All approaches achieved satisfactory recoveries (70.0–120.0%); however, the miniaturized QuEChERS distinguished by lower co-extractives content in the final extract providing lower matrix effects. Thus, the performance characteristics of the miniaturized QuEChERS were established using different matrices: beef-, egg yolk- and vegetable-based baby food or chicken- and vegetable-based baby food, in compliance with the Codex Alimentarius Commission guidelines. The target compounds were investigated in 30 commercial baby foods.

Rapid and simultaneous determination of trigonelline, caffeine, and chlorogenic acid in green coffee bean extract.

A simple, inexpensive, and rapid method for simultaneous determination of trigonelline, caffeine, and chlorogenic acid from green coffee bean extract was proposed based on salting‐out assisted liquid–liquid extraction, using QuEChERS salt and acetonitrile followed by UV‐Vis analysis. The proposed method represents acceptable linearity for trigonelline (0.9978), caffeine (0.9995), and chlorogenic acid (0.9996) with excellent correlation (0.93 and 0.83) for trigonelline and caffeine, respectively, when compared to RP‐HPLC‐DAD. The proposed method could be used in coffee industries for quality control and geographical origin traceability studies of green coffee samples.

Simple and efficient method for the determination of fipronil and two main metabolites in eggs by capillary liquid chromatography

Capillary liquid chromatography (CLC) with UV-diode array detection has been proposed for the first time to determine fipronil and two metabolites, fipronil-sulfide and fipronil-sulfone in hen egg samples. Under optimum conditions, analytes eluted in less than 12 min. Despite the complexity of egg samples, a simple and fast sample preparation method based on salting-out assisted liquid–liquid extraction (SALLE) was developed using acetonitrile as extraction solvent and ammonium sulfate as salting out reagent. To obtain satisfactory extraction efficiencies for the target compounds, several parameters affecting the procedure were optimized, including the nature and amount of the extraction solvent and the type and amount of salting-out reagent, among others. Validation parameters of the proposed SALLE-CLC-UV method yielded satisfactory results with repeatability and intermediate precision, expressed as relative standard deviation (RSD), below 9% and 11%, respectively and recoveries above 80%. Good linearity was obtained (R2 > 0.990) with limits of detection (LOD) below 5 μg·kg−1. The advantages of a miniaturized technique such as CLC in terms of reduced sample and solvent consumption, combined with simplicity of the SALLE procedure, make this method an attractive green alternative to traditional LC for the monitoring of these residues in egg samples.