Salting-out Assisted Liquid-liquid Extraction Research Articles

Evaluation of the Suitability of Analytical Methods in Trichothecene A and B Degradation

An investigation was conducted to standardize conditions for laccase and lipase activity required to maximize trichothecene degradation. The analytical methods were suitable and validated in model solutions for detection of five analytes (T-2 toxin, deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol), the methods were then applied in the degradation tests of these trichothecenes. The method of salting-out assisted liquid-liquid extraction (SALLE), using three different NaCl concentration levels, obtained recoveries in the range of 47.4-103.4% at pH 5.0 and 36.6-106.8% at pH 7.0, with an intra-day relative standard deviation under 15% for the majority of the compounds. Quantification limits remained in the region of 0.07 µg mL-1 for 15-acetyldeoxynivalenol and 0.3 µg mL-1 for nivalenol. Finally, the suitable analytical methods were applied in a study of trichothecene degradation by enzymatic action, resulting in a reduction of 12.3% for T-2 toxin, 68.4% for deoxynivalenol, 50.2% for 3-acetyldeoxynivalenol and 45.4% for 15-acetyldeoxynivalenol.

Salting-out assisted liquid-liquid extraction method coupled to gas chromatography for the simultaneous determination of thujones and pulegone in beverages

ABSTRACTA fast, simple and sensitive salting-out assisted liquid-liquid extraction method for the simultaneous determination of thujones and pulegone in beverage samples was developed. The extraction was achieved by adding ammonium sulphate to a miscible mixture of sample (10 mL) and acetonitrile (1.5 mL). The upper layer was directly injected into a capillary gas chromatography unit and detected using flame ionisation detector. The method was validated and calibration curve was linear with r2 > 0.99 over the range of 0.1–15 mg.kg–1 and 1–300 mg.kg−1 for thujone and pulegone, respectively. The limits of detection were 4.3 and 5.1 µg.kg–1 and the limit of quantification were 12.9 and 15.3 µg.kg–1 for thujone and pulegone, respectively. The relative standard deviation for inter- and intra -day precision was less than 10.1%. The proposed method was conveniently applied for the determination of these compounds in various herbal and fruit drinks, alcoholic beer and soft drinks. The average recoveries of the analyzed compounds ranged from 97 to 110% for thujone and from 87 to 119% for pulegone in three types of beverages. Thujones were not detected in all the 43 samples analysed while pulegone was detected in two samples (< quantitation limit and 1.78 mg.kg−1). Positive identification of the thujone and pulegone peaks were provided by GC-MS.

Comparison of salting-out and sugaring-out liquid–liquid extraction methods for the partition of 10-hydroxy-2-decenoic acid in royal jelly and their co-extracted protein content

Homogeneous liquid–liquid extraction (h-LLE) has been receiving considerable attention as a sample preparation method due to its simple and fast partition of compounds with a wide range of polarities. To better understand the differences between the two h-LLE extraction approaches, salting-out assisted liquid–liquid extraction (SALLE) and sugaring-out assisted liquid–liquid extraction (SULLE), have been compared for the partition of 10-hydroxy-2-decenoic acid (10-HDA) from royal jelly, and for the co-extraction of proteins. Effects of the amount of phase partition agents and the concentration of acetonitrile (ACN) on the h-LLE were discussed. Results showed that partition efficiency of 10-HDA depends on the phase ratio in both SALLE and SULLE. Though the partition triggered by NaCl and glucose is less efficient than MgSO4 in the 50% (v/v) ACN-water mixture, their extraction yields can be improved to be similar with that in MgSO4 SALLE by increasing the initial concentration of ACN in the ACN-water mixture. The content of co-extracted protein was correlated with water concentration in the obtained upper phase. MgSO4 showed the largest protein co-extraction at the low concentration of salt. Glucose exhibited a large protein co-extraction in the high phase ratio condition. Furthermore, NaCl with high initial ACN concentration is recommended because it produced high extraction yield for 10-HDA and the lowest amount of co-extracted protein. These observations would be valuable for the sample preparation of royal jelly.

Salting-out assisted liquid-liquid extraction coupled with hydrophilic interaction chromatography for the determination of biguanides in biological and environmental samples

A new salting-out assisted liquid-liquid extraction (SALLE) sample preparation method for the determination of the polar anti-diabetic biguanide drugs (metformin, buformin and phenformin) in blood plasma, urine and lake water samples were developed. The SALLE was performed by mixing samples (plasma (0.2mL), urine or lake water (1.0mL)) with acetonitrile (0.4mL for plasma, 0.5mL for urine or lake water), sodium hydroxide powder was then added for the phase separation. The effects of type of salting-out reagent, type of extraction solvent, volumes of acetonitrile and sample, amount of sodium hydroxide, vortexing and centrifugation times on the extraction efficiency were investigated. The upper layer, containing the biguanides, was directly injected into a HPLC unit using ZIC-HILIC column (150mm×2.1mm×3.5μm) and was detected at 236nm. The method was validated and calibration curves were linear with r2>0.99 over the range of 20–2000μgL−1 for plasma and 5–2000μgL−1 for urine and lake water samples. The limits of detection were in the range (3.8–5.6)μgL−1, (0.8–1.5)μgL−1 and (0.3–0.8)μgL−1 for plasma, urine and lake water, respectively. The accuracies in the three matrices were within 87.3–103%, 87.4–109%, 82.2–109% of the nominal concentration for metformin, buformin and phenformin, respectively. The relative standard deviation for inter- and intra −day precision were in the range of 1.0–17% for all analytes in the three matrices.

A high-throughput UHPLC method for the analysis of 5-nitroimidazole residues in milk based on salting-out assisted liquid-liquid extraction.

A novel salting-out assisted liquid-liquid extraction (SALLE) method has been developed for the extraction of eight 5-NDZ antibiotics from milk samples prior to their analysis by UHPLC. An exhaustive study of the parameters involved in the SALLE procedure has been carried out, optimizing the extraction solvent volume, the amount of the salt agent, and the centrifugation and vortex timing by an experimental design. After sample treatment, the obtained extract was reconstituted in the mobile phase (6:94 (v/v) acetonitrile/water containing 0.1% (v/v) of formic acid) and analyzed by the proposed UHPLC-UV method. Separation was accomplished in a C18 Zorbax Eclipse Plus (50mm×2.1mm, 1.8μm) column at 45°C within 8min. Gradient mode was considered using a mobile phase consisting of 0.1% (v/v) formic acid aqueous solution and acetonitrile containing 0.1% (v/v) formic acid at a flow rate of 0.45mL/min. Analytical signals were monitored at 320nm. Matrix-matched calibration curves showed satisfactory linearity (R2≥0.996). LODs, ranging from 2 to 4μg/L, were achieved and precision studies showed RSDs lower than 12.8% in terms of peak height. Additionally, recoveries higher than 62.8% were obtained for all studied compounds in milk samples.

Liquid chromatography-tandem mass spectrometric assay for the quantitative determination of the tyrosine kinase inhibitor quizartinib in mouse plasma using salting-out liquid-liquid extraction.

A bioanalytical assay for quizartinib -a potent, and selective FLT3 tyrosine kinase inhibitor- in mouse plasma was developed and validated. Salting-out assisted liquid-liquid extraction (SALLE), using acetonitrile and magnesium sulfate, was selected as sample pretreatment with deuterated quizartinib as internal standard. Separation was performed with reversed-phase liquid chromatography followed by detection with positive electrospray-triple quadrupole mass spectrometry in the selected reaction monitoring mode. The assay was successfully validated for mouse plasma in a 2-2000ng/ml calibration range with r2=0.9958±0.0028 (n=7) for linear regression with the inverse square of the concentration as a weighting factor. The within-run precision (n=18), between-run precision and accuracy were 2.9-6.0%, 4.5-8.9% and 91.7-109.4% respectively. The drug was stable under all relevant conditions. Finally, the assay was successfully applied in a pharmacokinetic pilot study in plasma of FVB/NRj mice treated with quizartinb orally.

Glyoxal and methylglyoxal as urinary markers of diabetes. Determination using a dispersive liquid–liquid microextraction procedure combined with gas chromatography–mass spectrometry

Glyoxal (GO) and methylglyoxal (MGO) are α-oxoaldehydes that can be used as urinary diabetes markers. In this study, their levels were measured using a sample preparation procedure based on salting-out assisted liquid–liquid extraction (SALLE) and dispersive liquid–liquid microextraction (DLLME) combined with gas chromatography-mass spectrometry (GC–MS). The effect of the derivatization reaction with 2,3-diaminonaphthalene, the addition of acetonitrile and sodium chloride to urine, and the DLLME step using the acetonitrile extract as dispersant solvent and carbon tetrachloride as extractant solvent were carefully optimized. Quantification was performed by the internal standard method, using 5-bromo-2-chloroanisole. The intraday and interday precisions were lower than 6%. Limits of detection were 0.12 and 0.06ngmL−1, and enrichment factors 140 and 130 for GO and MGO, respectively. The concentrations of these α-oxoaldehydes in urine were between 0.9 and 35.8ngg−1 levels (creatinine adjusted). A statistical comparison of the analyte contents of urine samples from non-diabetic and diabetic patients pointed to significant differences (P=0.046, 24 subjects investigated), particularly regarding MGO, which was higher in diabetic patients. The novelty of this study compared with previous procedures lies in the treatment of the urine sample by SALLE based on the addition of acetonitrile and sodium chloride to the urine. The DLLME procedure is performed with a sedimented drop of the extractant solvent, without a surfactant reagent, and using acetonitrile as dispersant solvent. Separation of the analytes was performed using GC–MS detection, being the analytes unequivocal identified. The proposed procedure is the first microextraction method applied to the analysis of urine samples from diabetic and non-diabetic patients that allows a clear differentiation between both groups using a simple analysis.

Salting-out assisted liquid–liquid extraction combined with gas chromatography-mass spectrometry for the determination of pyrethroid insecticides in high salinity and biological samples

A salting-out assisted liquid–liquid extraction (SALLE) combined with gas chromatography-mass spectrometry (GC–MS) method was developed for the determination of four pyrethroid insecticides (PYRs) in high salinity and biological samples. Several parameters including sample pH, salting-out solution volume and salting-out solution pH influencing the extraction efficiency were systematically investigated with the aid of orthogonal design. The optimal extraction conditions of SALLE were: 4mL of salting-out solution with pH=4 and the sample pH=3. Under the optimum extraction and determination conditions, good responses for four PYRs were obtained in a range of 5–5000ng/mL, with linear coefficients greater than 0.998. The recoveries of the four PYRs ranged from 74% to 110%, with standard deviations ranging from 1.8% to 9.8%. The limits of detection based on a signal-to-noise ratio of 3 were between 1.5–60.6ng/mL. The method was applied to the determination of PYRs in urine, seawater and wastewater samples with a satisfactory result. The results demonstrated that this SALLE-GC–MS method was successfully applied to determine PYRs in high salinity and biological samples. SALLE avoided the need for the elimination of salinity and protein in the sample matrix, as well as clean-up of the extractant. Most of all, no centrifugation or any special apparatus are required, make this a promising method for rapid sample preparation procedure.

A simple LC–MS/MS method facilitated by salting‐out assisted liquid–liquid extraction to simultaneously determine trans‐resveratrol and its glucuronide and sulfate conjugates in rat plasma and its application to pharmacokinetic assay

A simple LC-MS/MS method facilitated by salting-out assisted liquid-liquid extraction (SALLE) was applied to simultaneously investigate the pharmacokinetics of trans-resveratrol (Res) and its major glucuronide and sulfate conjugates in rat plasma. Acetonitrile-methanol (80:20, v/v) and ammonium acetate (10 mol L-1 ) were used as extractant and salting-out reagent to locate the target analytes in the supernatant after the aqueous and organic phase stratification, then the analytes were determined via gradient elution by LC-MS/MS in negative mode in a single run. The analytical method was validated with good selectivity, acceptable accuracy (>85%) and low variation of precision (<15%). SALLE showed better extraction efficiency of target glucuronide and sulfate conjugates (>80%). The method was successfully applied to determine Res and its four conjugated metabolites in rat after Res administration (intragastric, 50 mg kg-1 ; intravenous, 10 mg kg-1 ). The systemic exposures to Res conjugates were much higher than those to Res (AUC0-t , i.v., 7.43 μm h; p.o., 8.31 μm h); Res-3-O-β-d-glucuronide was the major metabolite (AUC0-t , i.v., 66.1 μm h; p.o., 333.4 μm h). The bioavailability of Res was estimated to be ~22.4%. The reproducible SALLE method simplified the sample preparation, drastically improved the accuracy of the concomitant assay and gave full consideration of extraction recovery to each target analyte in bio-samples.

Comparison of green sample preparation techniques in the analysis of pyrethrins and pyrethroids in baby food by liquid chromatography–tandem mass spectrometry

A new selective and sensitive liquid chromatography triple quadrupole mass spectrometry method was developed for simultaneous analysis of natural pyrethrins and synthetic pyrethroids residues in baby food. In this study, two sample preparation methods based on ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) and salting-out assisted liquid–liquid extraction (SALLE) were optimized, and then, compared regarding the performance criteria. Appropriate linearity in solvent and matrix-based calibrations, and suitable recoveries (75–120%) and precision (RSD values≤16%) were achieved for selected analytes by any of the sample preparation procedures. Both methods provided the analytical selectivity required for the monitoring of the insecticides in fruit-, cereal- and milk-based baby foods. SALLE, recognized by cost-effectiveness, and simple and fast execution, provided a lower enrichment factor, consequently, higher limits of quantification (LOQs) were obtained. Some of them too high to meet the strict legislation regarding baby food. Nonetheless, the combination of ultrasound and DLLME also resulted in a high sample throughput and environmental-friendly method, whose LOQs were lower than the default maximum residue limit (MRL) of 10μgkg−1 set by European Community for baby foods. In the commercial baby foods analyzed, cyhalothrin and etofenprox were detected in different samples, demonstrating the suitability of proposed method for baby food control.

One step salting-out assisted liquid-liquid extraction followed by UHPLC-ESI-MS/MS for the analysis of isoflavones in soy milk.

We developed and validated a fast UHPLC-ESI-MS/MS in combination with one step salting-out assisted liquid-liquid extraction (SALLE) for high throughput analysis of 12 isoflavones in soy milks. Conventional sample preparation requires two steps composing time-consuming freeze-drying (72h) and solvent extraction (2h). The SALLE required only about 40min, which was over 100times faster without compromising the extraction efficiency. The baseline separation of 12 isoflavones was achieved in 2.5min by the UHPLC-MS/MS which is the fastest chromatographic method ever reported. The new method was fast, simple, selective, sensitive, precise and accurate. The method was successfully applied to 22 commercial soy milks for the high throughput analysis of isoflavones. The new method would be a fast, simple, reliable, and useful measure for the analysis of isoflavones in soy milk especially in the laboratories facing the challenges of saving the analytical time, labor cost and solvent usage.

Validation of a new method based on salting-out assisted liquid-liquid extraction and UHPLC-MS/MS for the determination of betalactam antibiotics in infant dairy products

In this work a new multiresidue method has been developed for the determination of 15 betalactam antibiotics in infant milk and yogurt based on follow-on milk by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The separation was achieved in 6min, using a Kinetex Biphenyl Core-Shell column (50mmx2.1mm, 1.7µm), with a mobile phase of water with 0.05% acetic acid and methanol. The analytes were detected in ESI+ with multiple reaction monitoring mode and fragmentation conditions were optimized to obtain the highest sensitivity. The use of a biphenyl bonded column allowed to obtain a satisfactory selectivity for all the studied analytes. Moreover, ion-pair salting-out assisted liquid-liquid extraction (IP-SALLE) has been proposed as sample treatment and optimized by means of experimental design. Under optimum conditions, the recoveries for fortified samples ranged from 79% to 93%, (RSD <7.5%). The limits of quantification were lower than 9.0µgkg−1, showing the high sensitivity and applicability of this fast and simple method. The results in terms of analysis time, sensitivity and accuracy showed the suitability of this procedure for the monitoring of betalactam residues in different infant foods.

An Insight on Salting-out Assisted Liquid-Liquid Extraction for Phytoanalysis.

Salting-out assisted liquid-liquid extraction (SALLE) is a technique that, although simple and not requiring any complex equipment, is very powerful and versatile. It has obtained growing interest in bioanalysis particularly when combined with chromatographic techniques. Herein, fennel seeds (Foeniculum vulgare Mill.) were used as a case-study to show the application of SALLE in phytochemical analysis. SALLE combined with HPLC-UV-MS/MS and GC-MS. By HPLC-UV-MS/MS analysis of the organic extract it was possible to identify various phenolic compounds, including quercetin derivatives, caffeic acid, p-coumaric acid and chlorogenic acid. The main compounds identified by GC-MS were estragole, fenchone, anisaldehyde, anethole, benzaldehyde, camphor and apiole. HPLC and GC analysis of the extracts showed that it is possible to isolate, in only one step, a wide range of compounds with distinct properties, allowing a detailed phytochemical analysis. Copyright © 2017 John Wiley & Sons, Ltd.

Salting-out Assisted Liquid-Liquid Extraction for the Determination of Multiresidue Pesticides in Alcoholic Beverages by High Performance Liquid Chromatography

A salting-out assisted liquid-liquid extraction (SALLE) method followed by high-performance liquid chromatography with ultraviolet-visible detector (HPLC-UV/Vis) has been proposed for determination of five multiclass pesticides residues including, atrazine, ametryn, terbutryn, carbaryl and chlorothalonil from various alcoholic beverages: beer, wine and Ethiopian honey wine (<i>Tej</i>). Experimental parameters influencing the extraction efficiency of the method such as the type and concentration of salt, volume of acetonitrile (the extraction solvent) and pH of the sample were assayed and the optimum conditions were established. Under the optimum experimental conditions, matrix-matched calibration curves were constructed using beer sample as the representative matrix and good linearity over wide concentration ranges were obtained with coefficient of determination (r²) of 0.997 or better. The limits of detection (LOD) and quantification (LOQ) of the method, which were determined as 3 and 10 times a signal-to-noise ratio (S/N), were in the ranges of 1.3-3.9 and 4.5–12.8 μg L^-1, respectively. Precisions studied in terms of repeatability and intermediate precision (with-in lab reproducibility) at two concentration levels have demonstrated acceptable %RSD values, which were less than 10% in both cases. The applicability of the method was also investigated by analyzing various alcoholic beverages and demonstrated satisfactory recoveries in the ranges of 71-104% with their corresponding %RSDs less than 10% in all cases. The results of the study revealed that the developed SALLE method is selective and efficient sample preparation procedure prior to quantitative analysis of the target analytes by HPLC-UV/Vis.

Salting-Out Assisted Liquid-Liquid Extraction Combined with HPLC for Quantitative Extraction of Trace Multiclass Pesticide Residues from Environmental Waters

In this study, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of carbaryl, atrazine, propazine, chlorothalonil, dimethametryn and terbutryn in environmental water samples. Parameters affecting the extraction efficiency such as type and volume of extraction solvent, sample volume, salt type and amount, centrifugation speed and time, and sample pH were optimized. Under the optimum extraction conditions the method was linear over the range of 10 - 100 μg/L (carbaryl), 8 - 100 μg/L (atarzine), 7 - 100 μg/L (propazine) and 9 - 100 μg/L (chlorothalonil, terbutryn and dimethametryn) with correlation coefficients (R2) between 0.99 and 0.999. Limits of detection and quantification ranged from 2.0 to 2.8 μg/L and 6.7 to 9.5 μg/L, respectively. The extraction recoveries obtained for ground, lake and river waters were in a range of 75.5% to 106.6%, with the intra-day and inter-day relative standard deviation lower than 3.4% for all the target analytes. All of the target analytes were not detected in these samples. Therefore, the proposed SALLE-HPLC-DAD method is simple, rapid, cheap and environmentally friendly for the determination of the aforementioned herbicides, insecticide and fungicide residues in environmental water samples.

Simultaneous Screening and Quantification of Basic, Neutral and Acidic Drugs in Blood Using UPLC-QTOF-MS

An analytical method using ultra performance liquid chromatography (UPLC) quadrupole time-of-flight mass spectrometry (QTOF-MS) was developed and validated for the targeted toxicological screening and quantification of commonly used pharmaceuticals and drugs of abuse in postmortem blood using 100 µL sample. It screens for more than 185 drugs and metabolites and quantifies more than 90 drugs. The selected compounds include classes of pharmaceuticals and drugs of abuse such as: antidepressants, antipsychotics, analgesics (including narcotic analgesics), anti-inflammatory drugs, benzodiazepines, beta-blockers, amphetamines, new psychoactive substances (NPS), cocaine and metabolites. Compounds were extracted into acetonitrile using a salting-out assisted liquid-liquid extraction (SALLE) procedure. The extracts were analyzed using a Waters ACQUITY UPLC coupled with a XEVO QTOF mass spectrometer. Separation of the analytes was achieved by gradient elution using Waters ACQUITY HSS C18 column (2.1 mm x 150 mm, 1.8 μm). The mass spectrometer was operated in both positive and negative electrospray ionization modes. The high-resolution mass spectrometry (HRMS) data was acquired using a patented Waters MSE acquisition mode which collected low and high energy spectra alternatively during the same acquisition. Positive identification of target analytes was based on accurate mass measurements of the molecular ion, product ion, peak area ratio and retention times. Calibration curves were linear over the concentration range 0.05-2 mg/L for basic and neutral analytes and 0.1-6 mg/L for acidic analytes with the correlation coefficients (r2)>0.96 for most analytes. The limits of detection (LOD) were between 0.001-0.05 mg/L for all analytes. Good recoveries were achieved ranging from 80% to 100% for most analytes using the SALLE method. The method was validated for sensitivity, selectivity, accuracy, precision, stability, carryover and matrix effects. The developed method was tested on a number of authentic forensic samples producing consistent results that correlated with results obtained from other validated methods.

Development of a multi-matrix LC–MS/MS method for urea quantitation and its application in human respiratory disease studies

In human respiratory disease studies, liquid samples such as nasal secretion (NS), lung epithelial lining fluid (ELF), or upper airway mucosal lining fluid (MLF) are frequently collected, but their volumes often remain unknown. The lack of volume information makes it hard to estimate the actual concentration of recovered active pharmaceutical ingredient or biomarkers. Urea has been proposed to serve as a sample volume marker because it can freely diffuse through most body compartments and is less affected by disease states. Here, we report an easy and reliable LC–MS/MS method for cross-matrix measurement of urea in serum, plasma, universal transfer medium (UTM), synthetic absorptive matrix elution buffer 1 (SAMe1) and synthetic absorptive matrix elution buffer 2 (SAMe2) which are commonly sampled in human respiratory disease studies. The method uses two stable-isotope-labeled urea isotopologues, [15N2]-urea and [13C,15N2]-urea, as the surrogate analyte and the internal standard, respectively. This approach provides the best measurement consistency across different matrices. The analyte extraction was individually optimized in each matrix. Specifically in UTM, SAMe1 and SAMe2, the unique salting-out assisted liquid-liquid extraction (SALLE) not only dramatically reduces the matrix interferences but also improves the assay recovery. The use of an HILIC column largely increases the analyte retention. The typical run time is 3.6min which allows for high throughput analysis.

Salting-out assisted liquid-liquid extraction coupled to ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of tetracycline residues in infant foods.

The use of salting-out assisted liquid-liquid extraction (SALLE) combined with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) has been evaluated for the determination of tetracyclines in infant foods based on meat and vegetables or in milk. To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized. Analytical performances of the method were satisfactory, obtaining limits of quantification lower than 0.48μgkg-1 in all cases. The precision, expressed as relative standard deviation (%, RSD) was below 11.3%. The extraction efficiency for fortified samples ranged from 89.2 to 96.8%, with RSDs lower than 7.3%. Matrix effect was evaluated for all samples studied, being lower than |21|% in all cases. In relation to the low solvent consumption, the proposed methodology could be considered rapid, cheap and environmentally friendly. Its applicability has been successfully tested in a wide range of infant foods.

Salting-out assisted liquid-liquid extraction and partial least squares regression to assay low molecular weight polycyclic aromatic hydrocarbons leached from soils and sediments

A novel method was developed to determine low molecular weight polycyclic aromatic hydrocarbons in aqueous leachates from soils and sediments using a salting-out assisted liquid-liquid extraction, synchronous fluorescence spectrometry and a multivariate calibration technique. Several experimental parameters were controlled and the optimum conditions were: sodium carbonate as the salting-out agent at concentration of 2molL−1, 3mL of acetonitrile as extraction solvent, 6mL of aqueous leachate, vortexing for 5min and centrifuging at 4000rpm for 5min. The partial least squares calibration was optimized to the lowest values of root mean squared error and five latent variables were chosen for each of the targeted compounds. The regression coefficients for the true versus predicted concentrations were higher than 0.99. Figures of merit for the multivariate method were calculated, namely sensitivity, multivariate detection limit and multivariate quantification limit. The selectivity was also evaluated and other polycyclic aromatic hydrocarbons did not interfere in the analysis. Likewise, high performance liquid chromatography was used as a comparative methodology, and the regression analysis between the methods showed no statistical difference (t-test). The proposed methodology was applied to soils and sediments of a Brazilian river and the recoveries ranged from 74.3% to 105.8%. Overall, the proposed methodology was suitable for the targeted compounds, showing that the extraction method can be applied to spectrofluorometric analysis and that the multivariate calibration is also suitable for these compounds in leachates from real samples.

Liquid chromatography-tandem mass spectrometric assay for the T790M mutant EGFR inhibitor osimertinib (AZD9291) in human plasma.

A method for the quantitative analysis by ultra-performance liquid chromatography-tandem mass spectrometry of the highly selective irreversible covalent inhibitor of EGFR-TK, osimertinib in human plasma was developed and validated, using pazopanib as an internal standard. The validation was performed in a range from 1 to 1000ng/ml, with the lowest level corresponding to the lower limit of quantitation. Gradient elution was performed on a 1.8μm particle trifunctional bonded C18 column by 1% (v/v) formic acid in water, and acetonitrile as mobile phase. The analyte was detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer after positive ionization with the heated electrospray interface. Within-day precisions ranged from 3.4 to 10.3%, and between-day precisions from 3.8 to 10.4%, accuracies were 95.5-102.8%. Plasma (either lithium heparin or sodium EDTA) pretreatment was performed by salting-out assisted liquid-liquid extraction using acetonitrile and magnesium sulfate. This method was used to analyze the osimertinib blood plasma levels of five adult patients with metastatic T790M mutated non-small cellular lung carcinoma for therapeutic drug monitoring purposes.