Rapid determination of residual pesticides in tobacco by the quick,easy, cheap,effective, rugged,and safe sample pretreatment method coupled with LC–MS

A quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample pretreatment method coupled with LC–MS was developed for the determination of 11 pesticides in tobacco. Sample pretreatment parameters and instrumental parameters of LC–MS were investigated, and the optimal conditions were selected. Under the optimized conditions, the 11 pesticides were detected simultaneously with a good linear relationship (r² = 0.9993–0.9999) and high precisions (less than 5% of the RSD of peak areas). The LODs were in the range of 0.1–5.0 μg/L. Compared with SPE clean‐up, QuEChERS greatly simplified the sample pretreatment with simple solvent extraction system. After QuEChERS pretreatment, no serious matrix effects were observed. Used for the analysis of real samples, metalaxyl was found in cigarette and tobacco samples at 63.47 and 132.27 ng/g, respectively. The recoveries for 11 pesticides were in the range of 70.03–118.69%, and RSDs were less than 10%. The proposed method is simple, low cost, and has good reproducibility.     

Determination of synephrine in feeds by a novel quick,easy, cheap,effective, rugged,and safe solid‐phase extraction method combined with UHPLC–MS/MS

To detect and quantify synephrine in feed, an effective analytical method based on quick, easy, cheap, effective, rugged, and safe solid‐phase extraction coupled to ultra high performance liquid chromatography with tandem mass spectrometry was developed with isotopic internal standards. Pretreatment was performed using quick, easy, cheap, effective, rugged, and safe solid‐phase extraction with primary secondary amine and C18 sorbent as sorbents in combination with Oasis MCX column clean‐up to extract and purify feed samples. Tandem mass spectrometry detection in positive ion mode was conducted in positive multiple reaction monitoring mode in addition to the quantitative internal standard method. Two transitions of synephrine at m/z 168.1/150.0 and 168.1/135.0 were selected, and m/z 168.1/135.0 was determined as the quantification ion pair. D₉‐Terbutaline was selected as an internal standard, for which m/z 235.1/153.0 was selected as the quantification ion pair. Good linearity was shown for synephrine in the range of 0.5–50 μg/L, and the correlation coefficient exceeded 0.999. The recoveries in three different feed samples at three spiked levels were 81.42–112.08%, and the relative standard deviations were not greater than 14.66%. The method proposed in this study was reliable and highly effective, and its sensitivity, accuracy, and precision are suitable for determining synephrine residues in feed samples.     

Determination of polycyclic aromatic hydrocarbon metabolites in milk by a quick,easy, cheap,effective, rugged and safe extraction and capillary electrophoresis

We describe the first application of a quick, easy, cheap, effective, rugged and safe extraction technique to the CZE analysis of monohydroxylated metabolites of polycyclic aromatic hydrocarbons in milk. Complete resolution of 2‐hydroxyfluorenene, 1‐hydroxynaphthalene, 2‐hydroxynaphthalene, 3‐hydroxyphenanthrene, and 9‐hydroxyphenanthrene was accomplished in 4 min of electrophoretic run. Limits of detection at the parts‐per‐billion were obtained with a single solvent (acetonitrile) for metabolite extraction and sample stacking. The small sample volume (1.2 mL) and the conservative usage of chemicals provided a simple and rapid procedure for the simultaneous extraction of numerous samples. Adding 4 min of electrophoretic run per sample, it should be possible to screen ten samples in approximately 1 h of analysis time. The nanoliter extract volume required for sample injection allows for further chromatographic usage and confirmation of positive samples. The unique electrophoretic pattern of the studied metabolites demonstrates the potential for the unambiguous determination of positional isomers with very similar chromatographic behaviors and undistinguishable mass fragmentation patterns.     

Multiresidue analysis of glucocorticoids in milk by LC–MS/MS with low‐temperature purification and dispersive solid‐phase extraction

A multiresidue method for the determination of 12 glucocorticoids (clobetasol propionate, budesonide, triamcinolone, triamcinolone acetonide, fludrocortisone acetate, flumethasone, beclomethasone, prednisone acetate, 6‐α‐methylprednisolone, hydrocortisone, cortisone, and prednisone) in bovine milk was developed using liquid chromatography with tandem mass spectrometry. Isoflupredone was used as an internal standard. Milk samples were treated with ethyl acetate to extract glucocorticoids and were frozen at −20°C for 6 h to precipitate fat. The extract was dried under nitrogen, and residues were dissolved in an acetonitrile/water solution. A further clean‐up step was used by dispersive solid‐phase extraction, with octadecyl silica and primary secondary amine as the absorbents. The recoveries of glucocorticoids spiked at 0.5, 1.0, 10.0 μg/kg ranged from 75.7 to 117.3%, except for clobetasol propionate and budesonide (16.1–49.5%). The limits of quantification were 0.01–0.5 μg/kg in milk. This method has been successfully applied in real samples. The results demonstrated that this method is simple, robust, and suitable for identification of glucocorticoid residues in milk.     

Analysis of polycyclic aromatic hydrocarbons in fish: evaluation of a quick,easy, cheap,effective, rugged,and safe extraction method

QuEChERS method was evaluated for extraction of 16 PAHs from fish samples. For a selective measurement of the compounds, extracts were analysed by LC with fluorescence detection. The overall analytical procedure was validated by systematic recovery experiments at three levels and by using the standard reference material SRM 2977 (mussel tissue). The targeted contaminants, except naphthalene and acenaphthene, were successfully extracted from SRM 2977 with recoveries ranging from 63.5–110.0% with variation coefficients not exceeding 8%. The optimum QuEChERS conditions were the following: 5 g of homogenised fish sample, 10 mL of ACN, agitation performed by vortex during 3 min. Quantification limits ranging from 0.12–1.90 ng/g wet weight (0.30–4.70 μg/L) were obtained. The optimized methodology was applied to assess the safety concerning PAHs contents of horse mackerel (Trachurus trachurus), chub mackerel (Scomber japonicus), sardine (Sardina pilchardus) and farmed seabass (Dicentrarchus labrax). Although benzo(a)pyrene, the marker used for evaluating the carcinogenic risk of PAHs in food, was not detected in the analysed samples (89 individuals corresponding to 27 homogenized samples), the overall mean concentration ranged from 2.52 ± 1.20 ng/g in horse mackerel to 14.6 ± 2.8 ng/g in farmed seabass. Significant differences were found between the mean PAHs concentrations of the four groups.     

Determination of trihalomethanes in soil matrices by simplified quick,easy, cheap,effective, rugged and safe extraction and fast gas chromatography with electron capture detection

A method based on QuEChERS extraction is proposed for the determination of trihalomethanes (chloroform, bromodichloromethane, dibromocloromethane and bromoform) in soil samples. The new version of QuEChERS adapted to soil samples consists of liquid extraction with ethyl acetate, the addition of water to moisten the samples, salting-out partitioning of the water with anhydrous MgSO₄, and direct injection of the organic extract, obtained after the centrifugation step, into the gas chromatograph. This simplified extraction procedure maintains the advantages of the original method and avoids some steps, making the final procedure simpler, faster, and cheaper, with the consequent reduction in errors associated with sample manipulation. The experimental conditions of the analytical method, based on fast gas chromatography (FGC) and micro-electron capture detection (μECD), were optimized. The column and oven program used allowed fast separation of the compounds in less than 4 min and the total analysis cycle time was as short as 10 min. The existence of a matrix effect was checked and the analytical conditions of the method were studied in a fortified garden soil sample. The highly sensitive and selective detector used afforded to detection limits in the order of ng/kg for the target compounds. To validate the proposed method two certified reference materials (CRMs) were analyzed.     

Determination of phthalate esters in soil using a quick,easy, cheap,effective, rugged,and safe method followed by GC–MS

A quick, easy, cheap, effective, rugged, and safe procedure was designed to extract pesticide residues from fruits and vegetables with a high percentage of water. It has not been used extensively for the extraction of phthalate esters from sediments, soils, and sludges. In this work, this procedure was combined with gas chromatography with mass spectrometry to determine 16 selected phthalate esters in soil. The extraction efficiency of the samples was improved by ultrasonic extraction and dissolution of the soil samples in ultra‐pure water, which promoted the dispersion of the samples. Furthermore, we have simplified the extraction step and reduced the risk of organic solvent contamination by minimizing the use of organic solvents. Different extraction solvents and clean‐up adsorbents were compared to optimize the procedure. Dichloromethane/n‐hexane (1:1, v/v) and n‐hexane/acetone (1:1, v/v) were selected as the extractants from the six extraction solvents tested. C18/primary secondary amine (1:1, m/m) was selected as the sorbent from the five clean‐up adsorbents tested. The recoveries from the spiked soils ranged from 70.00 to 117.90% with relative standard deviation values of 0.67–4.62%. The proposed approach was satisfactorily applied for the determination of phthalate esters in 12 contaminated soil samples.     

Fast ultrasound‐assisted extraction combined with LC–MS/MS of perfluorinated compounds in manure

A fast analytical method for the determination of perfluorinated compounds in poultry manure by LC–MS/MS was developed. The extraction was carried out by ultrasound‐assisted extraction of 1 g of sample, during 2 × 15 min using low volume (5.5 mL) of a mixture of methanol and acetonitrile. An efficient extraction of perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl sulfonamides from poultry manure was obtained with recoveries higher than 81%. The cleanup of extracts was carried out by dispersive SPE. The validation of the proposed method showed the suitability of this procedure to determine perfluorinated compounds in poultry manure with detection limits in the range of 0.44–2.12 ng/g, depending on the target compound. In comparison with previously published methods, the miniaturization of the sample preparation method with ultrasound‐assisted extraction together with the use of a core‐shell column permit a lower consumption of organic solvents and a fast analysis of perfluorinated compounds. Manure samples obtained from Spanish commercial farms were analyzed and low perfluorinated compounds levels were found, which may be originated by dietary or environmental exposure. The highest concentrations measured corresponded to the perfluoroalkyl sulfonates, which varied from 8.2 to 35.9 ng/g.     

Development and evaluation of microwave‐assisted and ultrasound‐assisted methods based on a quick,easy, cheap,effective, rugged,and safe sample preparation approach for the determination of bisphenol analogues in serum and sediments

Microwave‐ and ultrasound‐assisted methods based on a quick, easy, cheap, effective, rugged, and safe sample preparation approach followed by high‐performance liquid chromatography with tandem mass spectrometry were developed for the simultaneous determination of eight bisphenol analogues in serum and sediment. The developed methods provided satisfactory extraction efficiency for the energy provided by microwaves and ultrasound. Compositions of commercial sorbents (primary secondary amine, MgSO₄, octadecyl‐modified silica, and graphitized carbon black) were evaluated. The ultrasound‐assisted method was suited for serum using primary secondary amine, MgSO₄, and octadecyl‐modified silica as sorbents and a mixture of hexane and ethyl acetate as extraction solvent. The microwave‐assisted method worked better for sediment with tetrahydrofuran and methanol as solvents and primary secondary amine, MgSO₄, octadecyl‐modified silica, and graphitized carbon black as sorbents. Other experimental parameters, such as extraction temperature and time, were also optimized. The inter‐ and intraday relative standard deviations ranged from 2.7 to 5.5%. The limits of detection were between 0.1 and 1.0 ng/mL for serum and between 0.1 and 0.5 ng/g dry weight for sediment. The proposed methods were successfully applied to seven sediment and 20 human serum samples. The results showed that the developed methods were practical for the analysis and biomonitoring of bisphenols in sera and sediment.     

Determination of macrolide antibiotics residues in pork using molecularly imprinted dispersive solid‐phase extraction coupled with LC–MS/MS

A class‐specific macrolide molecularly imprinted polymer was synthesized by precipitation polymerization using tulathromycin as the template and methacrylic acid as the functional monomer. The polymers revealed different specific adsorption and imprinting factor for macrolides with different spatial arrangement of side chains as well as lactonic ring size. And the molecularly imprinted polymer possessed maximum adsorption capacity (54.1 mg/g) and highest imprinting factor (2.4) toward 15‐membered ring azithromycin. On the basis of molecularly imprinted polymer dispersive solid‐phase extraction, a rapid, selective, and reproducible method for simultaneous determination of seven macrolide antibiotics residues in pork was established by using liquid chromatography with tandem mass spectrometry. At spiking levels of 5, 10, 25, and 100 μg/kg, average recoveries of seven macrolides ranged from 68.6 to 95.5% with intraday and interday relative standard deviations below 8%. The limits of detection and limits of quantification were 0.2–0.5 and 0.5–2.0 μg/kg, respectively.     

Innovative mixture of salts in the quick,easy, cheap,effective, rugged,and safe method for the extraction of residual macrolides in milk followed by analysis with liquid chromatography and tandem mass spectrometry

A simple extraction technique has been developed for seven macrolide antibiotics in milk. The procedure involves a modified quick, easy, cheap, effective, rugged, and safe method based on acetonitrile extraction, followed by the addition of a mixture of salts (sodium sulfate, sodium chloride, and potassium carbonate) not yet reported in literature. The method was validated for tylosin and was selective, free of matrix effect, and linear in the range of 0.78–18.75 ng/mL in the final extract, corresponding to 0.125–3 times the maximum residue limit. The limit of detection, limit of quantification, decision limit, and detection capability were, respectively, 0.84, 2.79, 58.4, and 71.7 μg/kg. The overall average recovery at 25, 50, and 75 μg/kg ranged from 89–97%. Repeatability and intermediate precision expressed by relative standard deviations were below 10.5 and 12%, respectively. The extension of the validation for spiramycin, throleandomycin, oleandomycin, roxithromycin, erythromycin, and clarithromycin is under consideration since the procedure proved to be able to efficiently extract all studied macrolides, with recoveries from 74–104% at 50 μg/kg for tylosin, erythromycin, spiramycin, and oleandomycin and 20 μg/kg for throleandomycin, roxithromycin, and clarithromycin.     

Trace determination of five triazole fungicide residues in traditional Chinese medicine samples by dispersive solid‐phase extraction combined with ultrasound‐assisted dispersive liquid–liquid microextraction and UHPLC–MS/MS

A novel and reliable method for determination of five triazole fungicide residues (triadimenol, tebuconazole, diniconazole, flutriafol, and hexaconazol) in traditional Chinese medicine samples was developed using dispersive solid‐phase extraction combined with ultrasound‐assisted dispersive liquid–liquid microextraction before ultra‐high performance liquid chromatography with tandem mass spectrometry. The clean up of the extract was conducted using dispersive solid‐phase extraction by directly adding sorbents into the extraction solution, followed by shaking and centrifugation. After that, a mixture of 400 μL trichloromethane (extraction solvent) and 0.5 mL of the above supernatant was injected rapidly into water for the dispersive liquid–liquid microextraction procedure. The factors affecting the extraction efficiency were optimized. Under the optimum conditions, the calibration curves showed good linearity in the range of 2.0–400 (tebuconazole, diniconazole, and hexaconazole) and 4.0–800 ng/g (triadimenol and flutriafol) with the regression coefficients higher than 0.9958. The limit of detection and limit of quantification for the present method were 0.5–1.1 and 1.8–4.0 ng/g, respectively. The recoveries of the target analytes ranged from 80.2 to 103.2%. The proposed method has been successfully applied to the analysis of five triazole fungicides in traditional Chinese medicine samples, and satisfactory results were obtained.     

Simultaneous determination of pyrametostrobin and its two metabolites in cucumber and soil using a quick,easy, cheap,effective, rugged,and safe method with HPLC–MS/MS

An easy, effective and sensitive analytical method for the simultaneous determination of a novel fungicide pyrametostrobin and its two metabolites pyrametostrobin‐M1 and pyrametostrobin‐M2 in cucumber and soil was developed using a quick, easy, cheap, effective, rugged, and safe method with high‐performance liquid chromatography and tandem mass spectrometry. The extraction solvent was acetonitrile, and cleanup sorbents were primary secondary amine and graphitized carbon black for cucumber samples and primary secondary amine for soil samples. The three target compounds were successfully separated between 3.2 and 3.9 min using a Waters CORTECS™ C₁₈ column connected to an electrospray ionization source. All the matrix‐matched samples at three fortified levels (10, 100 and 1000  μg/kg) provided satisfactory recoveries in the range of 78.8–93.8% with relative standard deviations below 6.9%. The limits of quantitation for the three compounds were below 0.183 μg/kg. The proposed method was validated by analyzing real samples.     

Determination of hexabromocyclododecane enantiomers in chicken whole blood by a modified quick,easy, cheap,effective, rugged,and safe method with liquid chromatography and tandem mass spectrometry

A rapid and simple analytical method has been developed for the determination of hexabromocyclododecane enantiomers in chicken whole blood, based on a modified quick, easy, cheap, effective, rugged, and safe approach before liquid chromatography coupled with tandem mass spectrometry. The factors influencing performance of method were investigated by single factor experiment, and further optimized by the response surface methodology based on Box–Behnken design. The matrix effects were also evaluated by the isotopic dilution method. Under the optimal conditions, the proposed method showed good linearity within the range of 1–500 μg/L and good repeatability with relative standard deviation less than 9.5% (n = 5). The limits of detection (S/N = 3) were 0.03–0.19 μg/L. The developed method was successfully applied for the analysis of hexabromocyclododecane enantiomers in real chicken blood samples. The satisfactory recoveries ranging of 83.6–115.0% were obtained (at spiked levels of 5, 20, and 100 μg/L). The results demonstrated that the proposed method would be a practical value method for the determination of hexabromocyclododecane enantiomers in animal blood. It would be further developed with confidence to analyze other lipophilic organic pollutants in blood sample.     

Simultaneous determination of 106 pesticides in nuts by LC–MS/MS using freeze‐out combined with dispersive solid‐phase extraction purification

As a result of the low water content and high fat matrices in nuts, it is very difficult to simultaneously determine multi‐pesticides in trace levels. Here, a sample pretreatment method was developed in which, microwave‐assisted solvent extraction was firstly used to extract pesticides, and then a two‐step cleanup method was conducted combining freeze‐out with dispersive solid‐phase extraction to remove the lipidic matrix. By this way, 106 pesticides were simultaneously determined in the complicated nut sample by using an ultra‐high pressure liquid chromatography coupled with a tandem mass spectrometer. Average recoveries were 75.3–119.3% with relative standard deviations < 14% at three concentration levels. The limits of detection and quantification were in the ranges of 0.3–3.0 and 1.0–10.0 μg/kg, respectively. Furthermore, the method was successfully applied to the determination of pesticides in 180 commercial nut samples.     

Combination of a modified quick,easy, cheap,efficient, rugged,and safe extraction method with a deep eutectic solvent based microwave‐assisted dispersive liquid–liquid microextraction: Application in extraction and preconcentration of multiclass pesticide residues in tomato samples

In this study, a new two–step extraction procedure based on the combination of a modified quick, easy, cheap, effective, rugged, and safe extraction method with a deep eutectic solvent based microwave‐assisted dispersive liquid–liquid microextraction has been developed for the extraction of multiclass pesticides in tomato samples before their analysis by gas chromatography with flame ionization detection. In this method, initially, an aliquot of tomato is crushed and diluted with deionized water. The mixture is then passed through a filter paper and its residue and aqueous phase are separated. Afterwards, acetonitrile as an extraction/disperser solvent is passed through the filter paper containing the refuse. The analytes remained in the refuse are extracted into the acetonitrile and then the obtained extract is mixed with a deep eutectic solvent. The obtained mixture is injected into the tomato juice and placed in a microwave oven for 15 s. Consequently, a cloudy state is formed and the extractant containing the analytes are sedimented at the bottom of the tube after centrifugation. Finally, 1 μL of the sedimented phase is removed and injected into the separation system. Under the optimum conditions, limits of detection and quantification were in the ranges of 0.42–0.74 and 1.4–2.5 ng/g, respectively.     

Multiresidue method for the simultaneous determination of 16 acaricides by modified quick,easy, cheap,effective, rugged,and safe extraction and ultra‐high performance liquid chromatography coupled with tandem mass spectrometry in citrus

An ultra‐high performance liquid chromatography coupled with tandem mass spectrometry analytical method was developed for simultaneously determining 16 acaricides in citrus based on an optimized quick, easy, cheap, effective, rugged, safe strategy. Good linearities of the standard curve of 5–1000 μg/kg was obtained with regression coefficients higher than 0.9967. Recoveries for all compounds ranged from 72 to 111% with relative standard deviations lower than 14.4% at spiked levels of 5, 50, and 500 μg/kg. Low limits of detection and quantification were readily achieved ranging from 0.05 to 2.7 and 0.10 to 4.3 μg/kg, respectively. Matrix effects were also evaluated for 16 targets with most compounds achieved signal enhancement. Citrus peel gave the highest extent matrix effects, followed by whole citrus and pulp. Finally, this method was successfully applied to detect acaricides residues in real citrus samples. The results showed that pyridaben and quinalphos were the two most frequent and high‐concentration compounds with concentrations exceeding the maximum residue limits in five samples, suggesting that the use of these acaricides should be regulated in China in the future.     

Miniaturized matrix solid‐phase dispersion combined with ultrasound‐assisted dispersive liquid–liquid microextraction for the determination of three pyrethroids in soil

A simple and miniaturized pretreatment procedure combining matrix solid‐phase dispersion (MSPD) with ultrasound‐assisted dispersive liquid–liquid microextraction (UA‐DLLME) technique was proposed in first time for simultaneous determination of three pyrethroids (fenpropathrin, cyhalothrin and fenvalerate) in soils. The solid samples were directly extracted using MSPD procedure, and the eluent of MSPD was used as the dispersive solvent of the followed DLLME procedure for further purification and enrichment of the analytes before GC‐ECD analysis. Good linear relationships were obtained for all the analytes in a range of 5.0–500.0 ng/g with LOQs (S/N=10) ranged from 1.51 to 3.77 ng/g. Average recoveries at three spiked levels were in a range of 83.6–98.5% with RSD≤7.3%. The present method combined the advantages of MSPD and DLLME, and was successfully applied for the determination of three pyrethroids in soil samples.     

Qualitative-quantitative analysis of multi-mycotoxin in milk using the high-performance liquid chromatography-tandem mass spectrometry coupled with the quick,easy, cheap,effective, rugged and safe method

High-performance liquid chromatography-tandem mass spectrometry coupled with the quick, easy, cheap, effective, rugged and safe method was established for the qualitative and quantitative detections of 20 mycotoxins in milk. The linear range of this method was 0.01–10 μg/L and the correlation coefficients were all greater than or equal to 0.9933. At three levels of addition, the spiked recoveries ranged from 80.00 to 112.50%, relative standard deviations were 2.67–14.97%, limits of quantitation were 0.02–4.00 μg/kg, and limits of detection were 0.007–1.300 μg/kg. This developed procedure for the identification and quantitation of mycotoxins provided prospective support for quality regulation.     

Development of two fully automated quick,easy, cheap,effective, rugged,and safe pretreatment methods for the extraction of psychotropic drugs from whole blood samples

Quick, easy, cheap, effective, rugged, and safe extraction strategies are becoming increasingly adopted in various analytical fields to determine drugs in biological specimens. In the present study, we developed two fully automated quick, easy, cheap, effective, rugged, and safe extraction methods based on acetonitrile salting-out assisted liquid-liquid extraction (method 1) and acetonitrile salting-out assisted liquid-liquid extraction followed by dispersive solid-phase extraction (method 2) using a commercially available automated liquid-liquid extraction system. We applied these methods to the extraction of 14 psychotropic drugs (11 benzodiazepines and carbamazepine, quetiapine, and zolpidem) from whole blood samples. Both methods prior to liquid chromatography–tandem mass spectrometry analysis exhibited high linearity of calibration curves (correlation coefficients, > 0.9997), ppt level detection sensitivities, and satisfactory precisions (< 8.6% relative standard deviation), accuracies (within ± 16% relative error), and matrix effects (81–111%). Method 1 provided higher recovery rates (80–91%) than method 2 (72–86%), whereas method 2 provided higher detection sensitivities (limits of detection, 0.003–0.094 ng/mL) than method 1 (0.025–0.47 ng/mL) owing to the effectiveness of its dispersive solid-phase extraction cleanup step. These fully automated extraction methods realize reliable, labor-saving, user-friendly, and hygienic extraction of target analytes from whole blood samples.