Strategies for solid sample treatment

Critical Evaluation of Two Qualitative Analytical Approaches for Multiclass Determination of Veterinary Drugs in Bovine Muscle Using UHPLC-Q-Orbitrap: The Wind of Change in Brazilian Monitoring

Food safety is recognized as a main requirement for consumers, food industries, and official laboratories. Here, we present the optimization and screening qualitative validation of two multianalyte methods in bovine muscle tissues by ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry with an Orbitrap-type analyzer, operated with a heated ionization source in positive and negative mode. This aims for not only the simultaneous detection of veterinary drugs regulated in Brazil but also the prospection of antimicrobials not yet monitored. Two different sample preparation procedures were applied: method A-generic solid-liquid extraction with 0.1% formic acid (v/v) in an aqueous solution of EDTA 0.1% (w/v)-acetonitrile-methanol (1:1:1, v/v/v), followed by an additional ultrasound-assisted extraction and method B-QuEChERS. In both procedures, selectivity showed satisfactory conformity. From a detection capability (CCβ) equivalent to ½ the maximum residue limit, >34% of the analyte resulted in a false positive rate of <5%, preponderant by the QuEChERS method, which exhibited a higher yield of the sample. The results showed the potential application of both procedures in the routine analysis of foods by official laboratories, enabling the expansion of this methodological portfolio as well as its analytical scopes, thus optimizing the control of residues of veterinary drugs in the country.

Sample pretreatment and analytical methodology for the determination of antibiotics in swine wastewater and activated sludge

An analytical method for the simultaneous extraction and determination of eight veterinary antibiotics in swine wastewater and activated sludge was developed and validated based on the instrumental determination by liquid chromatography tandem quadrupole mass spectrometry. Ultrasound-assisted extraction and solid-phase extraction were introduced into the pretreatment procedure of the two complex environmental matrices. The critical steps involved in the sample pretreatment procedure and the instrumental analysis conditions were optimized progressively. Recoveries of the optimized method were good with 75.3-118.2% in wastewater and 82.8-130.1% in sludge. The absolute deviations of methods were lower than 11.7%, presenting a high reproducibility and precision. The limits of quantification for the eight pharmaceuticals in wastewater and sludge were 5-15 ng·L^-1 and 2-6 ng·g^-1, showing high sensitivity of the methods. The developed method has been successfully applied to evaluate the actual concentration levels of tetracyclines, quinolones, and sulfonamides in actual swine wastewater (maximum detected concentration of 87.377 μg·L^-1) and activated sludge (maximum detected concentration of 51242.3 ng·g^-1).

Imperatorin-pharmacological meaning and analytical clues: profound investigation

Imperatorin, a furanocoumarin derivative, has many documented pharmacological properties which make it a candidate for possible drug development. In this review, the activity on the central nervous system, the anticancer and antiviral properties and the influence on the cardiovascular system are described. The aim of this review is also to present an overview of the techniques used for the analysis, isolation, and separation of imperatorin from plant material from the practical perspective.

Multi-residue determination of 115 veterinary drugs and pharmaceutical residues in milk powder, butter, fish tissue and eggs using liquid chromatography-tandem mass spectrometry

A simple and sensitive multi-residue method for the determination of 115 veterinary drugs and pharmaceuticals, belonging in more than 20 different classes, in butter, milk powder, egg and fish tissue has been developed. The method involves a simple generic solid-liquid extraction step (solvent extraction, SE) with 0.1% formic acid in aqueous solution of EDTA 0.1% (w/v)-acetonitrile (ACN)-methanol (MeOH) (1:1:1, v/v) with additional ultrasonic-assisted extraction. Precipitation of lipids and proteins was promoted by subjecting the extracts at very low temperature (-23°C) for 12h. Further cleanup with hexane ensures fat removal from the matrix. Analysis was performed by liquid chromatography coupled with electrospray ionization and tandem mass spectrometry (LC-ESI-MS/MS). Two separate runs were performed for positive and negative ionization in multiple reaction monitoring mode (MRM). Particular attention was devoted to extraction optimization: different sample-to-extracting volume ratios, different concentrations of formic acid in the extraction solvent and different ultrasonic extraction temperatures were tested in butter, egg and milk powder samples. The method was also applied in fish tissue samples. It was validated, on the basis of international guidelines, for all four matrices. Quantitative analysis was performed by means of standard addition calibration. For over 80% of the analytes, the recoveries were between 50% and 120% in all matrices studied, with RSD values in the range of 1-18%. Limits of detection (LODs) and quantification (LOQs) ranged from 0.008 μg kg(-1) (oxfendazole in butter) to 3.15 μg kg(-1) (hydrochlorthiazide in egg). The evaluated method provides reliable screening, quantification, and identification of 115 veterinary drug and pharmaceutical residues in foods of animal origin and has been successfully applied in real samples.

Novel dispersive micro-solid-phase extraction combined with ultrahigh-performance liquid chromatography-high-resolution mass spectrometry to determine morpholine residues in citrus and apples

This paper presents a new analytical method for the determination of morpholine residues in citrus and apples using a novel dispersive micro-solid-phase extraction (DMSPE), followed by ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). Samples were extracted with 1% formic acid in acetonitrile/water (1:1, v/v) and then cleaned up using the DMSPE procedure. Morpholine from the extract was adsorbed to a polymer cation exchange sorbent and eluted with ammonium hydroxide/acetonitrile (3:97, v/v) through a 1 mL syringe with a 0.22 μm nylon syringe filter. All of the samples were analyzed by UHPLC-HRMS/MS on a Waters Acquity BEH hydrophilic interaction chromatography column using 0.1% formic acid and 4 mM ammonium formate in water/acetonitrile as the mobile phase with gradient elution. The method showed good linearity (R(2) > 0.999) in the range of 1-100 μg/L for the analyte. The limit of detection and limit of quantitation values of morpholine were 2 and 5 μg/kg, respectively. The average recoveries of morpholine from the citrus and apple samples spiked at three different concentrations (5, 20, and 100 μg/kg) were in a range from 78.4 to 102.7%.

Dispersive nano solid material-ultrasound assisted microextraction as a novel method for extraction and determination of bendiocarb and promecarb: response surface methodology

A new extraction method, based on Dispersive Nano-Solid material-Ultrasound Assisted Micro-Extraction (DNSUAME), was used for the preconcentration of the bendiocarb and promecarb pesticides in the water samples prior to high performance liquid chromatography (HPLC). The properties of NiZnS nanomaterial loaded on activated carbon (NiZnS-AC) are characterized by FT-IR, TEM, and BET. This novel nanomaterial showed great adsorptive ability towards the bendiocarb and promecarb pesticides. The effective variables such as the amount of adsorbent (mg: NiZnS-AC), the pH and ionic strength of sample solution, the vortex and ultrasonic time (min), the ultrasonic temperature (°C), and desorption volume (mL) are investigated by screening 2(7-4) experiments of Plackett-Burman (PB) design. The important variables optimized by using a central composite design (CCD) were combined by a desirability function (DF). At optimum conditions, the method has linear response over 0.0033-10 µg mL(-1) with detection limit between 0.0010 and 0.0015 µg mL(-1) with relative standard deviations (RSDs) less than 5.5% (n=3). The method has been successfully applied for the determination of the bendiocarb and promecarb pesticides in the water samples.

Hazardous impact and translocation of vanadium (V) species from soil to different vegetables and grasses grown in the vicinity of thermal power plant

The distribution of vanadium (V) species in soil (test soil), vegetables and grasses, collected from the vicinity of a thermal power plant has been studied. For comparison purpose soil (control soil), same vegetable and grass samples were collected from agricultural land devoid of any industrial area. A simple and efficient ultrasonic assisted extraction method has been developed for the extraction of V(5+) species from soil, vegetable and grass samples using Na(2)CO(3) in the range of 0.1-0.5 mol/L. For comparison purpose same sub samples were also extracted by conventional heating method. The total and V species were determined by electrothermal atomic absorption spectrometry using different modifiers. The validity of V(5+) and V(4+) determination had been confirmed by the spike recovery and total amount of V by the analysis of CRM 1570 (spinach leave) and sub samples of agricultural soil. The concentration of total V was found in the range of 90-215 and 11.4-42.3 μg/g in test and control soil samples, respectively. The contents of V(5+) and total V in vegetables and grasses grown around the thermal power plant were found in the range of 2.9-5.25 and 8.74-14.9 μg/g, respectively, which were significantly higher than those values obtained from vegetables and fodders grown in non exposed agricultural site (P<0.01). Statistical evaluations indicate that the sum of concentrations of V(5+) and V(4+) species was not significantly different from total concentration of V in same sub samples of vegetable, grass and soil of both origins, at 95% level of confidence.

Recent trends in the advanced analysis of bioactive fatty acids

The consumption of dietary fats have been long associated to chronic diseases such as obesity, diabetes, cancer, arthritis, asthma, and cardiovascular disease; although some controversy still exists in the role of dietary fats in human health, certain fats have demonstrated their positive effect in the modulation of abnormal fatty acid and eicosanoid metabolism, both of them associated to chronic diseases. Among the different fats, some fatty acids can be used as functional ingredients such as alpha-linolenic acid (ALA), arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), gamma-linolenic acid (GLA), stearidonic acid (STA) and conjugated linoleic acid (CLA), among others. The present review is focused on recent developments in FAs analysis, covering sample preparation methods such as extraction, fractionation and derivatization as well as new advances in chromatographic methods such as GC and HPLC. Special attention is paid to trans fatty acids due its increasing interest for the food industry.

Mercury-selenium species ratio in representative fish samples and their bioaccessibility by an in vitro digestion method

The potential toxicity of mercury (Hg) content in fish has been widely evaluated by the scientific community, with Methylmercury (MeHg) being the only legislated species (1 mg kg-1, maximum concentration allowed in predatory fish). On the other hand, selenium (Se) is recognized to decrease its toxicity when both elements are simultaneously administrated. In the present paper, the total content of Se and Hg and their species in fish of high consumption, such as tuna, swordfish, and sardine, have been evaluated. The percentage of MeHg is higher than 90% of total Hg content. The results show that, for all of them, the Se/Hg ratio is significantly higher than one, being the maximum ratio for sardine. As only studying the bioaccessible fraction the extent of a toxic effect caused by an element can be predicted, the bioaccessibility of both analytes through an in vitro digestion method has been carried out. The results show that MeHg in all fishes is very low bioaccessible in both gastric and intestinal digestion. Because the MeHg bioaccessible fraction might be correlated to the Se content, the potential toxicity cannot be only related to the total Hg content but also to Se/Hg ratio.

Rapid and sensitive determination of two degradation products of flumethrin in honey by ultrasonically assisted extraction and gas chromatography with electron capture detection

A rapid and sensitive method for the determination of 4-fluoro-3-phenoxybenzaldehyde cyanohydrin (FPBC) and 4-fluoro-3-phenoxy-benzaldehyde (FPB) in honey samples using ultrasonically assisted extraction and gas chromatography with electron capture detection (GC-ECD) has been developed. The different factors affecting the efficiency of the extraction were carefully optimized. The honey sample was extracted with a mixture of hexane and dichloromethane (v/v, 1:1) utilizing the ultrasonically assisted technique and cleaned up by solid-phase extraction on Oasis HLB cartridges. The eluate was evaporated to dryness and residues were reconstituted to 1.0 mL with hexane and determined by GC-ECD. The calibration curves of fortified samples showed acceptable linear response (R(2) >0.99) over a range of 3-100 ng/g for FPBC and FPB in seven replicate determinations of six concentrations, respectively, and analysis of variance (ANOVA) with a lack-of-fit test was performed to validate the regression data. Overall average recoveries ranged from 90.9 to 106.2% for honey samples. The detection limits were 0.9 ng/g for FPBC and 1.0 ng/g for FPB, respectively. This method can be successfully applied to routine determination of two degradation products of flumethrin in honey samples.

Pervaporation as interface between solid samples and capillary electrophoresis

A fully automated system for solid sample analysis has been developed by on-line coupling a pervaporation module with a capillary electrophoresis system using as interface a flow injection manifold and a modified capillary electrophoresis vial. The pervaporator allows leaching, formation of the volatile analytes and their removal by evaporation and diffusion through a membrane. The isolated analytes are on-line injected into the capillary electrophoresis system meanwhile the solid matrix remains in the pervaporator. By this approach biogenic amines have been determined in fish, meat and sausage. The detection limits (LOD) ranged between 0.2 and 0.6microg/ml, the quantification limits between 0.7 and 1.9microg/ml and the linear dynamic between 0.4 and 400microg/ml. The precision, expressed as relative standard deviation (RSD), ranged between 0.76 and 4.21% for repeatability and between 1.12 and 4.78% for within laboratory reproducibility. The errors, expressed as RSD for all compounds, ranged between 1.64 and 3.42%. The optimal pervaporation time and that necessary for the individual separation/detection of the target analytes are 14 and 12min, respectively. The analysis frequency is higher than 3h(-1) and the sample size 0.1g. A two-tailed t-test, used to compare the proposed method with that based on HPLC, yielded similar results for nine different samples.

Enzymatic probe sonication extraction of Se in animal-based food samples: a new perspective on sample preparation for total and Se speciation analysis

This paper describes a fast, simple and novel extraction method for total selenium and selenium species determination in food samples. Parameters influencing extraction, such as sonication time, extracting media, temperature, sample mass, ultrasound amplitude and sample/enzyme mass ratio were investigated. The enzymatic hydrolysis proposed, enhanced by probe sonication, allowed the quantitative extraction of selenium in chicken muscle, liver, kidney and feed (97, 93, 95 and 102%, respectively) in 2 min, maintaining the original Se-species integrity. Total Se content of the samples was determined using inductively coupled plasma mass spectrometry. Se-species were identified and quantified using high-performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry. Chromatographic analyses were carried out under two chromatographic conditions and led to the identification of SeMet in all samples. The accuracy of the proposed method was assessed using certified reference materials as well as microwave digestion. Potential advantages of the proposed method over traditional hydrolysis are speed, simplicity and safety of the procedure.

Effect of extraction method on the yield of furanocoumarins from fruits of Archangelica officinalis Hoffm

Optimal conditions for the extraction and analysis of furanocoumarins from fruits of Archangelica officinalis Hoffm. have been determined. The following extraction methods were used: exhaustive extraction in a Soxhlet apparatus, ultrasonication at 25 and 60 degrees C, microwave-assisted solvent extraction in open and closed systems, and accelerated solvent extraction (ASE). In most cases the yields of furanocoumarins were highest using the ASE method. The effects of extracting solvent, temperature and time of extraction using this method were investigated. The highest yield of furanocoumarins by ASE was obtained with methanol at 100-130 degrees C for 10 min. The extraction yields of furanocoumarins from plant material by ultrasonication at 60 degrees C and microwave-assisted solvent extraction in an open system were comparable to the extraction yields obtained in the time- and solvent-consuming exhaustive process involving the Soxhlet apparatus.

Influence of the extraction mode on the yield of some furanocoumarins from Pastinaca sativa fruits

Analysis of plant material is an important task in chemotaxonomical investigations, in search of plants with pharmacological activity or in standardisation of plant drugs. The choice of optimal conditions for the analysis of plant material and effect of extraction method on the yield of furanocoumarins from Pastinaca sativa fruits were examined. The following extraction methods were used in experiments: exhaustive extraction in Soxhlet apparatus, ultrasonification (USAE) at 25 and 60 degrees C, microwave-assisted solvent extraction in open and closed system (MASE) and accelerated solvent extraction (ASE). In most cases, the yield of furanocoumarins was highest by use of ASE method as well as by ultrasonification at 60 degrees C.

Fiber optic monitoring of carbamate pesticides using porous glass with covalently bound chlorophenol red

An optical fiber biosensor for the determination of the pesticides propoxur (Baygon) and carbaryl, two of the most commonly used carbamate insecticides in vegetable crops, is described. A pH indicator, chlorophenol red, is used as optical transducer of the inhibition of the enzyme acetylcholinesterase by the analytes. The biorecognition element is covalently immobilized onto controlled pore glass beads (CPG) and packed in a thermostatized bioreactor connected to a flow-through cell that contains CPG-immobilized chlorophenol red placed at the common end of a bifurcated fiber optic bundle. In the presence of a constant acetylcholine concentration, the colour of the pH sensitive layer changes and the measured reflectance signal can be related to the carbamate concentration in the sample solution. The performance of the biosensor has been optimized using a flow injection system. The linear dynamic range for the determination of carbaryl and propoxur spans from 0.8 to 3.0 mg l(-1) and from 0.03 to 0.50 mg l(-1), respectively. The detection limit (3 s) of the biosensor for propoxur (0.4 ng) is lower than that measured for carbaryl (25 ng). Reproducibility, stability and interference studies of the optical device are reported. The biosensor has been applied to the determination of propoxur in spiked vegetables (onion and lettuce) using ultrasound extraction, achieving recovery values between 93 and 95% for onion samples at the different concentration levels assayed.

Accelerated extraction of the fat content in cheese using a focused microwave-assisted soxhlet device

A fast method for hydrolysis and extraction of fat in cheese based on the use of a Soxhlet extractor assisted by microwaves is proposed. The use of this type of energy dramatically reduces the time required for both steps (namely, the hydrolysis time was decreased from 1 h to 10 min with avoidance of the neutralization step, and the extraction time was decreased from 6 h to 40 min), providing similar efficiency and reproducibility comparable to or better than that of the conventional Soxhlet methodology. In addition, the proposed method is cleaner than conventional Soxhlet, as 80-85% of the extractant is recycled. The determination of the fatty acid composition by gas-liquid chromatography and quantification of both polymer formation by high-performance size exclusion liquid chromatography and nonpolar triacylglycerol formation by thin-layer chromatography with flame ionization detection in the extracts obtained by the proposed method, conventional Soxhlet and Weibull-Berntrop procedures (Soxhlet with a prior hydrolysis step), showed that the quality of the extracts obtained by the proposed procedure is better than that of the conventional alternatives, possibly due to the shorter time required by the accelerated method.

Synergistic approaches based on nonchromatographic continuous separation techniques (solid-phase extraction and pervaporation) and chromatography couplings

Approaches based on continuous separation units coupled to either liquid or gas chromatography for improving the features of analytical methods are proposed. Examples of solid-phase separation-liquid chromatography for the determination of fat-soluble vitamins and their metabolites in clinical samples, and pervaporation-gas chromatography for the determination of volatile compounds in solid environmental samples are described. The clean-up and preconcentration effect achieved by the former coupling and the easy and effective solid-sample pretreatment in the latter clearly show their utility. The use of pervaporation as an advantageous alternative to headspace is demonstrated.