Evaluation of a new modified QuEChERS method for the monitoring of carbamate residues in high-fat cheeses by using UHPLC-MS/MS

Development and validation of a micro-QuEChERS method with high-throughput enhanced matrix removal followed with UHPLC-QqQ-MS/MS for analysis of raspberry ketone-related phenolic compounds in adipose tissues

Raspberry ketone (RK) is a major flavor compound in red raspberries, and it has been marketed as a popular weight-loss dietary supplement with high potential in accumulating in fatty tissues. However, challenges in extracting and characterizing RK and its associated phenolic compounds in fatty tissues persist due to the complex matrix effect. In this work, we reported a high-throughput sample preparation method for RK and 25 related phenolic compounds in white adipose tissues using an improved micro-scale QuEChERS (quick, efficient, cheap, easy, rugged and safe) approach with enhanced matrix removal (EMR)-lipid cleanup in 96-well plates, followed by UHPLC-QqQ-MS/MS analysis. The absolute recovery was 73-105% at the extraction step, and achieved 71-96% at the EMR cleanup step. The EMR cleanup removed around 66% of total lipids in the acetonitrile extract as profiled by UHPLC-QTOF-MS/MS. The innovative introduction of a reversed-phase C18 sorbent into the extract significantly improved the analytes' recovery during SpeedVac drying. The final accuracy achieved 80-120% for most analytes. Overall, this newly developed and validated method could serve as a powerful tool for analyzing RK and related phenolic compounds in fatty tissues.

Effect of grape pomace from red cultivar 'Nero d'Avola' on the microbiological, physicochemical, phenolic profile and sensory aspects of ovine Vastedda-like stretched cheese

AIMS

The purpose of this study was to functionalize an ovine stretched cheese belonging to 'Vastedda' typology with red grape pomace powder (GPP) of Nero d'Avola cultivar and to characterize the microbiological, physicochemical, phenolic profile and sensory characteristics of the final cheeses.

METHODS AND RESULTS

Before cheeses production, GPP was characterized for its microbiological profile, antibacterial activity and polyphenolic content. No colonies of bacteria and yeasts were detected in the GPP. GPP showed a large inhibition spectrum against spoilage and pathogenic bacteria. Three classes of polyphenolic compounds belonging to flavan-3-ols, flavonol and phenolic acids were identified. Two cheeses [0 and 1% (w w^-1 ) of GPP] were produced with pasteurized ewe's milk and commercial starter cultures. Plate counts and randomly amplified polymorphic DNA analysis demonstrated the ability of the starter strains to drive the fermentation process in the presence of GPP. GPP enrichment resulted in an increase of protein, phenolic compounds, sensory traits and reduced fat.

CONCLUSIONS

GPP addition to cheese represents an optimal strategy for the valorization of winemaking by-products and to obtain polyphenol-enriched cheese.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study allowed to achieve an ovine cheese with specific physicochemical, nutraceutical and sensorial characteristics able to enlarge the functional dairy product portfolio.

Food Bioactive Compounds and Emerging Techniques for Their Extraction: Polyphenols as a Case Study

Experimental studies have provided convincing evidence that food bioactive compounds (FBCs) have a positive biological impact on human health, exerting protective effects against non-communicable diseases (NCD) including cancer and cardiovascular (CVDs), metabolic, and neurodegenerative disorders (NDDs). These benefits have been associated with the presence of secondary metabolites, namely polyphenols, glucosinolates, carotenoids, terpenoids, alkaloids, saponins, vitamins, and fibres, among others, derived from their antioxidant, antiatherogenic, anti-inflammatory, antimicrobial, antithrombotic, cardioprotective, and vasodilator properties. Polyphenols as one of the most abundant classes of bioactive compounds present in plant-based foods emerge as a promising approach for the development of efficacious preventive agents against NCDs with reduced side effects. The aim of this review is to present comprehensive and deep insights into the potential of polyphenols, from their chemical structure classification and biosynthesis to preventive effects on NCDs, namely cancer, CVDs, and NDDS. The challenge of polyphenols bioavailability and bioaccessibility will be explored in addition to useful industrial and environmental applications. Advanced and emerging extraction techniques will be highlighted and the high-resolution analytical techniques used for FBCs characterization, identification, and quantification will be considered.

Multivariate optimization of a new LC-MS/MS method for the determination of 156 pesticide residues in milk and dairy products

BACKGROUND

Pesticides are widely utilized worldwide to control undesirable life forms during the planting procedure in agriculture. But they can pollute the nature and jeopardize human wellbeing. Additionally, on account of high resistance and biological activity; pesticides are able to accumulate in living organs and lead to acute and long-term negative effects along with toxicity. Milk and dairy products constitute an important part of a humans' diet since they contain fundamental supplements and nutrients, however they may also be the source of unhealthy components including pesticides. Therefore efficient, accurate and sensitive determination methods must be improved to quantify pesticide residues in these food samples.

RESULTS

Multivariate optimization strategy was employed to optimize an efficient and robust liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for the determination of 156 pesticide residues in milk and dairy products. Three independent variables considered and their levels in the Box-Behnken design were as follows: initial percentage of eluent A in mobile phase (30, 40, 50%), flow rate of the mobile phase (0.1, 0.2, 0.3 mL min^-1 ), and ammonium formate concentration in mobile phase (0.0, 0.5, 1.0 mmol L^-1 ). Under optimized conditions, average recoveries of target analytes were obtained in the range of 70.38% to 119.04%. Detection and quantification limits ranged from 0.06 to 2.70 μg kg^-1 and from 0.22 to 8.10 μg kg^-1 , respectively.

CONCLUSION

The validated method was successfully implemented to the analysis of 20 milk and dairy products including cream, cheese and yogurt. This method could be applied in many laboratories to reduce analysis time and cost. © 2020 Society of Chemical Industry.

A multi-class multi-residue method for the analysis of polyether ionophores, tetracyclines and sulfonamides in multi-matrices of animal and aquaculture fish tissues by ultra-high performance liquid chromatography tandem mass spectrometry

An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) based multiclass multi-residue method for the simultaneous analysis of 5 polyether ionophores, 4 tetracycline and 10 sulfonamides in animal and aquaculture fish tissues was developed and validated. Sample extraction and clean-up were based on a modified QuEChERS method. The method was validated using an in-house validation based on performance characteristics modified from Commission Decision 2002/657/EC. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were minimised by the use of matrix-matched calibrations. Recoveries of analytes were generally satisfactory and typically fell between 80% and 113%. The repeatability and intermediate reproducibility measured as relative standard deviations were in most cases less than 15% (n = 63). The decision limit (CCα) and detection capability (CCβ) ranged from 110.7 to 125.8 and 121.5 to 151.7 µg kg^-1 for tetracyclines, 113.4 to 118.3 and 116.8 to 126.5 µg kg^-1 for sulfonamides and 50.8 to 52.4 and 51.5 to 55.6 µg kg^-1 for polyether ionophores, respectively. The method displayed its fitness for purpose through satisfactory results obtained in international proficiency testing schemes. The method was applied to animal and aquaculture fish tissues obtained from different sources in South Africa. Polyether ionophores were predominantly detected in samples in the range 4.26-290.10 µg/kg. Oxytetracycline was found in one porcine liver sample; however, none of the targeted analytes were present above the detection limit in the aquaculture samples.

Determination of sulfonylurea pesticide residues in edible seeds used as nutraceuticals by QuEChERS in combination with ultra-high-performance liquid chromatography-tandem mass spectrometry

This work proposes a novel Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method in combination with ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of sulfonylurea residues in edible seeds. The chromatographic separation of nine sulfonylureas was accomplished in less than 5.5 min, using a Luna Omega C₁₈ column (50 × 2.1 mm, 1.6 µm). Mobile phase was supplied at 0.55 mL min^-1 and consisted of 0.01% (v/v) aqueous acetic acid as eluent A and a mixture methanol/acetonitrile (80/20, v/v) as eluent B. Column temperature was established at 25 °C. A QuEChERS procedure was investigated as sample treatment for sulfonylureas extraction and sample clean-up. Different clean-up agents (i.e. PSA, Z-Sep⁺, EMR-Lipid and C¹⁸) were evaluated, selecting Z-Sep⁺ (25 mg) as the best option. The proposed method provided an extraction efficiency greater than 86.2%, while absolute matrix effect was lower than 50.1%. Matrix-matched calibration curves were required for analyte quantification. The analytical method was characterized according to SANTE/11813/2017 guideline, and including limits of detection and quantification, precision, and trueness. Linear dynamic ranges were established from 5 to 150 µg kg^-1 for all analytes. Linearity (R² ≥ 0.9974) and precision in terms of repeatability and intermediate precision (relative standard deviation ≤ 14.7%) are reported. The reporting limit was established at 5 µg kg^-1, which is above the limits of quantification of the proposed method (≤ 1.64 µg kg^-1) and below the maximum residue levels currently established by European legislation. In general, trueness is within the range of 70-120%. Despite greater recoveries were obtained at the reporting limit (i.e. 120-138%), relative standard deviations lower than 20% were obtained at this concentration level, so fulfilling the requirements of SANTE/11813/2017 guideline. This work represents the first analytical method intended for the analysis of sulfonylureas in sunflower, pumpkin and chia seeds, which are complex matrices due to their high content of fat as well as of growing interest due to their current commercialization as nutraceuticals.

QuEChERS - Fundamentals, relevant improvements, applications and future trends

The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method is a simple and straightforward extraction technique involving an initial partitioning followed by an extract clean-up using dispersive solid-phase extraction (d-SPE). Originally, the QuEChERS approach was developed for recovering pesticide residues from fruits and vegetables, but rapidly gained popularity in the comprehensive isolation of analytes from different matrices. According to PubMed, since its development in 2003 up to November 2018, about 1360 papers have been published reporting QuEChERS as extraction method. Several papers have reported different improvements and modifications to the original QuEChERS protocol to ensure more efficient extractions of pH-dependent analytes and to minimize the degradation of labile analytes. This analytical approach shows several advantages over traditional extraction techniques, requiring low sample and solvent volumes, as well as less time for sample preparation. Furthermore, most of the published studies show that the QuEChERS protocol provides higher recovery rate and a better analytical performance than conventional extraction procedures. This review proposes an updated overview of the most recent developments and applications of QuEChERS beyond its original application to pesticides, mycotoxins, veterinary drugs and pharmaceuticals, forensic analysis, drugs of abuse and environmental contaminants. Their pros and cons will be discussed, considering the factors influencing the extraction efficiency. Whenever possible, the performance of the QuEChERS is compared to other extraction approaches. In addition to the evolution of this technique, changes and improvements to the original method are discussed.

Simultaneous detection of multiple hydroxylated polychlorinated biphenyls from biological samples using ultra-high-performance liquid chromatography with isotope dilution tandem mass spectrometry

We established a method for the separation and detection of nine hydroxylated polychlorinated biphenyls in whole blood and urine samples using ultra high performance liquid chromatography coupled with electrospray negative ionization tandem mass spectrometry. Clean-up procedures involved a filtration step, and optimization involved a pretreatment step consisting of a simple liquid-liquid extraction using hydrated silica-gel chromatography (5%). Nine hydroxylated polychlorinated biphenyls were separated on an ultra high performance liquid chromatography HSS T3 column using a gradient elution program of 2 mmol ammonium formate aqueous solution (A) and methanol (B). Recovery ranged from 84.0 to 105.4% for the nine different hydroxylated polychlorinated biphenyls in urine with three spiked levels of 0.1, 1, and 2 ng and from 73.5 to 98.6% for the blood with spiked levels of 0.2, 1, and 2 ng. The relative standard deviations were <8.7% (n = 6), and the limits of detection in urine and whole blood for the nine hydroxylated polychlorinated biphenyls were in the range of 1.5-4 and 20-100 pg/g, respectively. This analytical method may enable the simultaneous detection of various hydroxylated polychlorinated biphenyls from complex tissue matrices.

Ultra high performance liquid chromatography with tandem mass spectrometry method for determining dinotefuran and its main metabolites in samples of plants, animal-derived foods, soil, and water

An ultra high-performance liquid chromatography with tandem triple quadrupole mass spectrometry residue method was developed and validated for the quantification and identification of dinotefuran and its main metabolites 1-methyl-3-(tetrahydro-3-furylmethyl) urea and 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine in fruit (watermelon), vegetable (cucumber), cereal (rice), animal-derived foods (milk, egg, and pork), soil, and water. The samples were extracted with acetonitrile containing 15% v/v acetic acid and purified with dispersive solid-phase extraction with octadecylsilane, primary secondary amine, graphitized carbon black, or zirconia-coated silica prior to analysis. The method had an excellent linearity (R²  ≥ 0.9942, 1-500 μg/L) and satisfactory recoveries (73-102%) at five spiked levels (0.001, 0.01, 0.05, 0.5, and 2 mg/kg) with intra- or interday precision in the range of 0.8-9.5% and 3.0-12.8% for the three compounds in the eight matrices. The limits of quantification were 10 μg/kg for 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine and 1 μg/kg for 1-methyl-3-(tetrahydro-3-furylmethyl) urea and dinotefuran. The applicability of the developed method was demonstrated by determining the occurrence of dinotefuran, 1-methyl-3-(tetrahydro-3-furylmethyl) guanidine, and 1-methyl-3-(tetrahydro-3-furylmethyl) urea in various samples from plants, animal-derived foods, and the environment. From 80 samples, 70 contained dinotefuran (0.8-11.7 μg/kg), among which six also contained 1-methyl-3-(tetrahydro-3-furylmethyl) urea (water and rice, 0.5-0.9 μg/kg).