Rapid confirmatory method for the determination of sixteen synthetic growth promoters and bisphenol A in bovine milk using dispersive solid-phase extraction and liquid chromatography–tandem mass spectrometry

Bisphenol A in dairy products, amount, potential risks, and the various analytical methods, a systematic review

This systematic study deals with the amount of bisphenol A (BPA) in milk and dairy products, its analytical methods, and risk assessment. Milk is one of the drinks that has a high consumption. Bisphenol A can be present both in raw milk and its amount undergoes changes during the pasteurization process. This review was conducted by searching for the keywords Bisphenol A, BPA milk, dairy product, cheese, cream, butter, yogurt, measurement, detection, and analysis in different databases. The search was done in three databases, Scopus, PubMed and Science Direct. The largest number of studies on the determination of bisphenol A belonged to Asian and European countries. The amount of bisphenol A in milks was observed in the range from ND to 640 ng/mL. Furthermore, the amount of BPA in the tested cheese samples was observed in the ND range up to 6.1 ng/g and in the yogurt samples in the ND range up to 4.4 ng/g. The most used analytical method was based on liquid chromatography. The most used solvent for extraction was methanol or acetonitrile. HQ (Hazard Quotient) was also calculated in some studies. There was no risk in terms of milk consumption due to BPA contamination in extracted data.

Simultaneous determination of 58 glucocorticoid residues in milk by ultra-high performance liquid chromatography-tandem mass spectrometry

Abuse of glucocorticoid veterinary drugs in dairy industry can potentially threat milk safety and consequently influence human health. Here a reliable method for determination of 58 glucocorticoid drug residues in milk was established by combining solid phase extraction with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The analytes were extracted with acetonitrile and cleanup with EMR-Lipid lipid removal column. The analytes were chromatographically separated using Poroshell EC-C18 column and acquired by electrospray ionization with multiple-reaction monitoring (MRM) mode. The limit of quantification (S/N ≥ 10) ranged from 0.2 to 2.0 µg/kg and the limit of detection (S/N ≥ 3) ranged from 0.1 to 1.0 µg/kg. Average recoveries were from 71% to 113%, the relative standard deviations (RSDs) were less than 15%, and the correlation coefficients (R2) of calibration curves exceeded 0.99. The method was applied to detect twenty milk products obtained from local supermarkets including ten pasteurized milk and ten UHT milk. Two endogenous glucocorticoids, i.e. hydrocortisone and cortisone were detected but not exceed the maximum residue limits (MRLs).

An Electrochemical Sensor Based on Gold Nanodendrite/Surfactant Modified Electrode for Bisphenol A Detection

In the present work, we reported the simple way to fabricate an electrochemical sensing platform to detect Bisphenol A (BPA) using galvanostatic deposition of Au on a glassy carbon electrode covered by cetyltrimethylammonium bromide (CTAB). This material (CTAB) enhances the sensitivity of electrochemical sensors with respect to the detection of BPA. The electrochemical response of the modified GCE to BPA was investigated by cyclic voltammetry and differential pulse voltammetry. The results displayed a low detection limit (22 nm) and a linear range from 0.025 to 10 µm along side with high reproducibility (RSD = 4.9% for seven independent sensors). Importantly, the prepared sensors were selective enough against interferences with other pollutants in the same electrochemical window. Notably, the presented sensors have already proven their ability in detecting BPA in real plastic water drinking bottle samples with high accuracy (recovery range = 96.60%-102.82%) and it is in good agreement with fluorescence measurements.

Multi-Residue Method for the Analysis of Stilbene Estrogens in Milk

The rapid analysis of stilbene estrogens is crucially important in the environment, food and health sectors, but quantitation of lower detection limit for stilbene estrogens persists as a severe challenge. We herein described a homologous and sensitive fluorescence polarization (FP) assay based on estrogen receptor α ligand binding domain (ER-LBD) to monitor stilbene estrogens in milk. Under optimal conditions, the half maximal inhibitory concentrations (IC₅₀) of the FP assay were 9.27 nM, 12.94 nM, and 22.38 nM for hexestrol, dienestrol and diethylstilbestrol, respectively. And the corresponding limits of detection (LOD) values were 2.94 nM, 2.89 nM, and 3.12 nM. Finally, the assay was applied to determine the stilbenes in milk samples where the mean recoveries ranged from 95.76% to 112.78% and the coefficients of variation (CV) below 12.00%. Furtherly, we have focused our study on high cross-reactivity phenomena by using two in silico approaches, including molecular docking analysis and topology analysis. Overall, docking results show that several residues in the hydrophobic pocket produce hydrophobic interactions with the tested drug molecules, which contribute to the stability of their binding. In this paper, we conclude that the FP method is suitable for the rapid detection of stilbenes in milk samples, requiring no expensive analytical equipment or time-consuming sample preparation. This work offers a practical approach that applies bioscience technology in food safety testing and improves analytical speed and laboratory efficiency.

Dispersive Solid Phase Extraction for the Analysis of Veterinary Drugs Applied to Food Samples: A Review

To achieve analytical success, it is necessary to develop thorough clean-up procedures to extract analytes from the matrix. Dispersive solid phase extraction (DSPE) has been used as a pretreatment technique for the analysis of several compounds. This technique is based on the dispersion of a solid sorbent in liquid samples in the extraction isolation and clean-up of different analytes from complex matrices. DSPE has found a wide range of applications in several fields, and it is considered to be a selective, robust, and versatile technique. The applications of dispersive techniques in the analysis of veterinary drugs in different matrices involve magnetic sorbents, molecularly imprinted polymers, carbon-based nanomaterials, and the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method. Techniques based on DSPE permit minimization of additional steps such as precipitation, centrifugation, and filtration, which decreases the manipulation of the sample. In this review, we describe the main procedures used for synthesis, characterization, and application of this pretreatment technique and how it has been applied to food analysis.

Comparison of the Multiple Reaction Monitoring and Enhanced Product Ion Scan Modes for Confirmation of Stilbenes in Bovine Urine Samples Using LC-MS/MS QTRAP® System

In accordance with Commission Decision 2002/657/EC, confirmatory methods for the detection of prohibited substances should comply with specific requirements, including the criteria for confirmation. Two strategies: multiple reaction monitoring (MRM) and enhanced product ion (EPI) scanning functions were compared for confirming the anabolic compounds from synthetic stilbenes group in bovine urine samples. In the research, twenty samples fortified at the Recommended Concentration (RC) of 1 µg L⁻¹ with diethylstilbestrol, dienestrol and hexestrol were analyzed by liquid chromatography-tandem mass spectrometry on a QTRAP 5500 instrument. The analytical procedure, validated in accordance with the Commission Decision 2002/657/EC, used in the official control of hormones in Poland was applied. The validation parameters were in agreement with 2002/657/EC performance criteria. The effectiveness of MRM and EPI scanning modes for confirmation purposes was evaluated based on the percentage of the results confirmed. In all urine samples recorded in the MRM mode, the confirmation criteria (retention time, relative intensities between transitions) have been fulfilled. The presence of stilbenes in all urine samples using EPI scan mode was confirmed too as evidenced by a good matching of stilbenes spectra in the samples to the reference spectra with critical match factor above 0.7. The results of the research show that EPI scanning function provides the same effectiveness for confirmation of banned compounds as the mostly used MRM scan mode and can be an additional tool to confirm the doubtful case results in the analysis of hormones residues, even at such low concentration levels.

New method for the determination of parabens and bisphenol A in human milk samples using ultrasound-assisted extraction and clean-up with dispersive sorbents prior to UHPLC-MS/MS analysis

A sensitive and accurate analytical method for the determination of methyl-, ethyl-, propyl- and butylparaben and bisphenol A in human milk samples has been developed and validated. The combination of ultrasound-assisted extraction (UAE) and a simplified and rapid clean-up technique that uses sorbent materials has been successfully applied for the preparation of samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. The analytes were extracted from freeze-dried human milk samples using acetonitrile and ultrasonic radiation (three 15-min cycles at 70% amplitude), and further cleaned-up with C18 sorbents. The most influential parameters affecting the UAE method and the clean-up steps were optimized using design of experiments. Negative electrospray ionization (ESI) in the selected reaction monitoring (SRM) mode was used for MS detection. The use of two reactions for each compound allowed simultaneous quantification and identification in one run. The analytes were separated in less than 10min. Deuterium-labeled ethylparaben-d5 (EPB-d5) and deuterium-labeled bisphenol A-d16 (BPA-d16) were used as surrogates. The limits of quantification ranged from 0.4 to 0.7ngmL(-1), while inter- and intra-day variability was under 11.1% in all cases. In the absence of certified reference materials, recovery assays with spiked samples using matrix-matched calibration were used to validate the method. Recovery rates ranged from 93.8% to 112.2%. The proposed method was satisfactorily applied for the determination of four selected parabens and bisphenol A in human milk samples obtained from nursing mothers living in the province of Granada (Spain).

Analysis of potential migrants from plastic materials in milk by liquid chromatography-mass spectrometry with liquid-liquid extraction and low-temperature purification

A simple and fast analytical method was developed for the determination of six UV stabilizers (Cyasorb UV-1164, Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, and Tinuvin 1577) and five antioxidants (Irgafos 168, Irganox 1010, Irganox 3114, Irganox 3790, and Irganox 565) in milk. For sample preparation liquid-liquid extraction with low-temperature purification combined with centrifugation was used to remove fats, proteins, and sugars. After the cleanup step, the sample was analyzed with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). External standard and matrix calibrations were tested. External calibration proved to be acceptable for Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, Irganox 3114, and Irganox 3790. The method was successfully validated with matrix calibration for all compounds. Method detection limits were between 0.25 and 10 μg/kg. Accuracies ranged from 93 to 109%, and intraday precisions were <13%.

Synthesis and properties of magnetic molecularly imprinted polymers based on multiwalled carbon nanotubes for magnetic extraction of bisphenol A from water

Novel magnetic molecularly imprinted polymers based on multiwalled carbon nanotubes (MWNTs@MMIPs) with specific selectivity toward bisphenol A were synthesized using bisphenol A as the template molecule, methacrylic acid, and β-cyclodextrin as binary functional monomers and ethylene glycol dimethacrylate as the cross-linker. The MWNTs@MMIPs were characterized by Fourier transform infrared, vibrating sample magnetometer, and transmission electron microscopy. Batch mode adsorption experiment was carried out to investigate the specific adsorption equilibrium and kinetics of the MWNTs@MMIPs. The MWNTs@MMIPs exhibited good affinity with a maximum adsorption capacity of 49.26 μmol g(-1) and excellent selectivity toward bisphenol A. Combined with high-performance liquid chromatography analysis, the MWNTs@MMIPs were employed to extract bisphenol A in tap water, rain water, and lake water successfully with the recoveries of 89.8-95.4, 89.9-93.4, and 87.3-94.1%, respectively.

Determination of Trichlorfon Pesticide Residues in Milk via Gas Chromatography with μ-Electron Capture Detection and GC-MS

The pesticide trichlorfon is readily degraded under experimental conditions to dichlorvos. A method has therefore been developed by which residues of trichlorfon in milk are determined as dichlorvos, using gas chromatography with μ-electron capture detection. The identification of dichlorvos was confirmed by mass spectrometry. Milk was extracted with acetonitrile followed by centrifugation, freezing lipid filtration, and partitioning into dichloromethane. The residue after partitioning of dichloromethane was dissolved in ethyl acetate for gas chromatography. Recovery concentration was determined at 0.5, 1.0, and 2.0 of times the maximum permitted residue limits (MRLs) for trichlorfon in milk. The average recoveries (n = 6) ranged from 92.4 to 103.6%. The repeatability of the measurements was expressed as relative standard deviations (RSDs) ranging from 3.6%, to 6.7%. Limit of detection (LOD) and limit of quantification (LOQ) were 3.7 and 11.1 μg/l, respectively. The accuracy and precision (expressed as RSD) were estimated at concentrations from 25 to 250 μg/l. The intra- and inter-day accuracy (n = 6) ranged from 89.2%to 91% and 91.3% to 96.3%, respectively. The intra- and inter-day precisions were lower than 8%. The developed method was applied to determine trichlorfon in real samples collected from the seven major cities in the Republic of Korea. No residual trichlorfon was detected in any samples.

Analytical strategies based on chromatography-mass spectrometry for the determination of estrogen-mimicking compounds in food

Food safety can be compromised by the presence of a wide variety of substances, deriving from both natural and anthropogenic sources. Among these substances, compounds exhibiting various degrees of estrogenic activity have been widely studied in environmental samples, whereas less attention has been devoted to food matrices. The aim of the present review is to give a general overview on the recent analytical methods based on gas or liquid chromatography coupled to mass spectrometry for the determination of estrogen-like compounds in foods, including new developments, improvements and upcoming trends in the field. Attention will be focused on four representative groups of compounds, i.e. natural and synthetic estrogens, mycoestrogens, phytoestrogens, and alkylphenols.

Fragmentation of toxicologically relevant drugs in negative-ion liquid chromatography-tandem mass spectrometry

Negative-ion LC-MS analysis of drugs is applied far less frequently than positive-ion LC-MS. Data on the interpretation of negative-ion MS-MS spectra are even more scarce. Therefore, following the recent review on the class-specific fragmentation of toxicologically relevant compounds in positive-ion MS-MS, it was decided to perform a similar study in negative-ion MS-MS. To this end, a set of over 500 negative-ion MS-MS spectra was collected from three libraries applied in toxicological general unknown screening and systematic toxicological analysis. The compounds involved were classified by chemical and therapeutic class. The MS-MS spectra were manually interpreted and relevant interpretation data were searched for in the scientific literature. The emphasis in the discussion is on class-specific fragmentation, because discussing fragmentation of all individual compounds would take far too much space. Negative-ion MS-MS fragmentation is discussed for a wide variety of toxicologically relevant compounds, including dihydropyridine calcium channel blockers, diuretics, barbiturates, anti-inflammatory drugs, anti-diabetics, sulfonamide and betalactam antibiotics, and a number of classes of pesticides.

LC-MS/MS fast analysis of androgenic steroids in urine

The liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated to detect androgenic steroids: trenbolone, nortestosterone, boldenone, methylboldenone, testosterone, methyltestosterone, 17β-1-testosterone and their metabolites in bovine urine. Sample preparation before LC-MS/MS analysis involved an enzymatic hydrolysis with glucuronidase AS-HP, isolation of free hormones from urine on C(18) SPE column and purification of the extract using liquid-liquid extraction with n-pentane and SPE NH(2) column. For the chromatographic separation of steroids, the Poroshell 120-EC C18 column (150 × 2.1 mm, 2.7 μm) was used. Mass spectrometric measurement was achieved using the API 4000 triple quadrupole (QqQ) instrument with a TurboIon-Spray source operating in positive electrospray ionization mode. The procedure was validated according to the Decision 2002/657/EC. Recovery ranged from 76.5% to 118.9% for all examined compounds. The repeatability was below 20% and reproducibility did not exceed the 25%. The linearity was good for all analytes in the whole range of tested concentrations, as proved by the correlation coefficients greater than 0.99. The decision limit (CCα) ranged from 0.10 to 0.17 μg L(-1) for all analytes, whereas the detection capability (CCβ) ranged from 0.17 to 0.29 μg L(-1). The application of an innovative Poroshell column allowed for very good chromatographic separation of steroids with a much shorter time of analysis.