Analysis of additives in dairy products by liquid chromatography coupled to quadrupole-orbitrap mass spectrometry

Quick and high-throughput quantification of β-agonist residues in bovine liver, meat, milk, kidney, poultry, and egg using dispersive solid phase extraction

A reliable liquid chromatography coupled to quadrupole-Orbitrap high-resolution mass spectrometry (LC-Q-Orbitrap HRMS) method was developed for the simultaneous identification and quantification of 13 β-agonist residues in bovine liver, meat, milk, kidney, poultry, and egg. Dispersive-solid phase extraction (d-SPE) using acetonitrile (ACN) was used to prepare the samples. The analyte in the extracts was separated on a reversed-phase Accucore aQ (50 mm × 2.1 mm, 2.6 μm) using a mobile phase of an aqueous solution containing 2 mM ammonium acetate and acetonitrile (ACN) 0.1 % formic acid. The method was validated in accordance with Commission Implementing Regulation (CIR) EU 2021/808 at six different concentrations ranging from 0.1 to 5 μg/kg. The mean recoveries ranged from 65 to 94 %, while repeatability and reproducibility values were all below 13 %. The linearity, as correlation coefficients (R2) ranged from 0.9955 to 0.9999. The decision limit (CCα) and detection capability (CCβ) ranges were 0.11-0.13 µg/kg and 0.12-0.15 µg/kg, respectively. The limits of detection (LOD) and limits of quantification (LOQ) were in the range of 0.004-0.048 μg/kg and 0.010-0.075 μg/kg, respectively. Of the 180 samples that were collected from local markets in Egypt, 21.11 % had β-agonist residues. The mean concentration (µg/kg) and detection frequency (%) of the most frequently found β-agonist in the samples were as follows: terbutaline (2.63 µg/kg and 90 %), ractopamine (5.14 µg/kg and 23.3 %). The method's applicability was verified by successfully completing two rounds of proficiency testing (PT).

Unlocking Potentially Therapeutic Phytochemicals in Capadulla (Doliocarpus dentatus) from Guyana Using Untargeted Mass Spectrometry-Based Metabolomics

Doliocarpus dentatus is thought to have a wide variety of therapeutic phytochemicals that allegedly improve libido and cure impotence. Although a few biomarkers have been identified with potential antinociceptive and cytotoxic properties, an untargeted mass spectrometry-based metabolomics approach has never been undertaken to identify therapeutic biofingerprints for conditions, such as erectile dysfunction, in men. This study executes a preliminary phytochemical screening of the woody vine of two ecotypes of D. dentatus with renowned differences in therapeutic potential for erectile dysfunction. Liquid chromatography-mass spectrometry-based metabolomics was used to screen for flavonoids, terpenoids, and other chemical classes found to contrast between red and white ecotypes. Among the metabolite chemodiversity found in the ecotype screens, using a combination of GNPS, MS-DIAL, and SIRIUS, approximately 847 compounds were annotated at levels 2 to 4, with the majority of compounds falling under lipid and lipid-like molecules, benzenoids and phenylpropanoids, and polyketides, indicative of the contributions of the flavonoid, shikimic acid, and terpenoid biosynthesis pathways. Despite the extensive annotation, we report on 138 tentative compound identifications of potentially therapeutic compounds, with 55 selected compounds at a level-2 annotation, and 22 statistically significant therapeutic biomarkers, the majority of which were polyphenols. Epicatechin methyl gallate, catechin gallate, and proanthocyanidin A2 had the greatest significant differences and were also relatively abundant among the red and white ecotypes. These putatively identified compounds reportedly act as antioxidants, neutralizing damaging free radicals, and lowering cell oxidative stress, thus aiding in potentially preventing cellular damage and promoting overall well-being, especially for treating erectile dysfunction (ED).

Development, validation and application of multi-class methods for the analysis of food additives by liquid chromatography coupled to tandem mass spectrometry

Food additives are used in numerous food products and are characterised by various physicochemical properties. In European member states, their use in food is regulated by the European Union. This work aimed to develop an accurate and high-throughput analytical method enabling the simultaneous determination of additives from different functional classes to facilitate controls and generate occurrence data for exposure assessments. The QuEChERS principle was applied due to its ease of implementation and flexibility to adjust to various food matrices. However, very polar substances could not be extracted with sufficient recoveries. Consequently, an alternative basic methanol sample-preparation methodology was developed. After sample preparation, the obtained extracts were analysed using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Overall, the developed methodology allowed the quantification of 27 additives from the functional classes of colours, sweeteners, preservatives, and antioxidants in various foods (e.g. beverages, dairies, processed meals). The methods were also validated in terms of selectivity, linearity, matrix effect, limit of quantification, accuracy, repeatability, and intra-laboratory reproducibility. Finally, the methods were successfully applied to eighty-four actual samples. All additives were found below authorised levels. However, irregularities were spotted in labelling.

Analysis of synthetic antioxidants in salmon silage using QuEChERS extraction method followed by determination by LC-MS/MS; a single-laboratory validation study

A new method was developed and in-house validated to determined ethoxyquin (EQ), butylated hydroxyanisole (BHA) and propyl gallate (PG) in fish silage and fish oil used for production of animal feed. Sample pre-treatment comprises use of QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction and gives extracts for liquid chromatography-triple quadrupole mass spectrometry analysis without matrix interferences. The results allow quantification of the antioxidants in all matrices by using deuterated internal standards and calibration curves made in solvent, as well as establishing low detection limits (0.012-0.015 mg/kg) and quantification limits (0.040-0.050 mg/kg) needed regarding the recent suspension of EQ as feed additive within the European Union. The proposed method was validated in terms of linearity, accuracy (relative error, ±1.4%), precision (RSD, ≤2.7%) and recovery (matrix effect, 97-101%) where all the parameters show acceptable results according to recognized guidelines (including EuraChem) within method validation. Combined expanded measurement uncertainty was estimated with a coverage factor of 2 by including all contributors to analytical variation, showing results of ±15% or better. The combined QuEChERS and LC-MS/MS method was successfully applied to salmon silage samples and their corresponding aqueous and oil fractions.

A Comprehensive Screening and Identification of Genistin Metabolites in Rats Based on Multiple Metabolite Templates Combined with UHPLC-HRMS Analysis

Genistin, an isoflavone belonging to the phytoestrogen family, has been reported to possess various therapeutic effects. In the present study, the genistin metabolites in rats were investigated by UHPLC-LTQ-Orbitrap mass spectrometer in both positive and negative ion modes. Firstly, the data sets were obtained based on data-dependent acquisition method and then 10 metabolite templates were established based on the previous reports. Then diagnostic product ions (DPIs) and neutral loss fragments (NLFs) were proposed to efficiently screen and ascertain the major-to-trace genistin metabolites. Meanwhile, the calculated Clog P values were used to identify the positional isomers with different retention times. Consequently, a total of 64 metabolites, including prototype drug, were positively or putatively characterized. Among them, 40 metabolites were found according to the templates of genistin and genistein, which was the same as the previous research method. After using other metabolite templates, 24 metabolites were added. The results demonstrated that genistin mainly underwent methylation, hydrogenation, hydroxylation, glucosylation, glucuronidation, sulfonation, acetylation, ring-cleavage and their composite reactions in vivo biotransformation. In conclusion, the research not only revealed the genistein metabolites and metabolic pathways in vivo comprehensively, but also proposed a method based on multiple metabolite templates to screen and identify metabolites of other natural compounds.

Liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry based method for target analysis and suspect screening of non-ionic surfactants in textiles

In this study, we describe a high-throughput and sensitive method for textiles analysis, using liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry (LC-Q-Orbitrap HRMS), for the simultaneously quantitative analysis of 40 target alkylphenol polyethoxylates (APEO) oligomers with reference standards and screening of 160 alcohol polyethoxylates (AEO) oligomers without standards in textiles. The APEOs contain nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) with an EO number of ethylene oxide of 1-20, while AEOs focus on C₁₁EOs-C₁₈EOs with an EO number of 1-20. After ultrasonic extraction in methanol, the extract was directly separated using a core-shell CORTECS C₁₈⁺ column and analyzed by Full MS/dd-MS² (data dependent acquisition) scan in ESI positive mode. Two best sensitivity experimental conditions for APEOs with short EO chains (AP(EO)_1-2) and long EO chains (AP(EO)_3-20) were investigated, respectively. Most APEO oligomers had wide concentration ranges and the correlation coefficients (R²) were higher than 0.999. The limit of quantitation (LOQ) values for NP(EO)_3-20 oligomers ranges from 16.00 to 52.80μg/kg and for OP(EO)_3-20 oligomers is from 2.40 to 8.00μg/kg. LOQ for NP(EO)₁ and NP(EO)₂, OP(EO)₁ and OP(EO)₂ was 2.40mg/kg and 0.24mg/kg, 1.20mg/kg and 0.16mg/kg, respectively. The average recovery for each APEO oligomer in cotton and polyester matrix was between 78% and 110% at three spiked levels and the relative standard deviation (RSD%) was below 10%. As to AEOs suspects, a HRMS compound database containing 160 AEO oligomers was built and several parameters such as exact m/z, isotopic patterns, predicted product ions and predicted retention time were used for screening and confirmation. The established method was successfully applied for analysis of 40 commercial textile samples. Compared with OPEOs, NPEOs, especially NP(EO)_3-15 oligomers, were widely detected in samples and the total concentration ranged from 1.56 to 1376.31mg/kg. AEOs were also found in most samples, among which C_12-14, C₁₆ and C₁₈ compounds appeared more frequently and the EO chains mainly ranged from 3 to 15.