Development of a Method for the Analysis of Multiclass Antibiotic Residues in Milk Using QuEChERS and Liquid Chromatography–Tandem Mass Spectrometry

Current analytical strategies for the determination of quinolone residues in milk

Quinolones are potent antibacterial drugs extensively utilized for treating bacterial infections in poultry. However, the presence of quinolone antibiotic residues in milk is a matter of concern due to potential health risks and adverse effects on milk quality. This review provides an overview of current analytical strategies for the determination of quinolone residues in milk. Various sample preparation techniques, such as liquid-phase extraction, solid-phase extraction and QuEChERS, are discussed, along with detection methods including instrument-based detection, immune-based detection, and microbial detection. The advantages and limitations of each method are highlighted, as well as their applicability in different stages of milk production. Additionally, recent advancements in sample preparation and detection methods are presented. This comprehensive review aims to contribute to the development of accurate and reliable methods for the detection of quinolone residues in milk, ensuring the safety and quality of dairy products.

Preparation of a hydrophobic deep eutectic solvent and its application in the detection of quinolone residues in cattle urine

Enrichment for the detection of quinolone residues is usually cumbersome and requires large amounts of toxic organic reagents. Therefore, this study synthesized a low-toxicity hydrophobic deep eutectic solvent (DES) with DL-menthol and p-cresol, which was then characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and thermal analysis. A simple and rapid vortex-assisted liquid-liquid microextraction method was developed based on this DES for the extraction of eight quinolones from cattle urine. The optimal extraction conditions were screened by examining the DES volume, extraction temperature, vortex time, and salt concentration. Under the optimal conditions, the linear ranges of the eight quinolones were 1 ~ 100 μg/L with good linearity (r² was 0.998 ~ 0.999), and the limits of detection and quantification were 0.08 ~ 0.30 μg/L and 0.27 ~ 0.98 μg/L, respectively. The average extraction recoveries of spiked cattle urine samples were 70.13 ~ 98.50% with relative standard deviations below 13.97%. This method can provide a reference for the pre-treatment of quinolone residue detection.

Oxytetracycline Persistence in Uterine Secretion after Intrauterine Administration in Cows with Metritis

Simple Summary

Puerperal metritis in cows involves the acute inflammation of the uterus, which is often treated with antibacterial drugs. Restrictions on the use of antibiotics in veterinary medicine require the very precise selection of an antibiotic based on its pharmacokinetics and on sensitivity tests of pathogenic bacteria. This study aimed to evaluate the changes in oxytetracycline levels in uterine secretion over time after intrauterine administration in cows with metritis in relation to the sensitivity of pathogenic bacterial isolates. The concentrations of oxytetracycline in the uterine secretions were higher than the minimum inhibitory concentrations against pathogenic bacteria, provoking the infection of the uterus. Higher concentrations were measured in milk rather than in plasma. The intrauterine infusion of oxytetracycline for three consecutive days led to the alleviation of the inflammation and the restoration of the estrus cycle in cows. The local intrauterine administration of oxytetracycline requires the monitoring of the withdrawal time of milk to ensure consumer safety.

Abstract

Puerperal metritis in cows is often treated with antibacterial drugs. The prudent use of antibiotics in farm animals requires state-of-the-art knowledge of their pharmacokinetics and data from sensitivity tests of pathogenic bacteria. Changes in oxytetracycline levels in the uterine secretion over time after intrauterine administration in cows with metritis were evaluated in relation to the sensitivity of pathogenic bacterial isolates. Oxytetracycline levels in plasma, milk and uterine secretion were determined via LC–MS/MS analysis. Pathogenic bacteria were isolated and their sensitivity to oxytetracycline was determined. The concentrations of oxytetracycline in the uterine secretion were 433.79 (39.17–1668.76) µg·mL⁻¹ six hours after the third application at a dose of 8 mg/kg and 84.33 (1.58–467.55) µg·mL⁻¹ 96 h after the last treatment. These levels were higher than the minimum inhibitory concentrations—namely, between 4 and 64 µg·mL⁻¹—against pathogenic isolates Trueperella pyogenes, Streptococcus intermedius, Escherichia coli and Bacillus pumilis. Higher concentrations over time were measured in milk rather than in plasma, indicating the need to monitor the withdrawal time for milk. The intrauterine infusion of oxytetracycline for three consecutive days resulted in the successful treatment of metritis in terms alleviating inflammation and restoring the estrus cycle in cows.

Pretreatment Methods for the Determination of Antibiotics Residues in Food Samples and Detected by Liquid Chromatography Coupled with Mass Spectrometry Detectors: A Review

With the increasing use of antibiotics worldwide, antibiotic monitoring has become a topic of concern. After metabolizing of antibiotics in animals, the metabolites enter the environment through excreta or ingested by the human body via food chain that may exacerbate the emergence of antibiotic resistance and then threaten human's life. This article summarized several analytical methods used for the determination of antibiotics in recent 10 years. Due to the complex matrices and low concentration level of antibiotics in the food samples, a reliable analysis method is required to maximize the recovery rate. Several techniques like solid phase extraction (SPE), dispersive liquid-liquid microextraction (DLLME) and QuEChERS have been frequently used in the pretreatment process for analytes extraction and concentration. After the pretreatment, ultra-high performance liquid chromatography combined with mass spectrometry has been a reliable method for quantitative analysis and is able to determine multiple antibiotics simultaneously. This review also gives an overview about analytical conditions for antibiotics residues in different food samples and their method validation parameters.

Detection of multiple endocrine-disrupting chemicals in milk: Improved and safe HPLC-MS/MS method

Herein, an improved method for detecting the endocrine-disrupting chemicals in milk is presented, which is based on HPLC-MS/MS, coupled with a quick, effective, and safe method. The linearity of the proposed method was in the range of 0.05-100 μg/L, and all correlation coefficients were ≥0.9973. At three concentration levels, the spiked recoveries ranged from 77.7% to 107.5%, relative standard deviations ranged from 0.2% to 14.6%, limits of quantitation ranged from 0.1 to 40 μg/kg, limits of detection ranged from 0.03 to 13.3 μg/kg. The proposed method for the identification and quantitation of 26 endocrine disruptors present in milk is not only easy, fast, and cost-efficient but also provides a reference for the detection of various endocrine disruptors in milk and other dairy products. This article is protected by copyright. All rights reserved.

High-Coverage Screening of Sulfonamide Metabolites in Goat Milk by Magnetic Doped S Graphene Combined with Ultrahigh-Performance Liquid Chromatography-High-Resolution Mass Spectrometry

Currently, there are more than 1000 varieties of synthetic sulfonamides universally used as antibiotics causing severe results of potential carcinogenicity and drug resistance for human health due to excessive residue of animal-derived food. A facile and novel approach for untargeted screening of sulfonamides (SAs) and metabolites was proposed based on magnetic solid-phase extraction-ultrahigh-performance liquid chromatography-tandem high-resolution mass spectrometry (MSPE-UHPLC-HRMS). Compared with QuEChERS without the clean-up procedure and SPE in terms of matrix effect and absolute recovery, magnetic doped S graphene (S-doping level: 2.82%) synthesized via a solid-state microwave approach and the aggregation wrap mechanism was used as a novel adsorbent for nonspecific extraction of desired analytes by the noncovalent interaction between electron-deficient thiophene sulfur and electron donors such as amino or amide as well as π-π stacking interactions. Combined with variable data-independent acquisition, characteristic fragment-ion filtering (m/z 156.01138 or m/z 108.04439) and assignment of extracted-ion chromatograms of marked fragment ions were successfully utilized to screen the desired analytes and subsequently confirmed with the availability of reference standards. The optimized and validated approach for spiked 26 SAs and 9 metabolites in control goat milk demonstrated satisfactory accuracy (80.1-112.6%) and precision (RSDs < 6.4%) for matrix-matched standard addition. After applying suspect goat milk samples, untargeted SA analytes including sulfanilamide or an N⁴-acetylsulfamethazine metabolite with concentration ranging from 66.3 to 398.5 ng L^-1 were determined in 5 of 45 goat milk samples.

Multiple response optimization of a QuEChERS extraction and HPLC analysis of diclazuril, nicarbazin and lasalocid in chicken liver

A method for the simultaneous determination of three commonly used coccidiostats in chicken liver was developed, comprising a multi-residue QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction step, and a liquid chromatography-ultra violet-fluorescence (HPLC-UV/FL) analysis. The QuEChERS extraction was optimized using an experimental design approach that includes a screening step to obtain the critical variables, an optimization step using multiple response surface analysis and the calculation of a desirability parameter. The optimized method was validated with fortified samples, reaching an average recovery of 91% and an overall precision of 5.5% (mean of three analytes at three levels). Limits of detection calculated on fortified samples were 20 µg kg^-1 for lasalocid, 15 µg kg^-1 for nicarbazin and 120 µg kg^-1 for diclazuril. These values resulted at least one order of magnitude lower than the maximum allowed residue limit (MRL) of the studied coccidiostats for chicken liver.

Antibiotic Residues in Food: Extraction, Analysis, and Human Health Concerns

The abundant use of antibiotics leads to antibiotic residues in frequently consumed foods. Residual antibiotics in food may have adverse effects on humans by directly causing disease via low-dose exposure and indirect harm via antibiotic resistance. However, the current methods for antibiotic extraction and analysis in food have not yet formed a uniform standard, and only a few data exist regarding the residual antibiotic condition in various types of foods. Hence, we review the literature since 2008 to summarize analytical methods and residue status of antibiotics in food. Then, we discuss the causes of antibiotic residues in food and the possible hazards to human health. We hope that the joint efforts of the scientific community and political circles will lead to the formation of a unified standard for the extraction and analysis of antibiotics in food, to allow for comprehensive monitoring of residual antibiotics and ensure human health.

Simultaneous analysis of multiclass contaminants of emerging concern in sediments by liquid chromatography with tandem quadrupole mass spectrometry

A quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction and simultaneous dispersive solid-phase extraction (dSPE) clean-up method was developed for contaminants of emerging concern (CECs) in sediment samples. Hydration with a phosphate buffer (pH 2.0) and salting out with NaCl and MgSO₄ facilitated the extraction and liquid-liquid portioning of the aqueous and organic phases. Cleanup of the extracts was achieved by florisil and C18 (1:1) sorbents in dSPE with minimal compromise of the analytes. The extracts were clean enough for determination by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The procedure was validated for preservatives, blood lipid regulators, analgesics and anti-inflammatory drugs, plasticizers, and other classes of CECs in sediment matrix spiked at 6 levels between 1- and 40-fold concentrations for CECs of varying analytical sensitivities. The recovery values were generally between approximately 27 and 120% and the relative standard deviation (%RSD) values were below 20% at 10- , 20- , and 40-fold spiking levels, albeit the recoveries for some analytes dropped at low spike concentrations. The method showed high sensitivity where the method detection limits (MDLs) were at low ppb levels for the majority of the analytes that ranged between 0.002 and 1.93 µg/kg. The method performance was also compared with well-established US Environmental Protection Agency (USEPA) Method 1694 by analyzing sediment samples collected from Yundang Lagoon (Xiamen, China) with field-incurred CEC residues. The sediment samples were detected with residues of parabens, gemfibrozil, ketoprofen, naproxen, fenoprofen, diclofenac, miconazole, carbamazepine, benzophenon-3, glibenclamide, sildinafil citrate, and some bisphenol analogues. Environ Toxicol Chem 2019;38:1409-1422. © 2019 SETAC.

Development of a High Pressure Liquid Chromatography with Diode Array Detection Method for the Determination of Four Tetracycline Residues in Milk by Using QuEChERS Dispersive Extraction

QuEChERS (quick, easy, cheap, effective, rugged and safe) dispersive extraction was applied for the extraction of tetracyclines (oxytetracycline, tetracycline, chlorotetracycline and doxycycline) from milk. Target analytes were determined by an accurate and sensitive chromatographic analytical method, which was validated in terms of 2002/6572/EC decision. The analytes were separated on an Orbit 100C4 (5 μm, 250 × 4.0 mm) analytical column under a gradient mobile phase composed of a mixture of 0.01 M oxalic acid, 10−4 M Na2EDTA and acetonitrile. For the extraction of isolated compounds from sorbent, a methanol and 0.01 M oxalic acid mixture (1:1 v/v) was used, leading to relative recovery rates from 83.07% to 106.3% at concentration levels in the range 100–200 μg/kg. The within-laboratory reproducibility, expressed as a relative standard deviation, was <15.5%. Decision limits ranged between 100.3 μg/kg and 105.6 μg/kg and the detection capability varied between 100.6 μg/kg and 109.7 μg/kg. Ruggedness was evaluated by following the Youden approach, in terms of milk mass, sorbent mass, centrifugation time, vortex time, type and volume of organic solvents and evaporation temperature.

Exploring the rumen fluid metabolome using liquid chromatography-high-resolution mass spectrometry and Molecular Networking

The rumen primary and secondary metabolite content is intimately related to its community of bacteria, protozoa, fungi, archaea and bacteriophages, ingested feed and the host. Despite the myriad of interactions and novel compounds to be discovered, few studies have explored the rumen metabolome. Here, we present the first study using ultra-high performance liquid chromatography tandem mass-spectrometry and Molecular Networking approach, and various extraction methods on the cell-free rumen fluid of a non-lactating Holstein cow. Putative molecules were annotated based on accurate fragmentation matching the Global Natural Products Social Molecular Networking library, public spectral libraries, or annotated manually. The combination of five extraction methods resulted on 1,882 molecular features observed. Liquid-liquid extraction resulted on the highest molecular features abundance, 1,166 (61.96% of total). Sixty-seven compounds were annotated using Global Natural Products Social Molecular Networking library and public libraries, such as hydrocinnamic and azelaic acid, and monensin. Only 3.56% of molecular features (67) observed had positive match with available libraries, which shows the potential of the rumen as reservoir of novel compounds. The use of untargeted metabolomics in this study provided a snapshot of the rumen fluid metabolome. The complexity of the rumen will remain long unknown, but the use of new tools should be encouraged to foster advances on the rumen metabolome.

QuEChERS extraction for multi-residue analysis of PCBs, PAHs, PBDEs and PCDD/Fs in biological samples

In this study, a fast and rugged method is presented for the analysis of PCBs, PAHs, PBDEs and PCDD/Fs in biological tissues using a simple Quick, Easy, Cheap, Efficient, Rugged and Safe (QuEChERS) extraction and a clean-up by Gel Permeation Chromatography (GPC) and silica Solid Phase Extraction (SPE). Development was performed on blue mussels (Mytilus edulis) and Atlantic salmon (Salmo salar) for evaluation of two ranges of lipid and water content of biological tissues. Statistical validation was performed with Atlantic salmon samples. Forty-five PAHs were analyzed including the priority list of the US EPA and the European Union with 41 PCBs, 24 PBDEs and 17 PCDD/Fs. Instrumental analyses were performed on Gas Chromatography - High Resolution Mass Spectrometry (GC-HRMS). Accuracy was evaluated for PCBs and PCDD/Fs with a certified reference material furnished by the National Research Council Canada (NRCC) and also compared with results obtained by the conventional Soxhlet extraction. Statistical validation showed recoveries for PCBs, PAHs, PBDEs and PCDD/Fs close to 100% with average Relative Standard Deviation (RSD) lower than 10% and internal standard recoveries in the range of 70% with average RSD ranging from 5-15%. Average calculated Method Detection Limits (MDLs) were lower than 0.05μg/Kg for PCBs, 0.2μg/Kg for PAHs and PBDEs and 1ng/Kg for PCDD/Fs. The method is a faster and cheaper alternative to the time-consuming conventional method that has been used in most environmental laboratories.

Optimizing Mass Spectrometry Analyses: A Tailored Review on the Utility of Design of Experiments

Mass spectrometry (MS) has emerged as a tool that can analyze nearly all classes of molecules, with its scope rapidly expanding in the areas of post-translational modifications, MS instrumentation, and many others. Yet integration of novel analyte preparatory and purification methods with existing or novel mass spectrometers can introduce new challenges for MS sensitivity. The mechanisms that govern detection by MS are particularly complex and interdependent, including ionization efficiency, ion suppression, and transmission. Performance of both off-line and MS methods can be optimized separately or, when appropriate, simultaneously through statistical designs, broadly referred to as "design of experiments" (DOE). The following review provides a tutorial-like guide into the selection of DOE for MS experiments, the practices for modeling and optimization of response variables, and the available software tools that support DOE implementation in any laboratory. This review comes 3 years after the latest DOE review (Hibbert DB, 2012), which provided a comprehensive overview on the types of designs available and their statistical construction. Since that time, new classes of DOE, such as the definitive screening design, have emerged and new calls have been made for mass spectrometrists to adopt the practice. Rather than exhaustively cover all possible designs, we have highlighted the three most practical DOE classes available to mass spectrometrists. This review further differentiates itself by providing expert recommendations for experimental setup and defining DOE entirely in the context of three case-studies that highlight the utility of different designs to achieve different goals. A step-by-step tutorial is also provided.