Trace Analysis of Multiclass Antibiotics in Food Products by Liquid Chromatography-Tandem Mass Spectrometry: Method Development

Ultrasensitive detection of chlortetracycline in animal-origin food using molecularly imprinted electrochemical sensor based on SnS2/ZnCo-MOF and AuNPs

The chlortetracycline (CTC) residue in food poses a threat to human health. Therefore, developing sensitive, convenient and selective analytical methods for CTC detection is crucial. This study innovatively uses tin disulfide/bimetallic organic framework (SnS2/ZnCo-MOF) nanocomposites in conjunction with gold nanoparticles (AuNPs) to co-modify a glassy carbon electrode (GCE). Further, a molecularly imprinted polymer (MIP)-based electrochemical sensing platform Au-MIP/SnS2/ZnCo-MOF/Au/GCE (AZG) was fabricated for selective CTC detection. SnS2/ZnCo-MOF enhanced the stability and surface area of the AZG sensor. The presence of AuNPs facilitated electron transport between the probe and the electrode across the insulating MIP layer. The fixation of AuNPs and MIP via electropolymerization enhanced the selective recognition of this sensor and amplified its output signal. The AZG sensor demonstrated a wide linear detection range (0.1-100 μM), low detection limit (0.072 nM), and high sensitivity (0.830 μA μM-1). It has been used for detecting CTC in animal-origin food with good recovery (96.08%-104.60%).

Simultaneous and on-line detection of organic and heavy metal components in water using a novel nebulization-assisted injection plasma ionization triple quadruple mass spectrometry instrument

BACKGROUND

The global release of organic and heavy metal components into natural water bodies is a major concern for the environment and human health. The assessment of water quality relies on analyzing organic and heavy metal components qualitatively and quantitatively. Real-time identification of organic and metal components in water systems requires different analytical techniques due to varying measurement requirements. Thus, on-line detecting both organic compounds and heavy metals in ambient water systems simultaneously using a single instrumentation setup presents a significant challenge.

RESULTS

In this study, an analytical technique of nebulization-assisted injection plasma ionization mass spectrometry (NI-PIMS) was developed. This novel method enables the simultaneous detection of heavy metals and organic compounds in water system with high sensitivity, which has been demonstrated by the limit of quantification (LOQ) values below 1.0 μg/L for the three sterols (Enrofloxacin, ciprofloxacin, and clenbuterol) and three heavy metals (Pb, Ba, and Cd). Moreover, the method was successfully applied to rapidly analyze real water samples from urban and rural areas in China. The analytical results are available in less than 0.5 min, and only a few microliters of sample are required for each analysis.

SIGNIFICANCE AND NOVELTY

As far as we know, this is the first report of on-line simultaneous analysis of organic compounds and heavy metals in a water system using a single mass spectrometry instrument. Compared to traditional methods, NI-PIMS demonstrates higher efficiency, sensitivity, no or lower sample preparation, and less sample consumption. The advancement and widespread use of this technology are expected to enhance the effectiveness of mass spectrometers, broaden the applications, and play an important role in complex sample analysis in fields such as atmospheric science, environmental science, and earth science.

Isothermal Reciprocal Catalytic DNA Circuit for Sensitive Analysis of Kanamycin

Inappropriate use of veterinary drugs can result in the presence of antibiotic residues in animal-derived foods, which is a threat to human health. A simple yet efficient antibiotic-sensing method is highly desirable. Programmable DNA amplification circuits have supplemented robust toolkits for food contaminants monitoring. However, they currently face limitations in terms of their intricate design and low signal gain. Herein, we have engineered a robust reciprocal catalytic DNA (RCD) circuit for highly efficient bioanalysis. The trigger initiates the cascade hybridization reaction (CHR) to yield plenty of repeated initiators for activating the rolling circle amplification (RCA) circuit. Then the RCA-generated numerous reconstituted triggers can reversely stimulate the CHR circuit. This results in a self-sufficient supply of numerous initiators and triggers for the successive cross-invasion of CHR and RCA amplifiers, thus leading to exponential signal amplification for the highly efficient detection of analytes. With its flexible programmability and modular features, the RCD amplifier can serve as a universal toolbox for the high-performance and accurate sensing of kanamycin in buffer and food samples including milk, honey, and fish, highlighting its enormous promise for low-abundance contaminant analysis in foodstuffs.

Developing a novel magnetic organic polymer for selective extraction and determination of 16 macrolides in water and honey samples

A novel magnetic organic polymer Fe3O4@SiO2@Tb-PDAN was designed and synthesized, which was used as an adsorbent for magnetic solid-phase extraction (MSPE) of 16 macrolides (MALs) in water and honey. The synthesized adsorbent was characterized using techniques including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Then several parameters of the extraction process were further optimized. Under the optimized conditions, an MSPE-LC-MS/MS method was established for extraction and determination of 16 MALs, which showed good linearity (r ≥ 0.999), low limits of detection (0.001-0.012 μg L-1 for water and 0.001-0.367 μg kg-1 for honey) and satisfactory recoveries (70.02-118.91%) with the relative standard deviations (RSDs) lower than 10.0%. This established method was then successfully applied to detect MALs in real samples, which suggested that Fe3O4@SiO2@Tb-PDAN was a potential magnetic adsorbent for efficient extraction and analysis of MALs.

A modified QuEChERS method based on a reduced graphene oxide-coated melamine sponge for multiresidue analysis of veterinary drugs in mutton by UPLC-MS/MS

The development of different matrix adsorbents is a research focus in the multiresidue analysis of veterinary drugs in foods. In this study, a novel elastic matrix adsorbent based on a reduced graphene oxide-coated melamine sponge was prepared and applied in matrix purification for the simultaneous determination of 52 veterinary drugs in mutton by UPLC-MS/MS. Efficient and convenient matrix removal was achieved through simple soaking and squeezing. Good linearities with determination coefficients ≥0.999 and low matrix effects ≤±13% were obtained in the range of 10-500 μg·kg-1. The obtained recoveries ranged from 63.7% to 109.5% at three spiked levels (10, 50, and 100 μg·kg-1), with relative standard deviations ≤8.1%. Low LODs and LOQs were obtained in ranges of 0.02-2.0 μg·kg-1 and 0.05-5.0 μg·kg-1, respectively. Based on the comprehensive results, our developed method showed good applicability in the analysis of multiresidues in various foods.

Simultaneous determination of 13 sulfonamides at trace levels in soil by modified QuEChERS with HPLC-MS/MS

The pretreatment of samples was vital for enhancing the sensitivity and accuracy of analytical methods. An efficient and sensitive method, based on modified QuEChERS with high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of the 13 sulfonamides (SAs) in soil, was developed. After extraction by sonication with methanol, the clean-up procedure was achieved using QuEChERS with a primary secondary amine (PSA). The quantification of the 13 SAs was performed by HPLC-MS/MS in electrospray ionization (ESI) and multiple reaction monitoring (MRM) modes. Under optimized conditions, the standard solution exhibited good linearity within the range of 0.01-0.5 μg mL-1. The limits of detection and the limits of quantification of the developed method were 0.007-0.030 μg kg-1 and 0.022-0.101 μg kg-1, respectively. The spiked recoveries for the 13 SAs were in the range of 74.5-111.7% with RSD less than 15%. Furthermore, the developed method was successfully applied for the determination of SAs in real soil samples. The above results showed that the proposed method would be an ideal analytical method for SAs in environmental ecological research.

A novel multifunctional magnetically recyclable BiOBr/ZnFe2O4-GO S-scheme ternary heterojunction: Photothermal synergistic catalysis under Vis/NIR light and NIR-driven photothermal detection of tetracycline

The threat of tetracycline (TC) to human health has become a significant issue that cannot be disregarded. Herein, in order to achieve effective degradation and high-sensitivity detection of TC, BiOBr/ZnFe2O4-GO (BOB/ZFO-GO) S-scheme heterojunction nanocomposites (NCs) have been prepared using hydrothermal method. GO with high light absorption capacity accelerated the electron transfer between BiOBr and ZnFe2O4 nanocrystals and extended the light absorption region of BOB/ZFO NCs. The optimal GO addition of BOB/ZFO-GO NCs could degrade TC solution of 10 mg/L in 80 min and have a high reaction rate constant (k) of 0.072 min-1 under visible/NIR light. According to calculations, the non-metal photocatalyst (BOB/ZFO-GO(2)) with the best degradation performance had a photothermal conversion efficiency of up to 23%. Meanwhile, BOB/ZFO-GO NCs could be recycled by magnetic field. The excellent photocatalytic and photothermal performance could be maintained even after several cycles. In addition, a photothermal detection sensor based on a photothermal material/specific recognition element/tetracycline sandwich-type structure was constructed for the trace detection of TC concentration with a detection limit as low as 10-4 ng/mL. This research provides a unique idea for the multi-functionalization of photocatalysts and has a wide range of potential applications for the identification and treatment of organic wastewater.

Gold nanoparticles as colorimetric probes in food analysis: Progress and challenges

The rapid, sensitive and reliable food safety control is urgently needed due to the harmful effects of the food contaminants on human health. Colorimetric approach has exhibited promising potential for the detection of food contaminants due to their easy preparation, rapid detection, high sensitivity, and naked-eye sensing. In recent years, AuNPs-based colorimetric probes have been extensively explored for food analysis. The present article reviews the development of AuNPs-based colorimetric probes for colorimetric sensing and their applications in food analysis. It generally summarizes the properties of AuNPs and introduces the preparation and functionalization methods of AuNPs. An overview of the colorimetric sensing mechanisms of AuNPs-based probes and their applications in analysis of food contaminants are also provided. Although AuNPs-based colorimetric probes show many advantages in detection of food contaminants, challenges remain in terms of complexity of food matrices, multiple analytes detection in a single go, and testing conditions interference.

Human daily dietary intakes of antibiotic residues: Dominant sources and health risks

Antibiotic use in crops is an emerging concern, however, human exposure to antibiotics residues through consumption of plant-derived food has generally been neglected. This study is a comprehensive evaluation based on full consideration of exposure sources and analysis for nearly 100 antibiotics. A total of 58 antibiotic compounds were detected in drinking water (n = 66) and 49 in food samples (n = 150) from Shenzhen, China. The probable daily intake from drinking water and food consumption based on the total concentration of all the detected antibiotic compounds was 310, 200, and 130 ng/kg-body weight/day for preschool children, adolescents, and adults, with a maximum of up to 1400, 970 and 530 ng/kg-bw/day, respectively. Consumption of plant-derived food products, rather than animal-derived food, was the main source of the daily intake, and drinking water was a minor source. Risk assessment suggested a potentially unacceptable health risk from daily intake of norfloxacin, lincomycin and ciprofloxacin. Further research is warranted to alleviate food safety concerns related to antibiotic residues in plant-derived and animal-derived food products.

Rapid determination of 103 common veterinary drug residues in milk and dairy products by ultra performance liquid chromatography tandem mass spectrometry

A multi-residue method has been developed for the identification and quantification of 103 common veterinary drug residues in milk and dairy Products. This method was based on QuEChERS with dispersive solid-phase where C18 sorbent and anhydrous sodium sulfate were used to sample purification. After evaporation and reconstitution, the samples were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry. The mean recovery results were all higher than 60% except ampicillin, pipemidic acid, enoxacin, and estriol, and the relative standard deviation was <20.0%. The limit of quantification ranged between 0.1 and 5 μg/kg for milk and between 0.5 and 25 μg/kg for milk powder. It was successfully used to detect residues of veterinary drug in real samples. This study proposes a simple and fast analytical method for monitoring multi-class veterinary drug residues to ensure food safety.

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 fluoroquinolone and sulfonamide residues in poultry eggs in Kunming city, southwest China

Antibiotic residues contained in poultry eggs pose threat to human health. However, the classes and concentrations of antibiotics in poultry egg in southwestern China is unknown due to insufficient monitoring and research. A total of 513 egg samples were collected from supermarkets and farm markets in Kunming city in 2020 and the levels of 7 antibiotics were analyzed using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. The linear correlation coefficients were above 0.990 for all antibiotics tested. The limits of detection and limits of quantification in poultry eggs were 0.002 to 0.010 μg/g and 0.007 to 0.033 μg/g, respectively. The average recoveries of the 7 analytes from poultry egg samples were 80.00 to 128.01%, with relative standard deviations of less than 13.97%. A total of 93 (18.13%) samples tested positive for antibiotics, with the highest concentration being 2.48 μg/g. The concentration range of ofloxacin, danofloxacin, difloxacin, sulfadimethoxine, sulfamonomethoxine, sulfamethoxypyridazine, and sulfamethoxazole in poultry eggs was 0.01 to 0.37 μg/g, 0.06 to 0.48 μg/g, 0.05 to 0.29 μg/g, 0.03 to 0.16 μg/g, 0.06 to 1.00 μg/g, 0.05 to 0.37, and 0.07 to 2.48 μg/g, respectively. Sulfamonomethoxine was detected from hen eggs with the highest concentration level at 1.00 μg/g. Sulfamethoxazole was detected with the highest concentration level from both duck and quail eggs, at 1.87 and 2.48 μg/g, respectively. The antibiotic with the highest residue level in pheasant eggs was danofloxacin, which was 0.37 μg/g. Sulfamethoxypyridazine was identified in 30 samples with the highest positive rate of 5.85%, sulfadimethoxine was identified in 3 samples with the lowest positive rate of 0.58%. We observed that 7 targeted antibiotic residues in quail eggs and 3 targeted antibiotic residues in pheasant eggs. We also found that there were antibiotic residues in free-range hen eggs and the concentration was not low. The antibiotic with the highest residue level in free-range eggs was sulfamonomethoxine, which was 1.00 μg/g. These findings suggest that continual antibiotic residue monitoring of poultry eggs is essential in China.

Survey on Antibiotic Residues in Egg Samples in Italy

The presence of antibiotic residue in eggs is a current issue due to the increasingly important phenomenon of antibiotic resistance. A multiclass, confirmatory method for the determination of seventy-three antimicrobial agents (amphenicols, cephalosporins, diaminopyrimidines, lincosamides, macrolides, penicillins, pleuromutilins, quinolones, sulfonamides, and tetracyclines) with liquid chromatography high-resolution mass spectrometry was applied to 200 egg samples collected from 119 Italian farms during the years 2018–2021.