Optimization and application of parallel solid-phase extraction coupled with ultra-high performance liquid chromatography–tandem mass spectrometry for the determination of 11 aminoglycoside residues in honey and royal jelly

Colorimetric aptasensor for tobramycin based on a highly stabilized aptamer-enhanced enzyme-mimicking activity of iron oxide/graphene oxide nanospheres

Antibiotic contaminants in food are associated with detrimental health issues, and thus, the design of rapid and reliable detection methods to monitor them is in high demand. Although colorimetric aptamer sensing methods can achieve accurate and quick visual read-out analysis, they still have morphological defects that affect the detection efficiency and stability of the aptasensor. Hence, a simple and highly selective iron oxide/graphene oxide (Fe3O4/GO) nanospheres was developed and modified with an aptamer as nanozymes for colorimetric detection of tobramycin (Tob). Due to the electrostatic and π-π stacking interaction between the aptamer and the spherical Fe3O4/GOs nanozyme, the catalytic activity of the nanozyme was enhanced by the robust affinity between the aptamer and the 3,3',5,5'-tetramethylbenzidine (TMB) substrate. However, the presence of Tob could obstruct the catalytic activity through the specific binding of aptamer to Tob and the detachment of aptamer from the surface of the Fe3O4/GO, causing a low catalytic activity. Based on this strategy, a visual and quantitative detection for Tob was achieved with a detection limit of 70.7 nM. The proposed aptasensor demonstrated high selectivity, ease of operation, and potential application in food samples with satisfactory recoveries of 98.4-108.5 %. Therefore, this proposed method has great prospects for monitoring food safety and could be applied for sensing varied antibiotics by just switching the target-specific aptamer.

Boronic acid-functionalized magnetic covalent organic frameworks based solid-phase extraction coupled with hydrophilic interaction chromatography-tandem mass spectrometry for the determination of trace gentamicin residues in milk

Boric acid-functionalized magnetic covalent organic frameworks (Fe3O4-TpBD-B) with large surface area and high porosity were prepared and applied for magnetic solid-phase extraction adsorbent of gentamicin from milk before UPLC-MS/MS detection. By utilizing a new HILIC chromatographic column with zwitterionic sulfoalkyl betaine stationary phase based on ethyl bridged hybrid particles (BEH), isomers of gentamicin (C1, C1a, and C2+C2a components). The developed methods demonstrated good linearity (R2 > 0.99), acceptable accuracy and good precision (<10 %), and low limit of quantitation (1.59 ng mL⁻1 for C1, 1.52 ng mL⁻1 for C1a and 2.72 ng mL⁻1 for C2+C2a). In addition, this method has been effectively applied to the analysis of real milk samples.

Determination of Aminoglycosides by Ion-Pair Liquid Chromatography with UV Detection: Application to Pharmaceutical Formulations and Human Serum Samples

Aminoglycosides (AGs) represent a prominent class of antibiotics widely employed for the treatment of various bacterial infections. Their widespread use has led to the emergence of antibiotic-resistant strains of bacteria, highlighting the need for analytical methods that allow the simple and reliable determination of these drugs in pharmaceutical formulations and biological samples. In this study, a simple, robust and easy-to-use analytical method for the simultaneous determination of five common aminoglycosides was developed with the aim to be widely applicable in routine laboratories. With this purpose, different approaches based on liquid chromatography with direct UV spectrophotometric detection methods were investigated: on the one hand, the use of stationary phases based on hydrophilic interactions (HILIC); on the other hand, the use of reversed-phases in the presence of an ion-pairing reagent (IP-LC). The results obtained by HILIC did not allow for an effective separation of aminoglycosides suitable for subsequent spectrophotometric UV detection. However, the use of IP-LC with a C18 stationary phase and a mobile phase based on tetraborate buffer at pH 9.0 in the presence of octanesulfonate, as an ion-pair reagent, provided adequate separation for all five aminoglycosides while facilitating the use of UV spectrophotometric detection. The method thus developed, IP-LC-UV, was optimized and applied to the quality control of pharmaceutical formulations with two or more aminoglycosides. Furthermore, it is demonstrated here that this methodology is also suitable for more complex matrices, such as serum, which expands its field of application to therapeutic drug monitoring, which is crucial for aminoglycosides, with a therapeutic index ca. 50%.

Contamination of Honeybee (Apis mellifera L.) Royal Jelly by Pesticides and Sample Preparation Methods for Its Determination: A Critical Appraisal

Pesticides can easily enter the food chain, harming bee populations and ecosystems. Exposure of beehive products to various contaminants has been identified as one of the factors contributing to the decline in bee populations, and multiple food alerts have been reported. Despite this fact, royal jelly, a valuable bee product with nutritional and functional properties, has received less attention in this context. Pesticide residues of different chemical class can contaminate royal jelly when foraging bees collect pollen or nectar from pesticide-treated flowers, or in some cases, due to its frequent and inappropriate use in the treatment of mites in beehives. To monitor this issue and also make it more reliable, it is crucial to develop effective sample preparation methods for extracting pesticides from royal jelly for subsequent analysis. In this context, this review provides information about sample preparation methods (solid-phase extraction, solvent extraction, and QuEChERS-quick, easy, cheap, effective, rugged and safe) and analytical methods that have been validated or improved to extract and analyze pesticides, respectively, in royal jelly samples of different origins. Finally, future perspectives are discussed. With this background, we aim to provide data that can guide future research related to this topic.

Residue analysis of 10 aminoglycoside antibiotics in aquatic products by multiwalled carbon nanotubes combined with mixed-mode ion exchange liquid chromatography-tandem mass spectrometry

An ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed for simultaneous determination of 10 kinds of aminoglycosides in edible parts of aquatic products. The samples were extracted with 10 mmol/L potassium dihydrogen phosphate buffer solution, then the pH value of the extract was adjusted to neutral by sodium hydroxide. Half volume of the extract was loaded onto multiwalled carbon nanotubes cartridge. All the target compounds were separated on a mixed-mode ion exchange column and detected by ultra-high-performance liquid chromatography-tandem mass spectrometry with electrospray in the positive ionization mode. Under optimized conditions, this method had a good linearity with a squared correlation coefficient > 0.999. For neomycin, the limit of detection and limit of quantification were 5.0 μg/kg and 10.0 μg/kg, respectively; for hygromycin B and apramycin, values were 2.0 μg/kg and 5.0 μg/kg, respectively; for the other seven kinds of aminoglycosides, values were 1.0 μg/kg and 2.0 μg/kg, respectively. The average recoveries presented 75.8%-107.2% with intra- and interday reproducibility ranging between 3.8% and 12.5%. The method was rapid with good separation and sharp peak shapes, had the characteristicsis of high accuracy and good precision, and was suitable for simultaneous determination of 10 kinds of aminoglycosides in aquatic products.

Polyvinyl alcohol electrospun nanofiber membrane based solid-phase extraction for monitoring administered aminoglycoside antibiotics in various animal-derived foods

This work aims to develop a widely applicable method to monitor administered AGs in various animal-derived food samples to ensure food safety. A polyvinyl alcohol electrospun nanofiber membrane (PVA NFsM) was synthesized and employed as solid-phase extraction (SPE) sorbent, in combination with UPLC-MS/MS, for the simultaneous detection of ten AGs in nine types of animal-derived food samples. PVA NFsM exhibited excellent adsorption performance for the targets (with an adsorption rate of over 91.09%), good matrix purification ability (with a reduction of 7.65%-77.47% in matrix effect after SPE), and good recyclability (can be reused 8 times). The method displayed a linear range of 0.1-25000 μg/kg and attained limits of detection for AGs were 0.03-15 μg/kg. Spiked samples demonstrated a recovery of 91.72%-100.04% with a precision of<13.66%. The practicality of the developed method was verified by testing multiple actual samples.

Analysis of Aminoglycoside Antibiotics: A Challenge in Food Control

Aminoglycosides are a widely used group of antibiotics in veterinary medicine. However, misuse and abuse of these drugs can lead to residues in the edible tissues of animals. Due to the toxicity of aminoglycosides and the exposure of consumers to the emergence of drug resistance, new methods are being sought to determine aminoglycosides in food. The method presented in this manuscript describes the determination of twelve aminoglycosides (streptomycin, dihydrostreptomycin, spectinomycin, neomycin, gentamicin, hygromycin, paromomycin, kanamycin, tobramycin, amikacin, apramycin, and sisomycin) in thirteen matrices (muscle, kidney, liver, fat, sausages, shrimps, fish honey, milk, eggs, whey powder, sour cream, and curd). Aminoglycosides were isolated from samples with extraction buffer (10 mM NH₄OOCH₃, 0.4 mM Na₂EDTA, 1% NaCl, 2% TCA). For the clean-up purpose, HLB cartridges were used. Analysis was performed using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) with a Poroshell analytical column and a mobile phase of acetonitrile and heptafluorobutyric acid. The method was validated according to Commission Regulation (EU) 2021/808 requirements. Good performance characteristics were obtained for recovery, linearity, precision, specificity, and decision limits (CCα). This simple and high-sensitivity method can determine multi-aminoglycosides in various food samples for confirmatory analysis.

Liquid Chromatography-Tandem Mass Spectrometry Analysis of Aminoglycosides in Foods Using an Ethylene-Bridged Hybrid Zwitterionic Stationary Phase and Hydrophilic-Lipophilic-Balanced Solid-Phase Extraction Cartridges

This work aimed to develop an analytical method for the screening of multiple aminoglycoside residues in foods of animal origin using an ethylene-bridged hybrid (BEH) particle-based sulfoalkylbetaine stationary phase. The effects of chromatographic conditions on the separation of 17 aminoglycosides have been systematically investigated. Sample preparation and mass spectrometry detection have also been investigated and optimized. In contrast to high buffer concentrations in the mobile phase required for silica-based sulfoalkylbetaine stationary phases, a moderate buffer concentration (20 mM) provided the optimal separation of 17 aminoglycosides with the BEH sulfoalkylbetaine stationary phase. The developed method has been evaluated in milk, beef, pork, liver, and honey samples with good performance for retention, selectivity, sensitivity, linearity, precision, and accuracy. The majority of the limit of quantitation estimated with the matrix was less than 25 μg/kg. The overall accuracy across five matrices was in the range from 96 to 111%, with standard deviations of less than 19%.

Affinity-Based Analysis Methods for the Detection of Aminoglycoside Antibiotic Residues in Animal-Derived Foods: A Review

With the increasingly serious problem of aminoglycoside antibiotic residues, it is imperative to develop rapid, sensitive and efficient detection methods. This article reviews the detection methods of aminoglycoside antibiotics in animal-derived foods, including enzyme-linked immunosorbent assay, fluorescent immunoassay, chemical immunoassay, affinity sensing assay, lateral flow immunochromatography and molecular imprinted immunoassay. After evaluating the performance of these methods, the advantages and disadvantages were analyzed and compared. Furthermore, development prospects and research trends were proposed and summarized. This review can serve as a basis for further research and provide helpful references and new insights for the analysis of aminoglycoside residues. Accordingly, the in-depth investigation and analysis will certainly make great contributions to food safety, public hygiene and human health.

An Aptamer Affinity Column for Extraction of Four Aminoglycoside Antibiotics from Milk

This article introduces the aptamer affinity column (AAC) with nucleic acid aptamer as an affinity ligand for the extraction of four aminoglycoside antibiotics (AGs). The AAC was prepared by loading the aptamer functionalized Sepharose into an extraction column, which was conjugated by covalent binding between NHS-activated Sepharose and amino-modified aptamers with a coupling time of 2 h. After the sample solution flowed through the AAC, the AGs were retained because of the affinity between the AGs and aptamer, then AGs were eluted and analyzed by UPLC-MS/MS. Under the optimized conditions, the maximum adsorption of AGs on the AAC could reach 8.0 μg. Moreover, the proposed AAC could be reused more than 20 times. The resultant AAC that conjugated with the aptamer was successfully applied in the enrichment and purification of four AGs in a milk sample and good recovery results in the range of 83.3–98.8% were obtained (with RSD in the range of 0.6–5.8%). The proposed AAC for recognition of multi-target AGs exhibited good enrichment and purification effects, showing great application potential for targets with their related aptamers.

Novel Electrochemical Aptasensor Based on Ordered Mesoporous Carbon/2D Ti3C2 MXene as Nanocarrier for Simultaneous Detection of Aminoglycoside Antibiotics in Milk

Herein, a novel electrochemical aptasensor using a broad-spectrum aptamer as a biorecognition element was constructed based on a screen-printed carbon electrode (SPCE) for simultaneous detection of aminoglycoside antibiotics (AAs). The ordered mesoporous carbon (OMC) was firstly modified on 2D Ti₃C₂ MXene. The addition of OMC not only effectively improved the stability of the aptasensor, but also prevented the stacking of Ti₃C₂ sheets, which formed a good current passage for signal amplification. The prepared OMC@Ti₃C₂ MXene functioned as a nanocarrier to accommodate considerable aptamers. In the presence of AAs, the transport of electron charge on SPCE surface was influenced by the bio-chemical reactions of the aptamer and AAs, generating a significant decline in the differential pulse voltammetry (DPV) signals. The proposed aptasensor presented a wide linear range and the detection limit was 3.51 nM. Moreover, the aptasensor, with satisfactory stability, reproducibility and specificity, was successfully employed to detect the multi-residuals of AAs in milk. This work provided a novel strategy for monitoring AAs in milk.

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.

Environmentally friendly analysis of sulphonamides in Brazilian honey through automated and miniaturised sample preparation coupled with LC-MS/MS

Increased use of environmentally friendly practices has become a trend in science because of the current awareness regarding climate change and related issues. Similarly for analytical chemistry, considering the development of greener methods for reducing the use of reagents and samples and also toxic waste generation. To meet such goals, automation, and miniaturisation of sample preparation-a well-recognised laborious and time-consuming analytical step-are two promising strategies. This work associates the greener aspects of miniaturisation and the performance of automated sample preparation. Therefore, we proposed an analytical method using a miniaturised extraction column for pre-concentrating sulphamerazine, sulphamethazine, sulphamethoxazole, sulphadimethoxine, sulphathiazole, and sulphachlorpyridazine from honey and cleaning-up the samples. Several variables were optimised: extractive phase, loading flow, loading phase, and loading time. Under optimised conditions, the method showed adequate linearity between 5.0 and 60 ng g^-1 with R > 0.99, and also good selectivity and recovery (114.6-124.1%) which are acceptable according to Brazilian legislation. Intra and inter-day precision were in the range 3.0-5.0%. Although sulphonamides were detected in one of the eight commercial honey samples, the value was below the established MRL. The method showed efficiency, while also exhibiting greener characteristics resulting from miniaturisation and automation, representing a promising environmentally friendly alternative for conventional sample preparation methods.

Analytical Strategies for LC-MS-Based Untargeted and Targeted Metabolomics Approaches Reveal the Entomological Origins of Honey

A comprehensive liquid chromatography-mass spectrometry (LC-MS)-based metabolomics approach was developed to discriminate honey harvested from Apis mellifera ligustica Spinola (A. mellifera) and Apis cerana cerana Fabricius (A. cerana). Based on an untargeted strategy, ultrahigh-performance liquid chromatography electrospray ionization quadrupole orbitrap high-resolution mass spectrometry (UPLC Q-Orbitrap) was combined with chemometrics techniques to screen and identify tentative markers from A. mellifera and A. cerana honey. In targeted metabolomics analysis, a sensitive method of solid-phase extraction followed by ultrahigh-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UPLC-MS/MS) was established for quantifying three markers, and the results showed that 3-amino-2-naphthoic acid and methyl indole-3-acetate could be considered markers of A. cerana honey, as they were present in higher amounts in A. cerana honey than in A. mellifera honey, whereas kynurenic acid was determined to be a marker of A. mellifera honey. This work highlights critical information for the authentication of A. cerana and A. mellifera honey.

Molecularly imprinted polymers in toxicology: a literature survey for the last 5 years

The science of toxicology dates back almost to the beginning of human history. Toxic chemicals, which are encountered in different forms, are always among the chemicals that should be investigated in criminal field, environmental application, pharmaceutic, and even industry, where many researches have been carried out studies for years. Almost all of not only drugs but also industrial dyes have toxic side and direct effects. Environmental micropollutants accumulate in the tissues of all living things, especially plants, and show short- or long-term toxic symptoms. Chemicals in forensic science can be known by detecting the effect they cause to the body with the similar mechanism. It is clear that the best tracking tool among analysis methods is molecularly printed polymer-based analytical setups. Different polymeric combinations of molecularly imprinted polymers allow further study on detection or extraction using chromatographic and spectroscopic instruments. In particular, methods used in forensic medicine can detect trace amounts of poison or biological residues on the scene. Molecularly imprinted polymers are still in their infancy and have many variables that need to be developed. In this review, we summarized how molecular imprinted polymers and toxicology intersect and what has been done about molecular imprinted polymers in toxicology by looking at the studies conducted in the last 5 years.

Aminoglycosides analysis optimization using ion pairing liquid chromatography coupled to tandem mass spectrometry and application on wastewater samples

Aminoglycosides are mostly used as veterinary antibiotics. In France, their consumption accounts for about 10% of all prescribed animal medicine. Due to their high polarity nature (log Kow < -3), they require chromatographic separation by hydrophilic interaction liquid chromatography or ion-pairing chromatography. This study presents the development of an ion pairing liquid chromatography with alkanesulfonates coupled to tandem mass spectrometry for the analysis of 10 aminoglycosides (spectinomycin, streptomycin, dihydrostreptomycin, kanamycin, apramycin, gentamicin, neomycin and sisomicin) in wastewater samples. The novelty of this method lies in the addition of the ion paring salt directly and only into the sample vial and not in the mobile phase, lowering the amount of salt added and consequently reducing signal inhibition. The optimized method was validated and showed satisfactory resolution, performances suitable with the analysis of aminoglycosides in wastewater samples, with limits of quantifications less than 10 ng/mL for most of the compounds, low matrix effects, high accuracy (85%-115% recoveries) and reproducibility (2%-12%RSD). It was then applied successfully to raw and treated wastewater samples.

Recent advances in aptamer-based sensors for aminoglycoside antibiotics detection and their applications

Aminoglycoside antibiotics (AAs) have been extensively applied in medical field and animal husbandry owing to desirable broad-spectrum antibacterial activity. Excessive AAs residues in the environment can be accumulated in human body through food chain and cause detrimental effect on human health. The establishment of highly specific, simple and sensitive detection methods for monitoring AAs residues is highly in demand. Aptasensor using aptamer as the biological recognition element is the efficient and promising sensing method for detection of AAs. In this review, we have made a summary of specific aptamers sequences against AAs. Subsequently, we provide a systematical and comprehensive overview of modern techniques in aptasensors for detection of AAs according to optical aptasensors as well as electrochemical aptasensors and further summarize their advantages and disadvantages to compare their applications. In addition, we present an overview of practical applications of aptasensors in sample detection of AAs. Moreover, the current challenges and future trends in this field are also included to reveal a promising perspective for developing novel aptasensors for AAs.

Design of green coating material of combining rigid and flexible properties for the extraction of aminoglycosides residues

Bio-based and low-cost hybrid polyvinyl alcohol (PVA) and gelatin (Gel) hydrophilic macromolecular complex coated microspheres were prepared based on one-pot process, characterized, and applied as novel sorbent materials for the purification of trace aminoglycosides from complex matrices. PVA acts as a "rigid" component in the hybrid complex to enhance its mechanical properties, while Gel's "flexible" role is to improve the swelling properties of the hybrid complex in water. It is shown that hybrid PVA/Gel-functionalized sorbents are more efficient than the respective PVA or Gel sorbents since the presence of Gel increases the material selectivity for aminoglycosides, which is due to the specific interactions occurring between the targets and amino acid residues in the hybrid materials. Under the optimum conditions, material preparation and pretreatment processes were entirely carried out in single water system without toxic organic solvent. The detection limit (LOD) of spectinomycin, kanamycin, streptomycin and dihydrostreptomycin in honey were 0.811, 0.303, 0.168, 0.045 μg⋅kg^-1 respectively. Linearity was obtained in the range of 20 to 2000 ug⋅kg^-1, relative recovery yield up to 84.1-111.7% were obtained and matrix effect of all four aminoglycosides was within 100.8-107.6%. Intra-day and inter-day precision under four spiking levels (5, 200, 500 and 1000 ug⋅kg^-1) were less than 10.9% (n=6) and 13.6% (n=3) respectively. In addition, the sorbents exhibited excellent reusability even after six recycles. This work demonstrates the potential of bio-based and low-cost hybrid polymer extraction platforms as promising bonded phase alternatives, in which eco-friendly and natural-based polymers can be used to improve the material selectivity and are conducive to the realization of "green chemistry".

Investigation into reversed-phase chromatography peptide separation systems Part IV: Characterisation of mobile phase selectivity differences

The differentiation of mobile phase compositions between sub-classes which exhibit distinct chromatographic selectivity (i.e. termed characterisation) towards a range of peptide probes with diverse functionality and hence the possibility for multi-modal retention mechanisms has been undertaken. Due to the complexity of peptide retention mechanisms in given mobile phase conditions, no attempt has been made to explain these, instead mobile phases have simply been classified into distinct groups with an aim of identifying those yielding differing selectivities for use in strategic method development roadmaps for the analysis of peptide mixtures. The selectivity differences between nine synthetic peptides (fragments of [Ile27]-Bovine GLP-2) were used to assess how fifty-one RPC mobile phase compositions of differing pH (range 1.8 - 7.8), salt types, ionic strengths, ion-pair reagents and chaotropic / kosmotropic additives affected chromatographic selectivity on a new generation C18 stationary phase (Ascentis Express C18). The mobile phase compositions consisted of commonly used and novel UV or MS compatible additives. The chemometric tool of Principal Component Analysis (PCA) was used to visualise the differences in selectivity generated between the various mobile phases evaluated. The results highlight the importance of screening numerous mobile phases of differing pH, ion-pair reagents and ionic strength in order to maximise the probability of achieving separation of all the peptides of interest within a complex mixture. PCA permitted a ranking of the relative importance of the various mobile phase parameters evaluated. The concept of using this approach was proven in the analysis of a sample of Bovine GLP-2 (1-15) containing synthesis related impurities. Mobile phases with high ionic strength were demonstrated to be crucial for the generation of symmetrical peaks. The observations made on the C18 phase were compared on three additional stationary phases (i.e. alkyl amide, fluorophenyl and biphenyl), which had previously been shown to possess large selectivity differences towards these peptides, on a limited sub-set of mobile phases. With the exception of the ion-pair reagent, similar trends were obtained for the C18, fluorophenyl and biphenyl phases intimating the applicability of these findings to the vast majority of RPC columns (i.e. neutral or weakly polar in character) which are suitable for the analysis of peptides. The conclusions were not relevant for columns with a more disparate nature (i.e. containing a high degree of positive charge).

Simultaneous determination of ten aminoglycoside antibiotics in aquatic feeds by high-performance liquid chromatography quadrupole-orbitrap mass spectrometry with pass-through cleanup

A simple and sensitive method has been established based on pass-through cleanup and high-performance liquid chromatography quadrupole-orbitrap mass spectrometry (HPLC-Q/Orbitrap MS) for the simultaneous determination of ten aminoglycosides (AGs) in aquatic feeds. The extraction solution and cleanup procedure had been optimized, and good sensitivity, accuracy, and precision were obtained. The calibration curves of AGs were linearity (R² > 0.99) in the range of 2.0 to 200 μg/L (or 5.0 to 500 μg/L). The limits of detection of AGs were between 10 and 25 μg/kg. The recoveries of AGs ranged from 74.9% to 94.3%, and the intraday and interday relative standard deviations were less than 15%. Finally, this method was successfully applied to determine ten AGs in 30 aquatic feed samples. It might be the first time to use pass-through cleanup approach combined with HPLC-Q/Orbitrap MS method for AGs determination in aquatic feed samples.

Development of carbohydrate functionalized magnetic nanoparticles for aminoglycosides magnetic solid phase extraction

Magnetic nanoparticles decorated with d-galactose and galactitol (Fe₃O₄@SiN-galactose and Fe₃O₄@SiN-galactitol) were synthesized and employed as sorbent in a magnetic solid phase extraction (MSPE) procedure prior the analysis of aminoglycosides (AGs) in honey samples by LC-MS/MS. AGs are broad spectrum antibiotics, characterized by aminosugars, widespread used in therapeutic and veterinary applications. AGs can be found in the environment and food of animal origin. Fe₃O₄@SiN-galactose and Fe₃O₄@SiN-galactitol were synthesized via copper catalyzed alkyne azide cycloaddition and the synthesis was efficiently followed by infrared spectroscopy. They were characterized by electron microscopy, thermogravimetric analysis and magnetization curves. The nature of the loading (acetonitrile:water, 50:50 v/v) and elution solution (formic acid 190 mM) were studied in order to optimize the MSPE. Quantitative difference between MSPE with Fe₃O₄@SiN-galactose and MSPE with Fe₃O₄@SiN-galactitol in terms of recovery was found. The final optimized method using Fe₃O₄@SiN-galactose and Fe₃O₄@SiN-galactitol was applied in the determination of AGs in honey. The MSPE performance of Fe₃O₄@SiN-galactitol was found to be superior to that of MSPE with Fe₃O₄@SiN-galactose. The limits of quantification were between 2 and 19 μg kg^-1 for amikacin, dihydrostreptomycin, tobramicyn and gentamycin. A good correlation between predicted and nominal values of AGs in honey was found (trueness from 84% to 109%). This MSPE procedure not only requires a minimum amount of sorbent (1 mg) and sample (0.2 g), but it can also be accomplish in a rather short time.

Determination of four main components of gentamicin in animal tissues after solid-phase extraction by high-performance liquid chromatography/tandem mass spectrometry

RATIONALE

An analytical method for gentamicin in animal tissues was developed and validated. An alkaline mobile phase with an HPH C₈ column was selected so that all the four gentamicin components were retained and eluted without using fluorinated ion-pairing reagents.

METHODS

The method is sufficiently sensitive and highly selective, using a strong cation-exchange solid-phase extraction cartridge (PCX) to clean up the samples. Different types of solid-phase extraction columns and membranes were considered to obtain a high recovery. The method was validated on spiking samples, recovery, inter- and intra-assay variation, to ensure its accuracy and precision.

RESULTS

The LOQ (S/N ≥ 10) for gentamicin in goat meat, liver, kidney and adipose tissue was 25, 50, 30 and 30 ng/g, respectively; the LOD (S/N ≥ 3) was 5, 10, 10 and 10 ng/g, respectively. The recoveries were between 88% and 106%. The method in all animal tissues was calibrated from 10 to 1000 μg/L in the matrix-assisted standard solution.

CONCLUSIONS

The novelty of this method is that the commonly used fluorinated ion-pairing reagent was not used in the mobile phase in our analysis, greatly reducing the contamination of the ESI source in negative mode. Moreover, the four gentamicin components were clearly separated via chromatographic separation.