Bovine Urine Samples Research Articles

Synthesis and application of magnetic graphene oxide covalent organic framework composite for extraction of anabolic androgenic steroids and β-agonists in animal urine and tissue samples

In this work, a magnetic graphene oxide covalent organic framework composite was synthesized and utilized as an effective sorbent for magnetic solid phase extraction. A comprehensive investigation was conducted to optimize the extraction conditions, including sample pH, sample volume, adsorbent amount, adsorption time, choice of elution solution, elution volume, elution time, and ionic strength. Subsequently, the developed extraction method was combined with liquid chromatography-tandem mass spectrometry for the detection of 7 anabolic androgenic steroids and 4 β-agonists. Under the optimized condition, the limits of detection for the 7 anabolic androgenic steroids and 4 β-agonists ranged from 0.5 to 2 ng L−1, with relative standard deviations varying from 4.18 % to 12.4 % at a concentration of 0.025 μg L−1. Calibration curves were established using the peak area of analytes at concentrations spanning 5–500 ng L−1, resulting in correlation coefficients within the range of 0.9949–0.9989. The enrichment factors achieved through magnetic solid phase extraction were found to be 91.4–97.3. The proposed method was successfully applied for the determination of target analytes in hog urine, bovine urine, beef, mutton, pig liver and pork powder samples. Ractopamine and clenbuterol were identified in the pork powder (quality control sample) at concentrations of 21.0 μg kg−1 and 42.6 μg kg−1, respectively. The proposed method is a sensitive, reliable, and convenient analytical method for anabolic androgenic steroids and β-agonists monitoring in animal urine and tissues.

On-site monitoring of nandrolone in cattle farming samples by portable atmospheric pressure chemical ionization mass spectrometry with ambient sampling

Nandrolone (NT) is a type of androgen anabolic steroid that is often illegally used in cattle farming, leading to unpredictable harm to human health via the food chain. In this study, a rapid detection method for NT in the samples of cattle farming was established using a portable mass spectrometer. The instrument parameters were optimized, including a thermal desorption temperature of 220 °C, a pump speed of 30 %, an APCI ionization voltage of 3900 v, and an injection volume of 6 μL. The samples of bovine urine, feed, sewage, and tissue were selected, and extracted using a solution of methanol:acetonitrile (1:1, v/v), followed by spiking a NT standard solution (1000 ng·mL−1) and ionization through the APCI ion source for detection. The results showed that NT could not be detected in beef and feed due to the complexity of the matrix, while clear signals of NT ions were observed in bovine urine and sewage samples, with LODs of 1000 and 100 ng·mL−1, respectively. Furthermore, quantitative analysis was attempted, and a good linear relationship (R2 = 0.9952) was observed for NT in sewage within the range of 100 to 1000 ng·mL−1. At spiked levels of 100, 500, 1000 and 2000 ng mL−1, the recovery rates ranged from 74.3 % to 92.8 %, with a relative standard deviation (n = 6) of less than 15 %. In conclusion, this detection method offers the advantages of simplicity, rapidity, strong timeliness, and specificity, making it suitable for on-site detection. It can be used for qualitative screening of nandrolone in bovine urine and quantitative analysis of nandrolone in sewage.

Optimization, validation, and application of a liquid chromatography-tandem mass spectrometry method for the determination of 47 banned drug and related chemical residues in livestock urine using graphitized carboxyl multi-walled carbon nanotubes-based QuEChERS extraction

The establishment of an efficient method for the analysis of drug residues in animal urine facilitates the real-time monitoring of drugs used in the production of animal-derived food. A modified QuEChERS extraction–liquid chromatography-tandem mass spectrometry (LC–MS/MS) method was established for the determination of 47 banned drug and related chemical residues in livestock urine. The sample was extracted with acetonitrile by converting the acid-base environment. The sample cleanup effects of seven solid phase extraction cartridges and two EMR-Lipid products were compared, and three materials, including graphitized carboxyl multi-walled carbon nanotubes (MWCNTs), PSA, and C18, were selected as QuEChERS adsorbents from 24 materials. All analytes showed good linearity, with correlation coefficients (R2) greater than 0.9936. Low limits of quantification could be obtained, ranging from 0.2 to 5.5 ng/mL. The average recoveries at low, medium, and high spiked levels were in the range of 70.8–114.9 %, with intra-day precision ranging from 2.4 % to 11.2 % and inter-day precision ranging from 4.5 % to 16.1 %. Swine urine and bovine urine samples collected from different farms were effectively analyzed using the developed method, and metronidazole was detected in three swine urine samples.

Multi-class/residue method for determination of veterinary drug residues, mycotoxins and pesticide in urine using LC-MS/MS technique

BackgroundVeterinary drugs are widely used in animals to prevent diseases and are a complex set of drugs with very different chemical properties. Multiclass and multi-residue methods for simultaneous detection of residues from veterinary drugs and contaminants in urine are very rare or non-existent. Therefore, the aim of this study was to develop and validate a sensitive and reliable quantitative LC-MS/MS method for simultaneous determination of a wide range of veterinary drug and pesticide residues and mycotoxins in bovine urine. This involved 42 veterinary drug residues (4 thyreostats, 6 anabolic hormones, 2 lactones, 10 beta agonists, 15 antibiotics, 5 sulphonamides), 28 pesticides and 2 mycotoxins. Stable isotopically labelled internal standards were used to facilitate effective quantification of the analytes. Analysis was performed in both positive and negative ionization modes with multiple reaction monitoring transitions over a period of 12 min.ResultsThe parameters validated included linearity, limit of detection (LOD), limit of quantification (LOQ), detection capability (CCβ), decision limit (CCα), stability, accuracy and precision. The process followed guidelines of the regulation 2021/808/EC. The calibration curves were linear with coefficient of correlation (R2) from 0.991 to 0.999. The LODs were from 0.01 to 2.71 µg/L, while the LOQs were from 0.05 to 7.52 µg/L. The CCα and CCβ were in range 0.05–12.11 µg/L and 0.08–15.16 µg/L. In addition, the average recoveries of the spiked urine samples were from 71.0 to 117.0% and coefficient of variation (CV) < 21.38% (intraday and interday).ConclusionA new isotopic LC-MS/MS method has been developed, validated and applied for identification and quantification of 72 residues of veterinary drugs and pesticides and other contaminants such as mycotoxins in bovine urine. The most appropriated sample preparation procedures involved sodium acetate buffer, enzymatic hydrolysis using β-glucuronidase and cleanup solid phase extraction with OASIS SPE cartridges. The parameters were satisfactorily validated fulfilling requirements under Regulation 2021/808/EC. Consequently, the method could be used in routine analysis of bovine urine samples for simultaneous detection of veterinary drug and pesticide residues as well as contaminants such as mycotoxins.

Creatinine recovery from bovine urine under the effect of different times and temperatures of storage.

Creatinine is a urinary marker used widely in ruminant's experimental trials. However, despite its great importance no data were found in the literature about the best way to store bovine urine samples. In the sheep urine, was observed an increase in the urinary concentration of creatinine when it was stored acidified (pH 2.5 to 3.5) at a temperature of 28 to 39 °C for 150 days of storage. Nevertheless, urine should be stored acidified (pH below 3) to avoid purine derivative degradation, So, aimed to evaluate creatinine recovery in bovine urine as a function of storage time and temperature. A total of 25 animals' urine (10 Nellore cattle and 15 Holstein cattle) were collected. The urine (40 mL) was diluted in 160 mL of distilled water and its pH was corrected to a value lower than 3 using sulfuric acid drops. A sample of the diluted urine was analyzed to obtain the creatinine concentration reference value on the collection day. The remaining urine was fractionated and preserved at room temperature, cooled (4 °C) or frozen (-20 °C and -40 °C). In the urine of five Holstein cattle was added creatine solutions (20, 40 and 60 mg/dL) to evaluate the creatine to creatinine conservation. These urine samples were analyzed on different days after collection (1, 3, 7, 15, 30 and 45 days). The urine without any added creatine was analyzed on Days 1, 3, 7, 10, 15, 30, 45, 60, 90, 120, and 150 of storage. The addition of creatine in the urine caused an increase in the creatinine concentration (P < 0.05) after 30 days of storage at room temperature and under refrigeration (4 °C). In frozen samples, there was no change in creatinine concentration (P > 0.05). However, creatinine recovery was constant (P > 0.05) until day 15 of storage, regardless of the temperature used, when creatine was not added. After 30 days of storage, an effect of time and/or temperature was observed on creatinine recovery (P < 0.05). Urine samples can be stored at any temperature for up to 15 days after collection to estimate the creatinine concentration. Samples that need storage times longer than 15 days should be frozen (at -20 °C and -40 °C) to avoid creatinine concentration variation.

Sensitive acid phosphatase assay based on light-activated specific oxidase mimic activity

Acid phosphatase (ACP) is a key marker in the diagnosis of many diseases. However, exploiting a simple and sensitive sensor for the real-time quantitative analysis of ACP is still challenging. Herein, we attempted to develop a sensitive colorimetric sensing strategy for the detection of ACP based on light-activated oxidase mimic property of carbon dots (CDs). The synthesized CDs were proved to be capable of intrinsic light-activated oxidase mimic activity, which could generate reactive oxygen species to oxidize chromogenic substrate under ultraviolet light stimulation. Interestingly, this light-activated oxidase mimic behavior would be effectively suppressed by the antioxidant ascorbic acid (AA), a product from the hydrolysis of 2-phospho-L-ascorbic acid trisodium (AAP) mediated by ACP. Based on the above property, a facile and sensitive colorimetric sensing method for ACP was developed. Under the optimal conditions, the linear range for ACP 0.1–5.5 U/L, and the detection limit was 0.056 U/L. Compared with conventional nanozyme based ACP assay systems, the catalytic activity of light-activated nanozyme could be conveniently regulated by switching the light on and off, which made it easier to precisely control the extent of the reaction and ensured the accuracy of the assay. In addition, the proposed sensing system would be readout directly by the naked eye or smartphone-based RGB analysis system, and have been successfully applied to analyze diluted in diluted fetal bovine serum and urine samples spiked with ACP. All these results indicated that this approach holds good promise for future applications in clinical analysis and point-of-care (POC) biosensor platforms.

The effects of data balancing approaches: A case study

Imbalanced datasets affect the performance of machine learning algorithms adversely. To cope with this problem, several resampling methods have been developed recently. In this article, we present a case study approach for investigating the effects of data balancing approaches. The case study concerns the discrimination between growth hormone treated and non-treated animals using Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) data. Our LC-HRMS dataset contains 1241 bovine urine samples, of which only 65 specimens were from animal studies and guaranteed to contain growth-stimulating hormones while the rest has been reported to be untreated, making it a ∼5% imbalanced dataset. In this research, classification algorithms, combined with resampling strategies and dimensionality reduction methods, were investigated to find a prediction model to correctly identify the samples of treated animals. Furthermore, to cope with a large number of missing data points in the given dataset, a replacement with random low values strategy was applied. Our results showed that the replacement method was effective, and LogisticRegression combined with the oversampling algorithms SMOTE or ADASYN, GaussianProcessClassifier with the oversampling algorithm SMOTE, and LinearDiscriminantAnalysis were the best performing models after log transformation of the dataset was followed by Recursive Feature Elimination.

Gold Nanoparticles‐electrochemically Reduced Graphene Oxide/Poly(indole‐5‐carboxylic acid) Nanocomposite for Electrochemical Non‐enzymatic Sensing of Hydrogen Peroxide

AbstractHerein, co‐electrodeposition of AuNPs and ERGO onto GCE was conducted to prepare the modified electrode, GCE/AuNPs‐ERGO. The poly(indole‐5‐carboxylic acid) (P(In‐5‐COOH) was then coated onto the GCE/AuNPs‐ERGO with the help of electropolymerization. FT‐IR, FE‐SEM and EDX, and XRD techniques were employed to characterize the prepared nanocomposite. The nanocomposite modified electrode (GCE/AuNPs‐ERGO/P(In‐5‐COOH)) was examined for the electrochemical reduction of H2O2 using chronoamperometry. A high reduction current for H2O2 was observed due to the synergistic effect between AuNPs‐ERGO and P(In‐5‐COOH). The proposed sensor demonstrated a wide linear range of 0.025–750 μmol L−1, with a LOD of 0.008 μmol L−1 at −0.4 V. Furthermore, the developed sensor was applied for the detection of H2O2 in fetal bovine serum and urine samples.

Cryogel Monoliths for Analyte Enrichment by Capture and Release

A platform based on cryogel monoliths in small capillaries, which allows very strong enrichment of an analyte through a capture and release process, is described. For their preparation, a photoreactive copolymer solution containing capture molecules of interest is filled into a capillary, frozen in, and then photochemically transformed into cryogel monoliths through C,H-insertion cross-linking reactions. As a test example, the platform is used for the preconcentration of dopamine from bovine serum albumin and urine samples through capture and release processes. During capture from a large volume and release into a smaller volume, the platform shows recovery rates up to 97% and allows up to a roughly 630-fold enrichment of the concentration of the analyte. The presented platform could be used as a disposable device for the purification and enrichment of a variety of cis-diol-containing samples.

Discrimination between the exogenous and endogenous origin of thiouracil in farm animals, the final chapter?

ABSTRACT Thiouracil (2-thiouracil) is a thyreostatic compound that can be used as an illegal growth promoter. In bovine, porcine and other farm animals, low concentrations of thiouracil are detected in urine. There is much debate on which concentrations can be considered to originate from feed (‘natural’) and which concentrations are caused by the illegal administration of thiouracil for growth-promoting purposes. Currently, a threshold value of 10 µg/L in urine is applied. The threshold value is based on epidemiological data. Data on thiouracil from animals treated with thiouracil is scarce. We conducted a study whereby animals were fed with rapeseed, rapeseed with thiouracil, or regular feed with thiouracil (low and high concentration). It was determined that administration of thiouracil leads to concentrations higher than the current 10 µg/L threshold of thiouracil and its metabolites in urine during treatment. Animals fed with rapeseed showed higher thiouracil concentrations than the control group, mostly above 10 µg/L and in some cases above 30 µg/L. In the discovery study, several biomarkers for thiouracil treatment were tentatively identified and confirmed with reference standards. One metabolite was identified as indicative for thiouracil abuse, namely 6-methyl-thiouracil. Another metabolite, 4-thiouracil, was indicative for endogenous formation and did not increase during 2-thiouracil treatment. 6-Methyl-thiouracil was not found in urine samples from the Dutch routine control programmes that contained (endogenous) 2-thiouracil above the threshold value. However, 4-thiouracil was found at high concentrations in the same samples when 2-thiouracil was present. This study’s overall conclusion is that the threshold value for thiouracil in bovine urine samples should be set at 10 µg/L and for porcine urine samples at 30 µg/L. Also, confirmation of 6-methyl-thiouracil and 4-thiouracil should be used as indicators for exogenous or endogenous origin in routine control monitoring programmes.

Revealing the effect of multidimensional ZnO@CNTs/RGO composite for enhanced electrochemical detection of flufenamic acid

Rational design of different heteroarchitecture-based ultrasonic approaches offer great opportunities to improve the electrocatalytic properties in electrochemical reaction. Especially, zinc oxide (ZnO)-based carbon architecture has gained tremendous interest due its fascinating properties. Herein, we have synthesized flower-like ZnO superstructures on multiwalled carbon nanotubes (CNTs)/reduced graphene oxide (RGO) composite using an ultrasonic bath (100 W at 50 kHz). The structuro-chemical and crystalline properties of ZnO@CNTs/RGO composite are analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) analysis, and Raman spectroscopic analysis. Also, the as-synthesized ZnO@CNTs/RGO composite has been successfully applied towards the electrochemical detection of the nonsteroidal anti-inflammatory drug, flufenamic acid (FFA). As expected, ZnO@CNTs/RGO composite modified glassy carbon electrode (GCE) exhibits excellent electrocatalytic performance towards FFA detection, when compared to other modified and un-modified GCEs. The positive synergistic effect between ZnO, CNTs and RGO in the composite is highlighted by the advanced electrochemical sensing performance of the fabricated GCE which can be ascertained to more number of active sites and rapid electron transport. The proposed sensor establishes two response ranges with trace level detection limit and higher sensitivity towards FFA sensing. The feasibility of the sensor is also validated by its application towards the determination of FFA in bovine serum albumin and urine samples which offers satisfying recovery range. Thus the manipulation of the hierarchical architecture of ZnO together with the electronic conductivities of CNTs and RGO tailor the formation of a nanocomposite which can be utilized for real analysis of pollutants.

Leptospira transport medium (LTM): A practical tool for leptospires isolation

The isolation of Leptospira is challenging, since the bacteria of this genus are susceptible to adverse environmental conditions and may not remain viable for extend periods in urine samples. This study attempted to develop and evaluate a simple and practical method to isolate leptospires from bovine urine samples. A culture medium for sample transport, named Leptospira Transport Medium (LTM), was described and validated using reference serovars of Leptospira spp. in addition to autochthonous strains isolated in Brazil. We evaluated LTM in the field, by collecting 215 urine samples from slaughtered cattle and immediately seeding them in LTM and Fletcher's medium, used as control. The cultures were sent to a laboratory within 10 days for further processing. Moreover, 16S PCR was also performed on the urine samples directly to detect Leptospira DNA. Using LTM enabled 52 isolates (24.2%) to be obtained in pure culture, and contamination was only observed in 15/215 samples (7.0%). Regarding the samples in Fletcher's medium, 10 (4.6%) isolates were obtained. With 16S PCR performed in the urine samples, 31 samples (14.4%) were determined to be positive. LTM was developed and used in a simple and practical way and can significantly improve the isolation of leptospires from urine samples, as well as being highly useful in remote areas, not only in Brazil but also in other countries where few easily accessible laboratories are available. Furthermore, LTM can be prepared by laboratories and provided to veterinarians and technicians for urine collection in the field.

Comparison of Real-Time PCR, Bacteriologic Culture and Fluorescent Antibody Test for the Detection of Leptospira borgpetersenii in Urine of Naturally Infected Cattle.

Cattle are susceptible to infection with multiple serovars of pathogenic leptospires, resulting in abortion, stillbirth, premature birth, reproductive failure and milk drop syndrome. Cattle also act as a reservoir host for L. borgpetersenii serovar Hardjo which is excreted from renal tubules via urine into the environment where it persists in suitable moist conditions. Our previous work demonstrated that 7% of urine samples from beef cattle were positive for L. borgpetersenii serovar Hardjo by culture and/or the fluorescent antibody test (FAT). In this study, a real-time PCR (rtPCR) assay was applied to determine the relative performance of rtPCR based detection of L. borgpetersenii serovar Hardjo compared to previously reported culture and FAT techniques. Of 42 bovine urine samples positive for leptospires by culture and/or FAT, 60% (25/42) were positive by rtPCR. Of 22 culture-positive samples, 91% (20/22) were rtPCR-positive. Of 32 FAT-positive samples, 50% (16/32) were rtPCR-positive. For 10 samples that were culture-positive but FAT-negative, 90% (9/10) were rtPCR-positive. For 20 samples that were FAT-positive but culture-negative, 25% (5/20) were rtPCR-positive. Collectively, these results indicate that no single assay is optimal, and the use of more than one assay to detect leptospires in urine from naturally infected cattle is recommended.

Nano Green Voltammetric Determination of Imidocarb Dipropionate and Its Residues in Bovine Meat, Milk and Urine Samples

Imidocarb dipropionate (IMD) is an antimicrobial agent that is widely used in veterinary medicine for treatment of many diseases especially anaplasma marginale in cattle. This may lead to the retention of its residues in edible bovine tissues, milk and urine samples. Thus the quick determination of minor concentrations of IMD is of great interest to ensure food safety. A novel electrochemical sensor was introduced for the sensitive, fast and selective determination of IMD in drug substance and commercial product, furthermore its application to determine IMD residues in bovine meat, milk and urine samples. The prepared nanoparticles sensor was based on a multiwalled carbon nanotube composite modified with gold nanoparticles GNPs/MWCNT. The linear response obtained for IMD using the GNP/MWCNT was found to be over the range of 0.20–3.6 n mol l−1 with a good linearity and high correlation (0.9999). The limits of detection and quantification were found to be 36 p mol l−1 and 109 p mol l−1 respectively. The developed method was simple, rapid, economic, and challenging to green chemistry. The high sensitivity, good reproducibility, and wide linear range mark the modified electrode suitable for determination of the residues in bovine meat and milk as real samples with excellent recoveries.

Quantification and Stereochemical Composition of R-(-) and S-(+)-Clenbuterol Enantiomers in Bovine Urine by Liquid Chromatography-Tandem Mass Spectrometry.

Clenbuterol (4-amino-α-[(tert-butylamino)methyl]-3,5-dichlorobenzylalcohol) is a β2-adrenergic agonist. The consumption of meat contaminated with clenbuterol can lead to increased heart rate, blood pressure, anxiety, palpitations and skeletal muscle tremors. Several analytical methods have been developed to identify and quantify clenbuterol in different biological matrices. In this report, we have developed a specific and sensitive analytical method for quantifying clenbuterol and performed an in-depth enantiomeric analysis in bovine urine. The method was evaluated in accordance with international guidelines, and we used an isotopically labeled analog as an internal standard. The extraction efficiency for clenbuterol in bovine urine was > 98%, the limit of detection was 0.05ng/mL and the limit of quantification was 0.10ng/mL. Our assay showed high specificity, no carryover was observed and the assay was linear in the range 0.10-8.0ng/mL. Fifteen bovine urine samples were analyzed (containing clenbuterol), and an enantiomeric analysis was performed. The clenbuterol concentration range was 0.10-10.56ng/mL across these samples. The levorotatory enantiomer was detected at greater concentrations than the dextrorotatory enantiomer, the ratio being 1.7±0.6 (n=15), and a statistical difference was observed (P<0.05) using the Wilcoxon test.

Phthalate Metabolites, Hydroxy-Polycyclic Aromatic Hydrocarbons, and Bisphenol Analogues in Bovine Urine Collected from China, India, and the United States.

Human exposure to endocrine-disrupting chemicals (EDCs) has aroused considerable public concern over the last three decades. Nevertheless, little is known with regard to the exposure of EDCs in farm animals. In this study, concentrations of 22 phthalate metabolites (PhMs), 15 hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs), and 8 bisphenols (BPs) were determined in 183 bovine urine samples collected from China, India, and the United States. The median concentrations of urinary PhMs, OH-PAHs, and BPs in bovines, collectively, were 66, 4.6, and 16 ng/mL, respectively. Mono-n-butyl phthalate (mBP; median, 14 ng/mL) and ∑4DEHP (four secondary metabolites of di(2-ethylhexyl) phthalate; 13 ng/mL) were the dominant PhMs; hydroxy-fluorene (OH-Fluo; 1.2 ng/mL) and -phenanthrene (OH-Phen; 1 ng/mL) were the dominant OH-PAHs; and 4,4'-di-hydroxydiphenylmethane (BPF; 10 ng/mL) and 2,2-bis(4-hydroxyphenyl) propane (BPA; 6.7 ng/mL) were the dominant BPs. Bovine urine samples from India and China contained the highest concentrations of PhMs and OH-PAHs, whereas those from India and the United States contained the highest concentrations of BPs. PhM and OH-PAH concentrations were significantly higher in the urine of bulls than those of cows; no such difference was found for BPs. Our findings establish baseline exposure information about three classes of EDCs in domestic farm animals.

A glassy carbon electrode modified with silver nanoparticles and functionalized multi-walled carbon nanotubes for voltammetric determination of the illicit growth promoter dienestrol in animal urine.

An electroanalytical method for determining dienestrol (DNL) in bovine urine samples is described. A glassy carbon electrode (GCE) modified with silver nanoparticles and functionalized multi-walled carbon nanotubes was used as working sensor. The modified GCE displays substantial analytical improvements including an amplified signal, fast electron transfer kinetics, and resistance to fouling. The irreversible oxidation signal of DNL is pH-dependent. Best reactivity is found at pH3.0, where a typical anodic peak is recorded at 0.8V (vs. Ag/AgCl). Square-wave voltammetry revealed a 8.4nM detection limit (1.9μgL-1), good repeatability and reproducibility (RSDs <5.0%), and good accuracy (93.2-99.4% recovery from spiked samples). The modified electrode is highly stable even in the presence of ions (Na+ and K+), urea and uric acid. The electrochemical sensor fulfills all requisites to be used as forensic device in surveillance of illegal livestock practices. Graphical abstract Schematic presentation of the construction of a glassy carbon electrode modified with silver nanoparticles and functionalized multi-walled carbon nanotubes. This sensor exhibited a remarkable performance for voltammetric detection of the illicit growth promoter dienestrol in animal urine.

Ternary Emission of a Blue-, Green-, and Red-Based Molecular Imprinting Fluorescence Sensor for the Multiplexed and Visual Detection of Bovine Hemoglobin.

A novel ternary-emission fluorescence sensor was proposed by post-imprinting mixing blue-/green-/red-emission bovine hemoglobin (BHb) imprinted polymers (b-MIPs, g-MIPs, and r-MIPs) at a proper ratio and realized the multiplexed and visual detection of BHb. The three MIPs were individually embedded with blue-emission 7-hydroxycoumarin, green-emission CdTe quantum dots (QDs), and red-emission CdTe/ZnS QDs. Upon interaction with BHb within 8 min, the fluorescence of CdTe and CdTe/ZnS QDs were simultaneously turned off, whereas the 7-hydroxycoumarin turned on the fluorescence intensity. Thereupon, the ratiometric fluorescence intensity of the ternary emission linearly varied within 0.025-3 μM BHb, accompanying the profuse fluorescence color evolution from yellowish green to yellow to salmon to plum to purple to finally blue. In comparison with the dual- or single-emission sensor, the ternary-emission fluorescence MIPs sensor provided a wider color variation covering the green-red-blue window for accurate naked-eye determination of BHb, as well as a lower detection limit down to 7.8 nM and a higher imprinting factor of 15.2. Moreover, the satisfactory recoveries of 99.25-111.7% in determining the spiked BHb in bovine urine samples, as well as the optical stability and post-imprinting construction convenience, indicated that the developed tricolor-emission fluorescence MIPs sensor provided an ideal alternative for rapid, sensitive, and visual determination of proteins in complicated samples.

Collision cross section (CCS) as a complementary parameter to characterize human and veterinary drugs

In the context of human and veterinary drugs identification, ion mobility spectrometry (IMS) in combination with mass spectrometry (MS) may provide a relevant complementary piece of information to mass-to-charge ratio (m/z), the so-called collision-cross-section (CCS). Up to now, however, the application of CCS as identification parameter has not been fully investigated due to the reduced number of these drugs that have being characterized in terms of CCS. This work proposes a CCS database for 92 human and veterinary drugs, including eighteen benzimidazoles, eleven 5-nitroimidazoles, eleven aminoglycosides, nineteen quinolones, eighteen β-lactams, ten sulfonamides and five tetracyclines. Among them, 37 drugs have been characterized in terms of CCS for the first time. The CCS values of the other 55 compounds have been compared with those from a recently published database in order to evaluate inter-laboratory reproducibility, which is crucial for the implementation of the CCS as identification parameter. CCS values were measured by traveling wave ion mobility spectrometry (TWIMS) under positive ionization conditions. Nitrogen was used as drift gas in the ion mobility cell. The proposed database covers 173 ions including [M+H]+ and [M+Na]+ species. High correlation between m/z and CCS has been observed for [M+H]+ (R2 = 0.9518, n = 91) and [M+Na]+ (R2 = 0.9135, n = 82) ions. As expected, CCS values for sodium adducts are generally greater than for protonated molecules because they exhibit higher molecular weight. However, sodium adducts of aminoglycosides, β-lactams, and of several quinolones and benzimidazoles, were characterized as more compact ions than their related protonated molecule. In addition, this work describes the fragmentation pattern observed for the studied molecules. For the first time, the main fragment ions for most of the compounds have also been characterized in terms of CCS, involving a total of 238 ions. As proof of concept, for the application of this database to biological matrices, eleven veterinary drugs in bovine urine samples were characterized in terms of CCS, showing that this parameter was not influenced by the matrix.

Determination of Ciprofloxacin, Enrofloxacin, and Marbofloxacin in Bovine Urine, Serum, and Milk by Microextraction by a Packed Sorbent Coupled to Ultra-High Performance Liquid Chromatography

This article reports new, easy, and rapid microextraction by packed sorbent (MEPS)–ultra high performance liquid chromatography with photodiode array detection for the simultaneous determination in bovine urine, serum, and milk of three antibiotics belonging to the class of the fluoroquinolones, namely ciprofloxacin, enrofloxacin, and marbofloxacin, approved for veterinary and human use (ciprofloxacin). The chromatographic separation of the analytes and all aspects influencing the MEPS performance were optimized for the extraction from the considered biological samples. The optimized procedure required simple sample pretreatment, a short (<8 min) isocratic elution, and provided sufficient sensitivity for the determination of the analytes at trace levels in compliance with current legislation. Limits of quantitation were in the range from 0.002 (ciprofloxacin, urine) to 0.048 μg/mL (enrofloxacin, milk). Recoveries from 79% (enrofloxacin, milk) to 88% (ciprofloxacin, urine/serum) were obtained on spiked samples. The within-day (n = 6) and between-day (n = 6 over 3 days) relative standard deviation percentages in bovine urine, serum, and milk samples ranged from 2.2 (ciprofloxacin, urine) to 2.5 (enrofloxacin, serum) and from 3.1 (ciprofloxacin, urine) to 3.7 (enrofloxacin, milk), respectively, and were not concentration dependent. To the best of our knowledge, this is the first study describing a fast and simple method for the determination of fluoroquinolones in bovine biological samples.