High performance liquid chromatography for the simultaneous analysis of penicillin residues in beef and milk using ion-paired extraction and binary water–acetonitrile mixture

Design and fabrication of a competitive lateral flow assay using gold nanoparticle as capture probe for the rapid and on-site detection of penicillin antibiotic in food samples

Lateral flow assays (LFAs) are among the utmost cost-efficient, paper-based point-of-care (POC) diagnostic devices. Herein, we have reported the fabrication of a competitive LFA for on-site detection of penicillin. Various parameters such as Ab concentration for conjugation, Pen-BSA conjugate concentration, pore size of membrane, and blocking buffer were standardised for the fabrication of LFA. Different concentrations of penicillin (1 pM-1 mM) were added to the sample pad to observe the color intensity. The visual detection limit (LOD) achieved from the LFA was 10 nM for Penicillin that correlated with the LOD calculated from the 'ColorGrab' colorimeter application. Additionally, LFA showed insignificant cross reactivity with other β-lactam antibiotics and were also validated with spiked food samples such as milk, meat and egg. Hence, the fabricated LFA can be successfully utilised for the POC detection of penicillin in food samples on large scale.

The neurodevelopmental toxicity induced by combined exposure of nanoplastics and penicillin in embryonic zebrafish: The role of aging processes

As ubiquitous contaminants, nanoplastics and antibiotics are frequently co-presence and widely detected in the freshwater environment and biota, posing a high co-exposure risk to aquatic organisms and even humans. More importantly, how the aging process of nanoplastics affects the joint toxic potential of nanoplastics and antibiotics has not been explored. Here, we generated two aged polystyrene nanoplastics (PS) by UV radiation (UV-PS) and ozonation (O3-PS). Non-teratogenic concentrations of pristine PS (80 nm) and antibiotics penicillin (PNC) co-exposure synergistically suppressed the embryo heart beating and behaviors of spontaneous movement, touch response, and larval swimming behavioral response. Pristine PS and aged UV-PS, but not aged O3-PS, showed similar effects on zebrafish embryo/larval neurodevelopment. However, when co-exposure with PNC, both aged PS, but not pristine PS, showed antagonistic effects. In late-stage juvenile social behavior testing, we found that PS decreased the exploration in light/dark preference assay. The synergistic effect of aged PS with PNC was further explored, including cellular apoptosis, ROS formation, and neurotransmitter metabolite regulation. Mechanistically, aged UV-PS but not O3-PS significantly increased the adsorption rate of PNC compared to pristine PS, which may account for the toxicity difference between the two aged PS. In conclusion, our results confirmed that PS served as a carrier for PNC, and the environmental aging process changed their neurobehavioral toxicity pattern in vivo.

Supramolecular Solvent-Based Liquid Phase Microextraction Combined with Ion-Pairing Reversed-Phase HPLC for the Determination of Quats in Vegetable Samples

In this study, we used anion supramolecular solvent (SUPRAS) prepared from a mixture of an anionic surfactant, sodium dodecyl sulfate (SDS), and a cationic surfactant, tetrabutylammonium bromide (TBABr), as the extraction solvent in liquid phase microextraction (LPME) of paraquat (PQ) and diquat (DQ). The enriched PQ and DQ in the SUPRAS phase were simultaneously analyzed by ion-pairing reversed-phase high performance liquid chromatography. PQ and DQ were successfully extracted by LPME via electrostatic interaction between the positive charge of the quats and the negative charge of SUPRAS. PQ, DQ, and ethyl viologen (the internal standard) were separated within 15 min on a C18 column, with the mobile phase containing 1-dodecanesulfonic acid and triethylamine, via UV detection. The optimized conditions for the extraction of 10 mL aqueous solution are 50 μL of SUPRAS prepared from a mixture of SDS and TBABr at a mole ratio of 1:0.5, vortexed for 10 s at 1800 rpm, and centrifugation for 1 min at 3500 rpm. The obtained enrichment factors were 22 and 26 with limits of detection of 1.5 and 2.8 µg L^-1 for DQ and PQ, respectively. The precision was good with relative standard deviations less than 3.86%. The proposed method was successfully applied for the determination of PQ and DQ in vegetable samples and recoveries were found in the range of 75.0% to 106.7%.

Antibiotic residues in milk: Past, present, and future

Now-a-days, various types of antibiotics are being used worldwide in veterinary sector indiscriminately for promotion of growth and treatment of the livestock. Significant portions of antibiotics are released through milk of dairy animals unaltered and exert serious harmful effects on human health. This review evaluates and compare researches on antibiotic residues in milk in published literatures from Pubmed, CrossRef, CAB direct, DOAJ, JournalTOCs, AGRICOLA, ScientificGate, Electronic Journals Library, CAB abstracts, Global Health Databases, Global Impact Factor, Google Scholar, Park Directory of Open Access Journals, BanglaJOL and ISC E-Journals. Antibiotics residue in milk was first detected in 60s and then with an increasing trend with highest after 2,000 (188). The highest no. of works, 49 (21.87%) were accomplished in China, followed by Spain, 30 (13.39%); Germany, 11 (4.91%); and USA, 10 (4.46%). Continent-wise highest researches are published from Europe, 105 (46.88%), followed by Asia, 77 (34.38%); South America, 18 (8.04%); North America, 16 (7.14%); and Africa, 8 (3.57%). For detection, Bovine milk sample is mostly used, 193 (86.16%), followed by ovine, 19 (8.48%); and caprine, 14 (6.25%). Acetonitrile was used in maximum cases (77) for processing the samples. Chromatographic technique was the highest, 115 (51.34%) for detection. Residue of β-lactam group have been detected mostly 133 (36.54%), followed by tetracyclines, 51 (14.01%); fluoroquinolones, 49 (13.46%); sulfonamides, 46 (12.64%); and aminoglycosides, 38 (10.44%). This review observe that antibiotics residues are more common in milk samples that are being manifested in increasing researches on antibiotic detection and measures should adopt to cease this residue.

SERS investigation and high sensitive detection of carbenicillin disodium drug on the Ag substrate

The reliable and ultrasensitive detection of antibiotic drug residue is of great interest for environmental protection and human health. Herein, we propose a simple SERS strategy based on Ag nanoparticles (NPs) as substrate with the assistance of aggregation agent (MgSO₄) for the SERS investigation and the high sensitive detection of antibiotic drug carbenicillin disodium (CBDM). The density functional theory calculation was performed for the assignment and identification of Raman bands of the CBDM molecule. The results indicate that the CBDM molecule is close to the Ag NP substrate surface through the carboxyl group. The CBDM molecules on Ag NP substrate exhibit the largest SERS enhancement, when the concentration of MgSO₄ is 1 × 10^-2 mol/L and the pH value of CBDM solution is 6. By this SERS method, the limit of detection of CBDM is 0.63 × 10^-8 mol/L, which is lower than the standard of European Union for the maximum residue limit of antibiotic drug (1.2 × 10^-8 mol/L). And, a quantitative detection method of CBDM can be established. There is a good linear relationship (R² = 0.9908) in the concentration range of 1.0 × 10^-8-1.0 × 10^-3 mol/L. It proves that the proposed SERS method is a simple, rapid (within 6 min), reliable and highly sensitive scheme with a good reproducibility for the detection of CBDM. And, the proposed SERS strategy can also be applied for the high sensitive detection and identification of other antibiotic drug (penicillin).

Influence of High pH on the Organization of Acetonitrile at the Silica/Water Interface Studied by Sum Frequency Generation Spectroscopy

The acetonitrile-water mixture is one of the most commonly used solvents in hydrophilic interaction chromatography, which contains silica as the solid phase. As such, the silica/acetonitrile-water interface plays a large role in the separation of compounds. Varying the pH is one way to influence retention times, particularly of ionizable solutes, yet the influence of high pH is often unpredictable. To determine how the structure of this interface changes with pH, we utilized the surface specific technique sum frequency generation (SFG). Previous SFG studies at neutral pH have suggested the existence of acetonitrile bilayers at the aqueous silica interface even at low acetonitrile mole fractions. Here we find that the SFG signal from 2900 to 3040 cm^-1 at the silica/acetonitrile-water interface increased as we adjusted the aqueous pH from near neutral to high values. This increase in signal was attributed to a greater amount of aligned water which is consistent with an increase in silica surface charge at high pH. In contrast, complementary measurements of the silica/acetonitrile-deuterium oxide interface revealed that the acetonitrile methyl mode nearly vanished as the aqueous pH was increased. This loss of methyl mode signal is indicative of a decrease in the number density of acetonitrile molecules at the interface, as orientation analysis indicates no significant change in the net orientation of the outer leaflet of the acetonitrile bilayer over the pH range studied.

High sensitive detection of penicillin G residues in milk by surface-enhanced Raman scattering

The antibiotic residue in animal source foods (milk, meat, etc.) is threatening people's health due to its abusing in livestock breeding more and more seriously. In this study, a simple and sensitive SERS method coupled with a two-step pretreatment process of sample was proposed for the residue detection of penicillin G (PENG) in real milk sample. It can be found that the two-step pretreatment process of sample is an essential procedure for the successful detection of PENG residue in milk, which can effectively avoid interference from other components in the sample and achieve the trace-level detection of PENG residue by SERS. Under the optimal test conditions, the limit of detection of PENG residue is 2.54×10^-9mol/L (equal to 0.85μg/kg), which is lower than the standard of the European Union (4μg/kg). And, there is a good linear relationship (R²=0.9902) in the concentration range of 1.0×10^-8~1.0×10^-3mol/L. By this method, the recovery of PENG residue ranges from 76% to 97% with relative standard deviation between 4.8% and 2.1%. The proposed SERS method can be effectively applied for determination of PENG residue in milk.

Determination of nucleosides and nucleotides in baby foods by hydrophilic interaction chromatography coupled to tandem mass spectrometry in the presence of hydrophilic ion-pairing reagents

In this work we propose a rapid and efficient method for the joint determination of nucleosides and nucleotides in dairy and non-dairy baby foods based on hydrophilic interaction chromatography coupled to tandem mass spectrometry in the presence of diethylammonium (DEA) as a hydrophilic ion-pairing reagent (IP-HILIC-MS/MS). Sample treatment of the baby food included dilution with water and centrifugal ultrafiltration (CUF) with an additional washing step that notably improved the global performance of the process. Later dilution of the extract with acetonitrile allowed adequate separation in the HILIC system. With the proposed treatment, we obtained extraction recoveries higher than 80% and, additionally, no matrix effects were observed. The CUF-IP-HILIC-MS/MS method was validated according to the 2002/657/EC decision and was used for the quantification of nucleotides and nucleosides in sixteen samples of commercial baby foods.

Circular dichroism spectroscopy: An efficient approach for the quantitation of ampicillin in presence of cloxacillin

Ampicillin exhibited a negative and a positive cotton effects on the circular dichroism (CD) spectra in the wavelength range of 200-280nm. Cloxacillin showed a positive cotton band peaking at 228nm. Three sensitive, precise and accurate CD spectroscopic methods have been developed for the determination of ampicillin and cloxacillin. Method A was used for the determination of ampicillin in presence of cloxacillin by measuring ellipticity at 206nm. Method B and C were employed to determine ampicillin and cloxacillin based on evaluation of ellipticity at 233nm and 228nm, respectively. Methods A, B and C showed linearity in the concentration range of 10-40μgmL(-1), 5-40μgmL(-1) ampicillin and 10-80μgmL(-1) cloxacillin, respectively. The method A was successfully applied to the determination of ampicillin in commercial dosage forms containing equivalent amount of cloxacillin.

Analysis of Six β-Lactam Residues in Milk and Egg by Micellar Electrokinetic Chromatography with Large-Volume Sample Stacking and Polarity Switching

A new micellar electrokinetic chromatography method with large-volume sample stacking and polarity switching was developed to analyze amoxicllin, cephalexin, oxacillin, penicillin G, cefazolin, and cefoperazone in milk and egg. The important parameters influencing separation and enrichment factors were optimized. The optimized running buffer consisted of 10 mM phosphate and 22 mM SDS at pH 6.7. The sample size was 1.47 kPa × 690 s, the reverse voltage was 20 kV, and the electric current recovery was 95%. Under these optimum conditions, the enrichment factors of six β-lactams were 193-601. Their LODs were <0.26 ng/g, and LOQs were all 2 ng/g, which was only 1/50-1/2 of the maximum residual limits demanded by U.S. and Japanese regulations. The intraday and interday RSDs of method were lower than 3.70 and 3.91%, respectively. The method can be applied to determine these six antibiotic residues in egg and milk.