Study on Pretreatment during Simultaneous Determination of Sulfonamides and Chloramphenicols in Honey

[ Objective] This study was conducted to establish a new UPLC-MS method for simultaneous detection of sulfonanfides and chloramphenicols in honey. [ Method] In this experiment, 0.2% formic acid-acetonitrile was used as an extractant to simultaneously extract chloramphenicoJs and sulfonamides from drugs. The extract was then loaded and extracted with an efficient separation column Oasis PRIME HLB. After nitrogen blow-concentration and dissolution with mobile phase, the extract was loaded on UPLC and detected by MS. [ Resultl There was a good linear relation in the range of 0. 1 - 10 ng/ml for chloramphenicols, with a correlation coefficient of 0.991, while sulfonamides had a good linear relation in the range of 0.5 - 50 ng/ml. The lowest detection limit of chloramphenicols and sulfonamides were 0. 1 and 0.5 μg/kg, respectively. The recoveries were in the range of 82.50% - 101.2%, with RSD values in the range of 3.2% -4.0%. [ Conclusion] This method is simple and fast with low detection limit, high recovery and good reproducibility, and could be used for simultaneous detection of re- sidual chloramphenicols and sulfonamides in honey. Key words UHPLC-MS; Sulfonamides ; Chloramphenicols ; Honey

Clinical Observation of Chuanbai Antipruritic Lotion"Water Film"Wet Compress Combined with Chloramphenicol Prednisone Liniment in the Treatment of Acute Eczema

[Objectives]To observe and analyze the clinical efficacy and possible mechanism of Chuanbai antipruritic lotion"water film"wet compress combined with chloramphenicol prednisone liniment in the treatment of acute eczema.[Methods]A total of 76 acute eczema cases admitted to Shiyan Taihe Hospital from January 2022 to March 2023 were divided into Western medicine treatment group and integrated traditional Chinese and Western medicine group.In the Western medicine treatment group,chloramphenicol and prednisone liniment was applied to the skin lesions and oral administration of cetirizine hydrochloride.The course of treatment in both groups was 2 weeks(w).The levels of interferon-γ(IFN-γ),interleukin-4(IL-4)and the ratio of IFN-γ/IL-4 in the peripheral blood of patients before and 2 weeks after treatment,as well as serum immunoglobulin E(IgE),anti-IgE antibody and histamine(HA)level,and with skin lesions disappearing time,skin oil,transepidermal water loss(TEWL),eczema area and severity index(EASI)score,total effective rate,degree of pruritus and traditional Chinese medicine quality of life scale(EPQOLS)score to evaluate the efficacy.[Results]Compared with the Western medicine treatment group at 2 w,the disappearance time of skin lesions in the integrated traditional Chinese and Western medicine group was shortened,TEWL,itching degree and EASI score,serum IgE and HA,and peripheral blood IL-4 levels were all decreased(P<0.05).IFN-γand IFN-γ/IL-4 ratio,anti-IgE antibody,EPQOLS score and total effective rate were all increased(P<0.05),and the difference was statistically significant.[Conclusions]Chuanbai antipruritic lotion"water film"wet compress combined with chloramphenicol prednisone liniment is an optimized and safe and efficient method for the treatment of acute eczema,which can quickly relieve the symptoms of inflammatory damage of eczema and restore the skin barrier function,dry dampness and relieve itch.Inhibition of the release of histamine active substances and regulation of immunity may be the main mechanisms.

超高效液相色谱-串联质谱法对奶粉中氯霉素残留的检测

A method was developed for the determination of chloramphenicol residue in milk powder by UPLC-MS/MS.The residue was extracted with ethylacetate from the milk powder,cleaned up by C18 SPE column,and detected by electrospray ionization and in the negative ion mode.The method had higher sensitivity and shorter analytical time,and was suitable for determination of chloramphenicol in milk powder.

Horizontal transfer of vanA between probiotic Enterococcus faecium and Enterococcus faecalis in fermented soybean meal and in digestive tract of growing pigs

Background: The aim of this study was to investigate the intergeneric transfer of vancomycin resistance gene vanA between probiotic enterococci in the fermentation progress of soybean meal and in the digestive tract of growing pigs.One vanA genotype vancomycin resistant E.faecium strain,Efm4,and one chloramphenicol-resistant E.faecalis strain,Efs2,were isolated from twenty-nine probiotic basis feed material/additive samples.For in vitro conjugation,Efm4 and Efs2 were used as starter to ferment soybean meal.For in vivo conjugation,thirty growing pigs were randomly assigned to five groups(n = 6),treated with a basic diet,or supplemented with 10% fermented soybean meal,1% Efm4,5% Efs2 or a combination of 1% Efm4 + 5% Efs2 for 7 d,respectively.Fecal samples of pigs in each group were collected daily for the isolation and dynamic analysis of Efm4,Efs2 and transconjugants.The sequence types(STs) of Efm4,Efs2 and transconjugants were analyzed by multilocus sequence typing(MLST).The vanA harboring plasmid in Efm4 and transconjugants was analyzed by S1-pulsed field gel electrophoresis(PFGE)and further verified by multiple alignments.Results: The results showed that,in FSBM,transconjugants were detected 1 h after the fermentation,with a conjugation frequency of ~ 10^-3 transconjugants/recipient.Transconjugants proliferated with Efm4 and Efs2 in the first 8 h and maintained steadily for 10 d till the end of the experiment.Additionally,in vivo experiment showed that transcojugants were recovered in one of six pigs in both FSBM and Efm4 + Efs2 groups,with conjugation frequency of ~ 10^-5 and ~ 10^-4,respectively.MLST revealed the ST of Efm4,Efs2 and transconjugants was ST1014,ST69 and ST69,respectively.S1-PFGE confirmed the existence of the vanA-harboring,142,988-bp plasmid,which was also a multi-drug resistant plasmid containing Tn1546-like transposon.Conclusions: The findings revealed the potential safety hazard existing in the commercial probiotic enterococci in China,because the horizontal transfer from farm to fork could potentially pose a safety risk to the public.

Synthesis and Structural Determination of (2R,4S,SS)-(+)-Threo-5-(2,2-dichloroacetamido)-4-(4-nitrophenyl)-2-aryl-1,3-dioxanes

(2R,4S,SS)-(+)-threo-5-(2,2-dicloroacetamido)-4-(4-nitrophenyl-2aryl-l,3dioxanes, were synthesized with high diastereoselectivity and good yields. The structuresofacetals were determined and the configurations were confirmed by 2D-NMR (NOESY).

Synthesis of Substituted Aziridine from (1S,2S)-2-Amino-1- (4-Nitrophenyl)- 1,3-Propanediol

(2S, 3R)-2-acetooxymethanyl-3-(P-nitrophenyl)-N-tosylaziridine 5 was synthesized from (1S, 2S)-2-amino-1-(4-nitrophenyl)-1, 3-propanediol 1 in four steps with a 24.8% overall yield. This reaction is stereospecific and occurs an expectable configuration inversion at α-carbon atom of benzyl group. The structure of substituted aziridine was determined on FT-IR, NMR, MS and so on.

Decomposition mechanism of chloramphenicol under electron beam irradiation

The purpose of this study was to evaluate the potential of electron beam to decompose chloramphenicol （CAP） in aqueous solutions. At the absorbed dose of 15 kGy, the decomposition rate of CAP was 95.24%. The degradation of CAP under electron beam irradiation followed pseudo-first-order kinetics. Redox reactions of CAP aqueous solutions with hydroxyl radicals （.OH）, hydrated electrons （eaq） and hydrated atoms （·H） were studied. The increase of the additives would result in the decrease of the degradation efficiency. The concentration of Cl- and NO3- in aqueous solution increased after electron beam irradiation. On the basis of the experimental results, a photocatalytic mechanism was discussed. The rate constant for reactions of .OH and CAP was 9.36×10^7 L/（mol.s） and for reaction of eaq and CAP was 7.33×10^7 L/（mol.s）..OH was supposed to play the key role in the radiation system of aqueous solution. Other free radicals like eaq and .H could also initiate the degradation.

Enhancing chloramphenicol and trimethoprim in vitro activity by Ocimum sanctum Linn.(Lamiaceae) leaf extract against Salmonella enterica serovar Typhi

Objective:To evaluate the antibacterial activity of Ocimum sanctum(O.sanctum) leaf extract, alone,and in combination with chloramphenicol(C) and trimethoprim(Tm) against Salmonella enterica serovar Typhi(S.typhi).Methods:The antibacterial activity of ethanolic extract of tulsi, 0.sanctum,leaf(TLE:500μg) for 23 S.typhi isolates was determined following agar diffusion. The C(30μg) and Tm(5μg) activity alone and in combination with TLE(250μg) was determined by disk diffusion.The zone diameter of inhibition(ZDI) for the agents was recorded, and growth inhibitory indices(Glls) were calculated.Results:The S.typhi isolates(n=23),which were resistant to both C(ZDI 6 mm) and Tm(ZDI 6 mm),had TLE(500μg) ZDIs 16-24 mm.The ZDIs of C and Tm were increased up to 15-21 mm and 17-23 mm,respectively,when TLE(250μg) was added to the C and Tm discs.The Glls ranged 0.789-1.235 and 0.894-1.352,due to combined activity against S.typhi isolates,of C and TLE and Tm and TLE.respeclivelv.Conclusions:The data suggest that TLE,in combination with C and Tm,had synergistic activity for S.typhi isolates, and hence O.sanclum is potential in combating S.typhi drug resistance,as well promising in the development of non-antibiotic drug for S.typhi infection.

Asymmetric Reduction of Aromatic Ketones Catalyzed by Using (αs,4s)-2-Dichloromethyl-4,5-Dihydro-α-(4-Nitrophenyl)-4- Oxazolemethanol-Borane Complex

Chiral oxazoborolidine borane complex was prepared from (αs, 4s)-2-dichloromethyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol with Borane in THF. The borane modified by chiral oxazoborolidine enantioselectively reduced aromatic ketones to second-alcohol with about 95%yield and medium optical yields. In the end of article, results are discussed and reduction mechanism is shown which proves the resulting major isomers fit very well.

Development of a surface plasmon resonance biosensor for accurate and sensitive quantitation of small molecules in blood samples

Therapeutic drug monitoring(TDM)has played an important role in clinical medicine for precise dosing.Currently,chromatographic technology and immunoassay detection are widely used in TDM and have met most of the needs of clinical drug therapy.However,some problems still exist in practical applications,such as complicated operation and the influence of endogenous substances.Surface plasmon resonance(SPR)has been applied to detect the concentrations of small molecules,including pesticide residues in crops and antibiotics in milk,which indicates its potential for in vivo drug detection.In this study,a new SPR-based biosensor for detecting chloramphenicol(CAP)in blood samples was developed and validated using methodological verification,including precision,accuracy,matrix effect,and extraction recovery rate,and compared with the classic ultra-performance liquid chromatographyultraviolet(UPLC-UV)method.The detection range of SPR was 0.1-50 ng/mL and the limit of detection was 0.099±0.023 ng/mL,which was lower than that of UPLC-UV.The intra-day and inter-day accuracies of SPR were 98%-114% and 110%-122%,which met the analysis requirement.The results show that the SPR biosensor is identical to UPLC-UV in the detection of CAP in rat blood samples;moreover,the SPR biosensor has better sensitivity.Therefore,the present study shows that SPR technology can be used for the detection of small molecules in the blood samples and has the potential to become a method for therapeutic drug monitoring.

Penetrating Ocular Trauma in a Goldfish Model after Chloramphenicol or Traditional Medicine Angong Niuhuang Pill Treatment: An Analysis of Retinal Responses after 7 Days

Purpose: While there were numerous clinical examples of ocular damage, the histopathology of retinal responses was poorly characterized, and animal model research was limited. The consequences of retinal lesions with traditional medicine treatment were mostly unknown. In this work, goldfish was employed as a model for penetrating injury of the eyes to study the ocular trauma with antibiotic and traditional medicine treatments. Materials and Methods: The penetration of the eyes was performed at 2mm above the midline of the limbus in the superior quadrant with an 18-gauge sterile needle, all the way to the retina but avoiding the lens while the animals were anaesthetized in water containing 100 mg/L ethyl 3-aminobenzoate methanesulfonate (MS-222). The animals were divided into three groups and received treatments of saline, chloramphenicol, and Angong Niuhuang pill (Angong) eyedrops twice a day respectively. Angong after seven days, the animals were sacrificed. Immunohistochemical evaluation of proliferative cell nuclear antigen (PCNA), brain-derived neurotrophic factor (BDNF), catalase, and cleaved caspase-3, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) for apoptotic cells were performed on the fish’s superior quadrants of the retinae. The whole experiment was repeated two times. Result: It was evident that both the retinae treated with chloramphenicol and Angong had fewer apoptotic cells and more proliferative cells, particularly in the cases of the Angong treatment. BDNF was in the inner nuclear layer and ganglion cell layer of all groups. In the chloramphenicol and Angong groups, some cells in the outer nuclear layer displayed BDNF. Catalase reactions confirmed equivalent findings that the treated retinae with chloramphenicol or Angong treatment had less catalase. Conclusion: Angong Niuhuang pill is a traditional medicine composite formula with antibiotic and neuroprotective effects on the brain and the eyes, and this work also pointed out its possible pharmaceutical potential.

Graphene from microwave-initiated upcycling of waste polyethylene for electrocatalytic reduction of chloramphenicol

Waste polyolefin plastics, accounting for 50% of all plastic waste, represent a tremendously unexploited carbon source. Efficiently upcycling polyolefin waste into value-added carbon materials for waste water treatment avoiding using noble metals is challenging but economically and environmentally sustainable. In this work, MAX-Ti_(3)AlC_(2) supported Fe selectively catalyzes polyolefin into few-layered graphene in 5 min under microwave treatment. Graphene and MAX supported Fe(Fe@MLC) can completely(99.9%)degrade chloramphenicol(CAP) within 60 min, retain robust after 10 cycles and work efficiently at a wide p H range(3.87–13.03), avoiding the usage of noble metal. Moreover, the electrochemical active surface area(ECSA) of Fe@MLC is 2.7 times higher than that of commercial Pt/C. This work provides a cheap and efficient catalyst that promotes deconstruction of plastic wastes and indirectly degrades antibiotics thereby realizes the treatment of waste water with waste plastic.

Mobile mini-fluorimeter for antibiotic aptasensing based on surface-plasmonic effect of burlike nanogolds enhanced by digitized imaging diagnosis

Antibiotic abuse now poses a grave threat to global ecology and bestirs public concerns about the residue issue in daily necessities.The traceability measurements along supply chain or logistic circulation have become increasingly essential given the labile nature of diverse synthetic residuals on site.In an attempt to answer this urgency,here a miniaturized fluorometric aptasensor prototype was contrived that catered to the point-of-care screening norm for two typical additives:chloramphenicol and enrofloxacin.The key target-indicating module worked in vitro based on the competitive binding-induced fluorescence recovery of fluorescein-labeled aptamers,which were photobleached beforehand in the format of double helix on burlike nanogold carriers.The“prickly”geometry of the latter not just enriched the capture probes at preferentially substrate-accessible spires;but also contributed to a tip-enhanced surface plasmon effect,sensitizing the signal-on during the duplex dissociation even at nanomolar threshold of the analytes.On the other hand,to encompass a full portable,a set of optical devices were mounted within a 3D-printed cartridge(adaptor)to converge the light beam and route it towards the detector,for which the smartphone camera came up in handy with a home-developed App for calibrating the emissive brightness.Enlightened by the high-dynamic-range compression,an imaging diagnostic algorithm was built in to grid and digitize each slide in the album for augmented detection performance.Thus,a novel bio-to-silico integration was invented that capable of in situ rapid reporting on the antibiotic presence with high sensitivity and selectivity.Further field practices in spiked milk on sales proved the precision and rudimentary feasibility of the well-assembled model of appliance,thus holding nice prospects in nonexpert(e.g.,family and local community)utilities for foodborne antibiotic identification.

Point-of-Care Testing of Chloramphenicol in Food Production Using Smartphone-Based Electrochemical Detector

Antibiotic abuse in food processing could threaten human health via either direct pathogen or drug-resistant infection.To curb this situation,it is of vital significance to identify trace level of antibiotics in foodstuffin a point-of-care inspection manner.Here,a smartphone-based electrochemical system was developed for the quantitation of chloramphenicol(CAP).The differential pulse voltammetric reduction of CAP was measured facilely on a piece of gold-deposited screen-printed electrode,which was docked onto a palm-sized detector with remote directives from a mobile APP of Bluetooth handshaking and digital display.Under optimal conditions,the target CAP could be determined in a range from 1 nmol/L to 5μmol/L with a detection limit of 0.25 nmol/L.Further tests on emulate samples demonstrated the miniaturized device could handle the food-screening scenarios with accuracy,convenience and quick response.

Simple synthesis of BiOI/ZnO/rGO for efficient photocatalytic degradation of antibiotic chloramphenicol under visible light

BiOI/ZnO/rGO(reduced graphene oxide) composite photocatalyst was fabricated using a simple one-step hydrothermal process and applied to the degradation of antibiotic chloramphenicol(CAP). By tuning the Bi/Zn ratios, the structure and photoelectric properties of the catalyst were investigated and characterized in terms of their morphological, structural, optical and photoelectrochemical properties. The as-synthesized composite photocatalysts are well-crystalline, uniform dispersion and exhibit good photocatalytic properties.The photocatalytic degradation rate of CAP by BiOI/ZnO/rGO composite is 8.1 times and 1.8times that of BiOI and ZnO, respectively. The photocatalytic mechanism studies revealed that the synergistic effect between rGO and BiOI/ZnO can effectively separate photogenerated electron–hole, enhance photocurrents and conductivity, and improve charge carrier densities. Moreover, BiOI/ZnO/rGO possesses good stability and reusability that the degradation efficiency remained above 80% even after 5 recycling. This study reveals that both the introduction of rGO and heterostructure construction between BiOI and ZnO play a crucial role in their photoelectrochemical and photocatalytic properties.

Capture-SELEX for Chloramphenicol Binding Aptamers for Labeled and Label-Free Fluorescence Sensing

Chloramphenicol(CAP)is a potent antibiotic.Due to its side effects,CAP is currently banned in most countries,but it is still found in many food products and in the environment.Developing aptamer-based biosensors for the detection of CAP has interested many researchers.While both RNA and DNA aptamers were previously reported for CAP,they were all obtained by immobilization of the CAP base,which omitted the two chlorine atoms.In this work,DNA aptamers were selected using the libraryimmobilized method and free unmodified CAP.Three families of aptamers were obtained,and the best one named CAP1 showed a dissociation constant(K_(d))of 9.8μM using isothermal titration calorimetry(ITC).A fluorescent strand-displacement sensor showed a limit of detection(LOD)of 14μM CAP.Thioflavin T(ThT)staining allowed label-free detection of CAP with a LOD of 1μM in buffer,1.8μM in Lake Ontario water,and 3.6μM in a wastewater sample.Comparisons were made with previously reported aptamers,and ITC failed to show binding of a previously reported 80-mer aptamer.Due to the small size and well-defined secondary structures of CAP1,this aptamer will find analytical applications for environmental and food monitoring.

Optimization of parameters on photocatalytic degradation of chloramphenicol using TiO_2 as photocatalyist by response surface methodology

The experimental design methodology was applied for modeling and optimizing the operation parameters on photocatalytic degradation of chloramphenicol （CAP） using TiO 2 as photocatalyst in a photoreactor. Three experimental parameters （including pH, TiO 2 concentration and CAP initial concentration） were adopted to obtain the preliminary information. The multivariate experimental design was employed to establish a quadratic model as a functional relationship between the degradation rate of CAP and three experimental parameters. The interaction effects and optimal parameters were obtained by using Design Expert software. The optimal values of the operation parameters under the related constraint conditions were found at pH 6.4, TiO 2 concentration of 0.94 g/L and CAP initial concentration of 19.97 mg/L, respectively. The degradation rate of CAP approached 85.97% under optimal conditions. The regression analysis with R 2 value of 0.9519 had a good agreement between the experimental results and the predictive values. In addition, pH and TiO 2 concentration had a significant influence on the degradation rate of CAP.

Analysis of chloramphenicol in honey by on-line pretreatment liquid chromatography-tandem mass spectrometry

hloramphenicol is an antibiotic and one of the potential contaminants in honey.Solid-phase extraction is the key pretreatment procedure for analysis of chloramphenicol in honey.In this work,an on-line pretreatment liquid chromatography-tandem mass spectrometer system for sensitive,reliable and higher throughput analysis was developed.With the methylcellulose-immobilized reversed-phase column,sugars in a honey sample were efficiently removed in 1 min.As a result,the limit of quantitation of chloramphenicol was 20 pg/mL（0.2 μg/kg honey）.

Thin-layered MoS_2/polyaniline nanocomposite for highly sensitive electrochemical detection of chloramphenicol

In this study, we synthesized molybdenum disulfide/polyaniline（MoS2/PANI） nanocomposite via in situ polymerization of aniline in the presence of thin-layered MoS2. The as-prepared MoS2/PANI nanocomposite obtained an improved electrochemical performance due to the physisorption interaction between aromatic aniline and the basal plane of MoS2. Furthermore, we constructed a new kind of electrochemical sensor based on MoS2/PANI nanocomposite for the detection of chloramphenicol, which showed an excellent performance. The sensor has a high sensitivity and wide detection range from 1 ×10^（-7）mol/L to 1×10^（-4）mol/L, with a low detection limit of 6.9 × 10^（-8）mol/L.