Chlortetracycline Research Articles

Field study on loss of tetracycline antibiotics from manure-applied soil and their risk assessment in regional water environment of Guangzhou, China

Tetracycline antibiotics (TCs) introduced into agricultural fields via manure application tend to accumulate in soils and further reach water environments via surface runoff and leachate, posing potential risks to regional water environment. This study investigated the loss of tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC) in surface runoff and leachate samples collected from a vegetable farmland with manure application in Guangzhou, South China. A risk assessment method was constructed for evaluating the ecological and health risks of manure-associated antibiotics released from soil into water environment. The results showed that the concentrations of three TCs in surface runoff, 30-cm leachate, and 60-cm leachate after the first rainfall event were 2.79–35.97, 1.71–18.44, and 0.4–2.66 μg/L, respectively, which all decreased with sampling depth and the time after rainfall events. Up to 0.13% of TCs were transported into the surface water through surface runoff, while less than 0.01% of TCs were transported into the groundwater through leachate at 60 cm. OTC had a higher total mass percentage (0.13%) into surface water via runoff than CTC (0.11%) and TC (0.07%) likely due to its smallest Kd value and largest input mass. Based on loss percentages, their predicted environmental concentrations (PEC) ranged from 4.87 (TC) to 16.91 (OTC) ng/L in regional surface water and 1.42 (TC) to 5.20 (CTC) ng/L in regional groundwater. The risk assessment based on PEC results suggested non-negligible health risk (HQ > 1.0 × 10−6) and low ecological risk (RQ < 0.1) in both regional surface water and groundwater, drawing concerns on the potential hazards of TCs released from manure-amended soil into water environments.

In-situ covalent bonding of carbon dots on two-dimensional tungsten disulfide interfaces for effective monitoring and remediation of chlortetracycline residue

• 2D WS 2 /CDs multifunctional nanomaterial was prepared by in-situ covalent bonding. • 2D WS 2 /CDs nanocomposite could be simultaneous detection and degradation of CTC. • The possible mechanisms for the detection and degradation of CTC were investigated. • This work is expected to provide a new idea for design of multifunctional platform. In view of the increasing threat of chlortetracycline (CTC) in water to human health and the ecological environment, how to detect and remove CTC in wastewater simply and effectively remains an important and challenging task. Herein, a multifunctional platform for the simultaneous detection and degradation of CTC is developed by in-situ synthesis of carbon dots (CDs) in the two-dimensional (2D) WS 2 interface by covalent bonding. The as-prepared 2D WS 2 /CDs nanocomposites can not only be used as an intelligent fluorescence probe for CTC detection with good sensitivity (LOD = 7.5 nM) and selectivity but also has good photodegradation ability for CTC (degradation efficiency attained 85.58%). Moreover, the possible mechanisms for the detection and photodegradation of CTC by 2D WS 2 /CDs were also investigated by theoretical calculations, time-resolved fluorescence decay curves, and electron spin resonance (ESR) analyses. The exceptional photoelectric properties of 2D WS 2 /CDs are ascribed to the CDs bound onto the 2D WS 2 interface by covalent bonding forming heterojunctions, which effectively promote strong interfacial interactions between CDs and 2D WS 2 , thereby providing more effective charge transfer and enhancing the detection efficiency and photocatalytic activity. In addition, the possible degradation pathway for CTC was speculated via identification of intermediates and frontier electron density calculation. Overall, this study not only proves that the 2D WS 2 /CDs nanocomposites have great potential for the simultaneous detection and degradation of CTC in aquatic environments but also provides a novel idea for the efficient and stable design of multifunctional nanomaterials for environmental pollution monitoring and purification, which is of great significance to both practical applications and basic research.

Effects of chlortetracycline on growth performance and intestinal functions in weaned piglets.

Weaning stress can cause serious damage to piglet's health. Chlortetracycline (CTC) is widely used to ameliorate weaning stress and prevent infectious diseases in weaned piglets. However, antibiotics as growth promoters have to be limited because of increased antimicrobial resistance. In this study, we evaluated the effects of CTC on growth performance and intestinal functions in order to provide evidence for seeking antibiotic substitutes in weaned piglets. A total of 20 weaned piglets were fed a basal diet or a diet supplemented with 75mg/kg CTC. CTC decreased the crypt depth and increased the ratio of villus height to crypt depth, whilst failing to affect growth performance and serum biochemical parameters and cytokines. 16S rRNA sequencing suggested that CTC supplementation had no effect on the diversity and composition of colonic microbiota. We speculated that gut microbiota is no longer sensitive to a low concentration of CTC due to the long-term use and low bioavailability of CTC in weaned piglets.

Eliminating tetracycline antibiotics matrix via photoactivated sulfate radical-based advanced oxidation process over the immobilized MIL-88A: Batch and continuous experiments

• The immobilized MIL-88A(Fe) onto cotton fibers (MC) was prepared. • MC was used to achieve efficient and long-term elimination of tetracyclines matrix. • A fixed bed reactor is constructed from MC in a home-made annular setup. • MC displayed boosted long-term stability in both batch and fixed bed tests. This work demonstrates the successful immobilization of MIL-88A(Fe) MOF on cotton fibers to fabricate MIL-88A(Fe)/cotton fibers (MC) by an eco-friendly method. The prepared MC is used to activate peroxydisulfate for eliminating multiple tetracycline antibiotics, such as oxytetracycline (OTC), tetracycline (TTC), and chlortetracycline (CTC) in simulated wastewater under UV-light irradiation. The photoactivated sulfate radical-advanced oxidation processes (SR-AOPs) towards the removal of tetracycline antibiotics matrix (initial concentration of 10.0 mg/L) using MC were initially investigated using a batch method. The results reveal that 97.5% OTC, 95.2% TTC, and 100.0% CTC can be degraded in the MC/UV/PDS system in the presence of 2 g/L of MC and 1 mM of PDS. The degradation pathways of OTC, TTC, and CTC were clarified via liquid chromatography-mass spectrometry analysis and DFT calculations. The quantitative structure–activity relationship analysis shows that the tetracycline antibiotics are transformed into their corresponding intermediates with lower toxicity within 8.0 min. A self-designed fixed bed reactor, in which the MC was packed into the annular channel, was adopted to test the long-term operation possibility of the MC in the continuous photoactivated SR-AOP system. The findings demonstrate that the whole antibiotics matrix can be removed completely within 22 h. This work is the first to demonstrate the use of MOFs as catalysts for SR-AOP to achieve continuous purification of simulated wastewater. The findings highlight a new possibility for the use of MOFs in large-scale wastewater treatment over.

Investigation of tetracycline residues in poultry meat samples from Dhaka city by high-performance liquid chromatography

The objective of the study was to quantify tetracycline (TCs) i.e., oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) residues in thirty poultry meat samples (n = 30) collected from the local market and super shop around the Dhaka University campus during May 2019 to January 2020. Three samples were collected from each of ten locations. All samples were extracted by Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method. Samples were analyzed by reversed-phase High-Performance Liquid Chromatograph equipped with Photo Diode Array Detector (LC-PDA) and a reported method was validated with good linear correlation coefficients of standards and matrix-matched calibration curves with r2=1.00, 0.99, 0.99 and r2= 0.99, 0.99,0.99 in the linearity range of 0-10 µg/kg for OTC, TC and CTC, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for OTC, TC, and CTC were 1.05, 1.17, and 1.09 μg/kg and 3.15, 3.51 and 3.27 μg/kg, respectively. Accuracy that is expressed by the recovery percentages were calculated at two different concentrations (2.5 and 5 μg/kg) were 91 and 100%, 102 and 100%, and 106 and 100% for OTC, TC, and CTC, respectively. Intra-day (n=3) and inter-day (n=9, 3 days) precision data were under 10% for all sample matrixes. Standard deviations were calculated ±0.06, ±0.11 and ±0.03 and precision (expressed by RSD%) were found 5.57, 9.14 and 2.35%, respectively for OTC, TC and CTC. The HPLC-PDA method is affordable for screening of large number meat samples for residual antibiotics in biological matrices by any laboratories. The method is also cheaper in comparison with LC-MSMS. Analysis of real 30 poultry meat samples showed that the tetracyclines residues were below the quantification limit in all samples.

Effects of honeycomb extract on the growth performance, carcass traits, immunity, antioxidant function and intestinal microorganisms of yellow bantam broilers

Although many studies have already described the physiological effects of bee products, such as honey, propolis, pollen, and royal jelly, on livestock farming, the health benefits of the honeycomb are still not fully understood. The problem of drug residues and bacterial resistance caused by the abuse of antibiotics is becoming increasingly serious. For this reason, a safe, green substitute has to be sought. We conducted a comparative study of honeycomb extract (HE) and an antibiotic on growth performance, carcass traits, immunity, antioxidant function and intestinal microorganisms of yellow bantam broilers. A total of four hundred eighty 21-day-old female yellow bantam broilers were randomly divided into 5 groups of 6 replicates of 16 birds each. The 5 groups were as follows, with birds receiving a basal diet supplemented with 150 ppm (mg/kg) of chlortetracycline (CTE), a basal diet without HE (control group), and a basal diet with 0.1%, 0.15%, or 0.2% HE for 60 days. The results showed that HE addition significantly increased average daily feed intake (ADFI), average daily gain (ADG), decrease feed gain ratio (F/G) from 21 to 80 and 51 to 80 days of age compared to the control group, with all 3 HE addition groups having statistically identical values to the antibiotic group. HE implementation dramatically increased spleen index, serum immunoglobulin A (IgA), immunoglobulin M (IgM,), glutathione peroxide (GSH-Px), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and total cecum bacteria and Lactobacillus compared to the control group, numerically at the same level as, or even better than, the antibiotic group. HE and CTE both markly reduced serum malondialdehyde (MDA) concentration compared to the control group, with higher concentrations of HE reducing the effect more dramatically than antibiotics. Both HE and CTE significantly raised dressed yield compared to the control group. In summary, HE, as a potential antibiotic alternative, improved growth performance, carcass traits, immune function, serum antioxidant capacity and intestinal microorganisms in yellow bantam broilers. According to the cubic regression analyses, the recommended supplemental dose of HE was calculated to be 0.15 to 0.17% for female yellow bantam broilers between 21 and 80 d of age.

A novel fluorescence ratio probe based on dual-emission carbon dots for highly selective and sensitive detection of chlortetracycline and cell imaging.

The novel dual-emission carbon dots (DECDs) for highly selective and sensitive recognition of chlortetracycline (CTC) and cell imaging were synthesized successfully by one-step synthesis. The obtained DECDs possessed two fluorescence peaks (345nm and 450nm) and showed specific response to CTC, resulting in a decrease in fluorescence intensity at 345nm, a blue shift, and an increase in fluorescence intensity at 450nm. The obtained DECDs exhibited highly selective response to CTC and not to its analogues, such as tetracycline, doxycycline, and oxytetracycline. Thus, an excellent ratiometric probe for the detection of CTC was fabricated successfully and used for the detection of CTC in real samples with the detection limit (LOD) of 16.45nM. More importantly, the DECDs were used for quantitative detection of CTC in living cells, which demonstrated excellent biocompatibility and broad prospects in biomedicine application. Finally, the excellent selectivity of DECDs toward CTC was attributed to the FRET mechanism and the formation of complexes.

ANTIMICROBIALS IN ANIMAL FAECES (CHICKEN, COW AND SWINE) FROM THE BREEDING FARMS IN THE UPSTREAM OF SAI GON RIVER

The widespread use of antimicrobials in husbandry has increased antimicrobial residues in animal faeces. Therefore, the investigation of antimicrobials in animal faeces is essential because they are the main cause of environmental pollution. This study analyzed and assessed samples of chiken, cow and swine faeces for seven antimicrobials, namely trimethoprim (TRI), ormethoprim (ORM), ofloxacin (OFL), norfloxacin (NOR), tetracycline (TET), chlortetracycline (CTE) and tylosin (TLS). Samples were taken from faeces heaps at breeding farms in the upstream of the Sai Gon river. The samples were analyzed in the laboratory by using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine antimicrobials. TRI, with the highest mean concentration, was found in all fecal samples (10,399 - 47,987 mg/kg) while ORM with the lowest average concentration was only detected in chicken fecal samples (542 mg/kg). CTE, with the second high mean concentration, was also found in all fecal samples (1,085 - 12,385 mg/kg), whereas TET was only detected in chicken fecal samples (9,050 mg/kg). OFL with the third average concentration, was aloso found in all fecal samples (1,516 - 9280 mg/kg), while NOR was detected in cow fecal samples at a low mean concentration (2,479 mg/kg). TLS was only found in chicken and cow fecal samples (798 - 5,802 mg/kg). These numbers show a very large amount of consumption of antimicrobials in livestock production. The results from this study are likely to encourage further monitoring of antimicrobials used in livestock production, and promote discussion of existing policies regarding the inclusion of antimicrobials in animal feed rations and veterinary medicines.

Hydroxyl radical and carbonate radical facilitate chlortetracycline degradation in the bio-photoelectrochemical system with a bioanode and a Bi2O3/CuO photocathode using bicarbonate buffer

The single-chamber bio-photoelectrochemical system (BPES) with a bioanode and a Bi2O3/CuO photocathode is developed for chlortetracycline (CTC) degradation under simulated solar irradiation, using phosphate buffer solution (PBS) or NaHCO3 as buffer solution. The optimized Bi2O3/CuO photocathode possesses rich vacancies, great photoresponse capability, and exhibits great photocatalytic activity toward CTC degradation due to its Z-scheme structure. Electron spin-resonance spectroscopy (ESR) and reactive species trapping experiments reveal that superoxide radicals/hydroxyl radicals are both the main radicals contributing to CTC degradation. Moreover, carbonate radical plays a more effective role toward CTC degradation, resulting in 40% improvement for CTC degradation in the BPES within 2 h. Higher current density (maximum of 137.6 A m−2) and more negative cathode potential are obtained from the illuminated BPES with NaHCO3 buffer. Possible mechanism and pathways of CTC degradation are proposed. This study contributes to the development of BPESs for antibiotics degradation.

Electrochemical synthesis of fluorescent carbon dots for the selective detection of chlortetracycline

Carbon dots (CDs) have been used for the fluorescent turn-on detection of chlortetracycline (CTC) with high selectivity and sensitivity. In this study, CDs were fabricated via electrochemical treatment using diethylenetriaminepentaacetic acid and ethylenediamine as precursors. The synthesized CDs exhibited blue fluorescence under ultraviolet irradiation and a maximum emission of 407 nm at an excitation wavelength of 325 nm; the calculated quantum yield was 2.5%. Moreover, the CDs demonstrated excellent water solubility and photobleaching resistance as well as good stability. In the presence of CTC, a considerable enhancement in fluorescence emission was observed, based on aggregation-induced emission enhancement owing to the complexation of CTC and CDs, thus providing the foundation for quantifying CTC. Under optimal conditions, the linear range was 0.8–10 μM (R2 = 0.9944), and the corresponding limit of detection was 16.9 nM. The proposed sensing system was successfully applied for determining CTC in actual samples with good recoveries between 91.3% and 110.6%.

The residue of tetracycline antibiotics in soil and Brassica juncea var. gemmifera, and the diversity of soil bacterial community under different livestock manure treatments.

Tetracycline antibiotics (TCs) are a broad-spectrum antibiotic, widely used in livestock and poultry breeding. Residue of tetracycline antibiotics in animal manure may cause changes in vegetable TCs content and soil microbial community. On the basis of the investigation and analysis of TCs pollution in the soil of main vegetable bases and the livestock manure of major large-scale farms in Chongqing, China, field experiment was conducted to study the residues of tetracycline antibiotics in Brassica juncea var. gemmifera and soil under different kinds and different dosages of livestock manures. Effects of tetracycline antibiotics on the structure and diversity of soil microbial community were also investigated by high-throughput sequencing. TCs content in soil was increased by applying livestock manure. The contents of tetracycline, oxytetracycline (OTC) and chlortetracycline (CTC) in the soil under pig manure treatment were 171.07-660.20μgkg-1, 25.38-345.78μgkg-1 and 170.77-707.47μgkg-1, respectively. The contents of TC, OTC and CTC in the soil under the treatment of chicken manure were 166.62-353.61μgkg-1, 122.25-251.23μgkg-1 and 15.12-80.91μgkg-1, respectively. TCs in edible parts of Brassica juncea var. gemmifera was increased after livestock manure treatment Proteobacteria, Acidobacteria, Actinobacteria, Chioroflexi and Bacteroidetes under livestock manure treatment were the dominant phyla, accounting for 85.2-92.4% of the total abundance of soil bacteria. The soil OTUs under the treatment of pig manure was higher than that under the treatment of chicken manure. Biogas residue (Livestock manure after fermentation treatment) can effectively reduce the environmental and ecological risks caused by antibiotic residues.

Rational design of in‐situ‐modified resorcinol formaldehyde aerogels for removing chlortetracycline antibiotics from aqueous solutions

AbstractOrganic resorcinol formaldehyde aerogels with distinct pore sizes/surface areas in different ratios of (resorcinol/catalyst) R/C = 300, 400, 600 and (resorcinol/water) R/W = 2 were prepared utilizing sol–gel technique and in‐situ modified by incorporating 1 wt% meta‐phenylenediamine. The porous nanostructure, surface area, and pore size of the aerogels were characterized by scanning electron microscopy, Brunauer–Emmett–Teller, and Barrett–Joyner–Halenda techniques. Raman spectroscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction were employed to get understanding into the chemical structure. Furthermore, we investigated the removal percentage of antibiotic via UV–vis spectroscopy. The ability of modified aerogels in removing chlortetracycline (CTC) at different pH values (2–12), contact times (2–24 h), initial concentrations of CTC (50–100 mg L−1), and the adsorbent dose (2–10 mg) was evaluated. Consequently, the adsorption optimum conditions were found, the adsorption isotherms were measured, and isotherm models were fitted to the results to interpret the kinetics of adsorption. The obtained fitting parameters using the pseudo‐second‐order model revealed a well alignment with the experimental data. Finally, we demonstrated that the modified‐aerogels have a high capacity in CTC antibiotics removal up to 90% and an adsorption capacity of 440 mg g−1 as well as an efficient regeneration capacity for five consecutive cycles without significant degradation of the adsorption properties.

Supplementation of Mito TEMPO and acetovanillone in semen extender improves freezability of buffalo spermatozoa.

Oxidative stress is one of the leading factors responsible for poor post-thaw semen quality because of overproduction of reactive oxygen species (ROS) over neutralizing antioxidants present in semen. Mainly two ROS generation sites are present in spermatozoa, that is, mitochondria and plasma membrane. Therefore, the idea of targeting these specific sites for minimization of ROS production with the compounds having known mechanism of actions was built up as a core for this research. Present study was done to investigate the effects of Mito TEMPO and acetovanillone individually and in combination on freezability of buffalo spermatozoa. For the experiment, semen extender was supplemented with Mito TEMPO (50 μM), acetovanillone (50 μM), and a combination of Mito TEMPO + acetovanillone (50 μM+ 50 μM), designated as Group II, Group III, and Group IV, respectively. Control group without any supplementation was designated as Group I. A total of 24 ejaculates with individual progressive motility (IPM) of ≥70% were selected for the study. After final dilution, filling-sealing of straws, equilibration, and freezing were done as per the standard procedure. Semen samples were evaluated for IPM, plasma membrane integrity, lipid peroxidation, total antioxidant capacity (TAC), and cholesterol to phospholipids (C/P) ratio at both fresh and post-thaw stages. Evaluation of ROS, mitochondrial membrane potential (MMP), capacitation status (CTC assay), and in vitro fertility potential were conducted only on frozen-thawed samples. The addition of Mito TEMPO (50 μM) and acetovanillone (50 μM) individually and in combination significantly (p<0.05) improved post-thaw semen quality in terms of IPM, plasma membrane integrity, TAC, cholesterol content, C/P ratio, MMP, Chlortetracycline (CTC)-Full (F) pattern, and zona binding ability of buffalo spermatozoa, while significantly (p<0.05) reduced ROS production, lipid peroxidation, and capacitation like changes as compared to the control group. As Mito TEMPO acts as an SOD mimetic and also detoxifies ferrous iron at the mitochondria level, it aids in neutralization of excessive ROS production and minimizes oxidative stress-related damages that enhances the antioxidant potential of sperm mitochondria. Earlier studies also indicated improved post-thaw semen quality in 50 μM supplemented group. The improvement observed in acetovanillone (50 μM) group might be because of inhibition of Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase as this enzyme activation by various physical/chemical inducers during cryopreservation process leads to activation of CatSper channel resulting in calcium influx, premature capacitation, and acrosomal reaction like changes through activation of adenylate cyclase and cAMP/PKA-mediated tyrosine phosphorylation of sperm proteins. Acetovanillone also prevents NADPH oxidase-mediated inhibition of glutathione reductase activity, which has a vital role in protecting the structural and functional integrity of sperm plasma membrane. Results indicated beneficial effects of supplementation of Mito TEMPO and acetovanillone on sperm freezability and individual supplementation was as efficient as the combination group for sustaining post-thaw semen quality.

Atomic Fe sites embedded within carbon nanotubes for the efficient photodegradation of multiple tetracyclines

We have constructed a series of mesoporous carbon nanotube (CNT) networks loaded with trace atomic Fe sites (denoted as Fe-CNTs) by calcining a melamine–cyanuric acid complex and glucose absorbed with Fe3+ (denoted as MCA/G–Fe3+) at different high temperatures (800 °C, 900 °C, and 1000 °C) under N2 atmosphere. The series of Fe-CNT hybrids were then utilized as efficient catalysts for the photodegradation of different types of tetracyclines (TCs), including tetracycline hydrochloride (TCH), chlortetracycline (CTC), and oxytetracycline (OTC), under visible-light irradiation. The mesoporous multiple-layered structure of CNTs not only efficiently inhibited the aggregation of active Fe species but also afforded the hybrids with fast electron transfer and charge separation abilities. Among the three catalysts obtained, Fe-CNT-900, which was synthesized by annealing the MCA/G–Fe3+ complex at 900 °C, demonstrated multifunctionality and intertwined carbon rings. As compared with other catalysts, Fe-CNT-900 showed higher porosity, larger specific surface area, and superior magnetic performance. Thereby, Fe-CNT-900 exhibited significantly improved photocatalytic efficiency toward TCH, CTC, and OTC, showing high photodegradation rates of 93.2%, 99.4% and 94.3%, respectively, under optimal conditions. Trapping experiments and electron spin resonance analysis confirmed that superoxide (•O2−) and hydroxyl (•OH) radicals played essentials roles during photocatalysis. Moreover, the degradation mechanisms and pathways of diverse antibiotics were proposed, while the toxicities of the degradation products of TCs were assessed via the growth of Escherichia coli. The present work provides novel insights into the design of highly efficient Fe-N-C-based photocatalysts for the treatment of harmful pharmaceutical pollutants.

The distribution and ecological risks of antibiotics in surface water in key cities along the lower reaches of the Yellow River: A case study of Kaifeng City, China

A large number of antibiotics have been discharged into rivers by human activities, posing a threat to aquatic ecosystems. The surface water of the Yellow River Basin also suffers antibiotic pollution, which hinders the improvement in the aquatic ecological environment. This study investigated and analyzed the characteristics and assessed the ecological risks of antibiotic pollution in surface water bodies such as canals, rivers and fish ponds in Kaifeng, Henan Province, which is a key city along the lower reaches of the Yellow River. The test results are as follows. A total of 15 types of antibiotics were detected in the surface water. They had a total antibiotic concentration of 12.2–249.9 μg/L, of which tetracyclines (TCs) and quinolones accounted for the highest percentages. Six types of quinolones had detection rates of up to 100%, and doxycycline (DC) and oxytetracycline (OTC) had average concentrations of 29.52 μg/L1 and 13.71 μg/L, respectively. The major canals with water diverted from the Yellow River had total concentrations of quinolones and TCs of 22. 0 μg/L and 14.9 μg/L, respectively, which were higher than those in previous studies. This phenomenon may be related to the decrease in the water flow of the Yellow River during the dry season and the increase in the antibiotic consumption of residents in the context of the Covid-19 outbreak. The upper reaches of the Huiji River in the Xiangfu District had higher antibiotic content than other districts in Kaifeng. Specifically, TCs accounted for 72.38%–91.84% of all antibiotics, and the DC and OTC concentrations were significantly higher than other antibiotics in the upper reaches. As indicated by the ecological risk assessment results, TCs had the highest ecological risks to green algae. Among them, DC had medium-high risks; TC, OTC, and chlortetracycline (CTC) had medium-high risks; trimethoprim (TMP) and lomefloxacin (LOM) had low risks; other TC antibiotics had no risk. Compared with green algae, most antibiotics showed higher ecological risks to daphnia and lower ecological risks to fish. DC and OTC dominate antibiotic pollutants in the surface water in Kaifeng City, and especially in Xiangfu District, where DC and OTC have medium-high risks. The TCs in the major Yellow River showed medium risks to both green algae and daphnia. It can be speculated that the antibiotic pollution in the Yellow River might pose a certain threat to the ecological security of water in Kaifeng City.©2022 China Geology Editorial Office.

Online prediction of total sugar content and optimal control of glucose feed rate during chlortetracycline fermentation based on soft sensor modeling.

In the process of chlortetracycline (CTC) fermentation, no instrument can be used to measure the total sugar content of the fermentation broth online due to its high viscosity and large amount of impurities, so it is difficult to realize the optimal control of glucose feed rate in the fermentation process. In order to solve this intractable problem, the relationship between on-line measurable parameters and total sugar content (One of the parameters that are difficult to measure online) in fermentation tank is deeply analyzed, and a new soft sensor model of total sugar content in fermentation tank and a new optimal control method of glucose feed rate are proposed in this paper. By selecting measurable variables of fermentation tank, determining different fermentation stages, constructing recursive fuzzy neural network (RFNN) and applying network rolling training method, an online soft sensor model of total sugar content is established. Based on the field multi-batch data, the change trend of the amount of glucose feed required at each fermentation stage is divided, and the online prediction of total sugar content and the optimal control strategy of glucose feed rate are realized by using the inference algorithm of expert experience regulation rules and soft sensor model of total sugar content. The experiment results in the real field demonstrate that the proposed scheme can effectively predict the total sugar content of fermentation broth online, optimize the control of glucose feed rate during fermentation process, reduce production cost and meet the requirements of production technology.

Luminescent porous metal–organic gels for efficient adsorption and sensitive detection of chlortetracycline hydrochloride assisted by smartphones and a test paper-based analytical device

Three porous and luminescent JLUE-MOGs are fabricated for the efficient removal of CTC, and on-site rapid and sensitive detection of CTC with the help of paper and a smartphone is realized.

Selective Adsorption and Photocatalytic Degradation of Chlortetracycline Hydrochloride by La2ti2o7/Acid-Modified Coal Bearing-Strata Kaolinite Composite

Selective Adsorption and Photocatalytic Degradation of Chlortetracycline Hydrochloride by La2ti2o7/Acid-Modified Coal Bearing-Strata Kaolinite Composite

CdTe QDs@ZIF-8 composite-based recyclable ratiometric fluorescent sensor for rapid and sensitive detection of chlortetracycline

The residue problem in animal food products caused by the abuse of chlortetracycline (CTC) is one of the food safety issues that have attracted much attention. Herein, a composite was generated by embedding CdTe quantum dots (QDs) into ZIF-8 for ratiometric fluorescent analysis of CTC. With adding CTC, the green luminescence of CTC appeared under the sensitization effect of Zn2+ in ZIF-8, but the red luminescence of CdTe QDs was reduced by the inner filtration effect of CTC. On this basis, CTC was detected by the composite with a short response time of 1 min, and the limit of detection was calculated to be 37 nM that was 17 times lower than the maximum residue limit of CTC in animal food products (626 nM). Excellent recyclability of the composite was also observed, and CTC was consecutively measured at least six times. The composite was used to determine CTC in basa fish and pure milk with satisfactory recoveries (91.0–110.0%). Portable test strips were further manufactured and the visual determination of CTC was obtained. These results convictively demonstrate that CdTe QDs@ZIF-8 composite as a recyclable ratiometric fluorescent sensor achieves the rapid and sensitive measurement of CTC residue in animal food products.

Extensive solar light utilizing by ternary C-dots/Cu2O/SrTiO3: Highly enhanced photocatalytic degradation of antibiotics and inactivation of E. coli

Fabrication of a visible-light driven photocatalyst is of great vital for the elimination of antibiotics and microorganism in the wastewater and the construction of sustainable green energy systems. In this work, carbon quantum dots (C-dots) were integrated with Cu2O/SrTiO3 p-n heterojunction to optimize the photocatalytic activity. The excellent photocatalytic degradation efficiency of chlortetracycline hydrochloride (CTC·HCl) (92.6% within 90 min) and E. coli inactivation efficiency were observed over C-dots/Cu2O/SrTiO3 under visible light irradiation. It is the synergistic effect of p-n heterojunction and modification of C-dots that facilitates the separation and transfer of electron-holes. Meanwhile, the modification of C-dots improves the harvesting of long wavelength solar light of photocatalysts due to its unique up-conversion photoluminescence (UCPL) characteristics. Eventually, the possible photocatalytic degradation path of the catalyst was inferred by LC-MS spectra, and the degradation mechanism was analyzed. This study sheds light on new possibilities for the application of photocatalysts in various light sources and has broad application prospects in water treatment.