Simultaneous extraction and determination of antibiotics in soils using a method based on quick, easy, cheap, effective, rugged, and safe extraction and liquid chromatography with tandem mass spectrometry

Distribution pattern analysis of multiple antibiotics in the soil-rice system using a QuEChERS extraction method

Antibiotics are commonly released into paddy fields as mixtures via human activities. However, the simultaneous extraction and detection of these chemicals from multiple media are technically challenging due to their different physicochemical properties, resulting in unclear patterns of their transport in the soil-rice system. In this study, a "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method was developed for the simultaneous analysis of 4 tetracyclines (TCs) and 4 fluoroquinolones (FQs) in the soil and rice tissues from a local poultry farm, and thereby the distribution patterns of the target antibiotics in the soil-rice system and their risk levels to the soil were analyzed. After parameter optimization, the calibration range used for the target antibiotics was 0.1-50 μg/L and each calibration curve was linear with a coefficient of determination (R2 > 0.995); The QuEChERS method achieved satisfactory recovery rates (70.3-124.6%) along with sensitive detection limits (0.005-0.21 ng/g) for TCs and FQs in the soil, root, stem, leaf, and grain. Among the 8 antibiotics, enrofloxacin (ENX), ciprofloxacin (CIP), oxytetracycline (OTC), and doxycycline (DOX) were detected around a poultry farm. The four antibiotics in the collected paddy soils around the poultry farm ranged from 7.1 ng/g to 395.5 ng/g. Notably, ENX and DOX had higher ecological risks (risk quotient values >1) than CIP and OTC in soil. ENX, CIP, and DOX were highly enriched in rice roots with concentrations up to 471.9, 857.3, and 547.4 ng/g, respectively, which were also detected in rice aboveground tissues. The findings may provide both technical and practical guidance for the understanding of antibiotic environmental behavior and risks.

Multitarget and suspect-screening of antimicrobials in vegetables samples: Uptake experiments and identification of transformation products

This work provided an accurate analytical method to perform a multitarget analysis of a variety of antimicrobials (AMs) including sulfonamides, tetracyclines, macrolides, fluoroquinolones and quinolones, one imidazole and one nitroimidazole, one triazole, one diaminopyridine and one derivative of Penicillium stoloniferum in vegetables. The analysis is performed using liquid-chromatography coupled to a low-resolution triple quadrupole mass spectrometer (UHPLC-MS/MS) to detect the target analytesor coupled to a high-resolution q-Orbitrap (HRMS) to monitor the formed transformation products (TPs). Both instruments were compared in terms of limits of quantification and matrix effect at the detection. The method was applied to determine the presence of AMs in organic and non-organic vegetables, where sulfadiazine and mycophenolic acid were detected. On the other hand, the transference of four AMs (trimethoprim, sulfamethazine, enrofloxacin, and chlortetracycline) from soils to lettuces was evaluated through controlled uptake experiments. The choice of AMs was based on the classification into different families, and on the fact that those AM families are the most frequently detected in the environment. In this case, each of the AMs with which the soils were contaminated were found in the exposed lettuces. Moreover, in both studies, specific TPs of the AMs were identified, posing the necessity of assessing their effects in relation to food and human safety.

Evaluation of different QuEChERS-based methods for the extraction of 48 wastewater-derived organic contaminants from soil and lettuce root using high-resolution LC-QTOF with MRMHR and SWATH acquisition modes

The reuse of treated wastewater in agriculture is an important route of introducing a large number of organic contaminants into the agroecosystem. In this study, a modified QuEChERS-based approach was developed for rapid, simple, and simultaneous extraction of 48 organic wastewater-derived contaminants from soil and lettuce root. Twenty-two different (modification) scenarios of the known (or original) QuEChERS method have been tested, in order to obtain best and well-compromised recoveries for all target compounds for soil and roots. Finally, a common method was chosen for both matrices consisting of a single extraction step using EDTA-Mcllvaine buffer and the unbuffered Original QuEChERS salts. Method performance was accomplished by liquid chromatography coupled with high-resolution mass spectrometry on a QToF-MS system using two different acquisition modes, the ultra-fast high-resolution multiple reaction monitoring (MRMHR) mode and the innovative Sequential Window Acquisition of All Theoretical Fragment-Ion (SWATH) mode. Performance characterization was evaluated in terms of recovery, linearity, intra-day precision, method detection limits (MDLs), method quantification limits (MQLs), and matrix effect (ME). Recoveries in MRMHR mode ranged from 63 to 111% and 54 to 104% for lettuce root and soil, respectively, for most of compounds in MRMHR mode and from 56 to 121% and 54 to 104% for lettuce root and soil, respectively, for most of compounds in SWATH. Whereas, MQLs ranged from 0.03 to 0.92 ng g-1 in MRMHR and from 0.03 to 82 ng g-1 in SWATH for lettuce root, and from 0.02 to 0.44 ng g-1 in MRMHR and 0.02 to 0.14 ng g-1 in SWATH for soil. The method was then applied to follow the target compounds in soil and lettuce root, where the system lettuce-soil was irrigated with treated wastewater under real greenhouse conditions. Five and 17 compounds were detected in lettuce root and soil, respectively.

Simultaneous determination of 13 sulfonamides at trace levels in soil by modified QuEChERS with HPLC-MS/MS

The pretreatment of samples was vital for enhancing the sensitivity and accuracy of analytical methods. An efficient and sensitive method, based on modified QuEChERS with high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of the 13 sulfonamides (SAs) in soil, was developed. After extraction by sonication with methanol, the clean-up procedure was achieved using QuEChERS with a primary secondary amine (PSA). The quantification of the 13 SAs was performed by HPLC-MS/MS in electrospray ionization (ESI) and multiple reaction monitoring (MRM) modes. Under optimized conditions, the standard solution exhibited good linearity within the range of 0.01-0.5 μg mL-1. The limits of detection and the limits of quantification of the developed method were 0.007-0.030 μg kg-1 and 0.022-0.101 μg kg-1, respectively. The spiked recoveries for the 13 SAs were in the range of 74.5-111.7% with RSD less than 15%. Furthermore, the developed method was successfully applied for the determination of SAs in real soil samples. The above results showed that the proposed method would be an ideal analytical method for SAs in environmental ecological research.

Multitarget and suspect screening of antimicrobials in soil and manure by means of QuEChERS - liquid chromatography tandem mass spectrometry

The present work aimed to develop an accurate analytical method for the simultaneous analysis of twenty-four antimicrobials in soil:compost and animal manure samples by means of ultra-high performance liquid chromatography coupled to a triple-quadrupole mass spectrometer (UHPLC-QqQ). For this purpose, the effectiveness of two extraction techniques (i.e. focused ultrasound solid-liquid extraction (FUSLE) and QuEChERS (quick, easy, cheap, effective, rugged and safe)) was evaluated, and the clean-up step using solid-phase extraction (SPE) was also thoroughly studied. The method was successfully validated at 10 μg·kg-1, 25 μg·kg-1, and 50 μg·kg-1 showing adequate trueness (70-130%) and repeatability (RSD < 30%), with few exceptions. Procedural limits of quantification (LOQPRO) were determined for soil:compost (0.45 to 7.50 μg·kg-1) and manure (0.31 to 5.53 μg·kg-1) samples. Pefloxacin could not be validated at the lowest level since LOQPRO ≥ 10 μg·kg-1. Sulfamethazine (7.9 ± 0.8 µg·kg-1), danofloxacin (27.1 ± 1.4 µg·kg-1) and trimethoprim (4.9 ± 0.5 µg·kg-1) were detected in soil samples; and tetracycline (56.8 ± 2.8 µg·kg-1), among other antimicrobials, in the plants grown on the surface of the studied soil samples. Similarly, sulfonamides (SAs), tetracyclines (TCs) and fluoroquinolones (FQs) were detected in sheep manure in a range of 1.7 ± 0.3 to 93.3 ± 6.8 µg·kg-1. Soil and manure samples were also analysed through UHPLC coupled to a high-resolution mass-spectrometer (UHPLC-qOrbitrap) in order to extend the multitarget method to suspect screening of more than 22,281 suspects. A specific transformation product (TP) of sulfamethazine (formyl-sulfamethazine) was annotated at 2a level in manure samples, among others. This work contributes to the efforts that have been made in the last decade to develop analytical methods that allow multitarget analysis of a wide variety of antimicrobials, including TPs, which is a complex task due to the diverse physicochemical properties of the antimicrobials.

Recent perspective of antibiotics remediation: A review of the principles, mechanisms, and chemistry controlling remediation from aqueous media

Antibiotic pollution is an ever-growing concern that affects the growth of plants and the well-being of animals and humans. Research on antibiotics remediation from aqueous media has grown over the years and previous reviews have highlighted recent advances in antibiotics remediation technologies, perspectives on antibiotics ecotoxicity, and the development of antibiotic-resistant genes. Nevertheless, the relationship between antibiotics solution chemistry, remediation technology, and the interactions between antibiotics and adsorbents at the molecular level is still elusive. Thus, this review summarizes recent literature on antibiotics remediation from aqueous media and the adsorption perspective. The review discusses the principles, mechanisms, and solution chemistry of antibiotics and how they affect remediation and the type of adsorbents used for antibiotic adsorption processes. The literature analysis revealed that: (i) Although antibiotics extraction and detection techniques have evolved from single-substrate-oriented to multi-substrates-oriented detection technologies, antibiotics pollution remains a great danger to the environment due to its trace level; (ii) Some of the most effective antibiotic remediation technologies are still at the laboratory scale. Thus, upscaling these technologies to field level will require funding, which brings in more constraints and doubts patterning to whether the technology will achieve the same performance as in the laboratory; and (iii) Adsorption technologies remain the most affordable for antibiotic remediation. However, the recent trends show more focus on developing high-end adsorbents which are expensive and sometimes less efficient compared to existing adsorbents. Thus, more research needs to focus on developing cheaper and less complex adsorbents from readily available raw materials. This review will be beneficial to stakeholders, researchers, and public health professionals for the efficient management of antibiotics for a refined decision.

Quantification of docusate antimicrobial finishing after simulated landfill degradation via tandem mass spectrometry and QuEChERS extraction

An analytical method for the detection and quantification of silver docusate antimicrobial finishing in soil was developed through a combination of the QuEChERS extraction method and tandem mass spectrometry (MS/MS) quantification with isotopically labeled internal standard. First, the calibration system was established in the matrix where QuEChERS extraction removed docusate from soil. The addition of an isotopically labeled internal standard reduces ionization suppression due to instrumental fluctuation and run-to-run deviation. After establishing the calibration system, this quantification method was validated according to a guideline from the U.S. Food and Drug Administration. A series of variables for quantification were validated including coefficient of determination (R² = 0.989 ± 0.002), percent error (% error = 3 ± 4%), coefficient of variation (% CV = 6 ± 1%), limit of detection (LOD = 8 ± 2 ng mL^-1), lower limit of quantification (LLOQ = 27 ± 5 ng mL^-1), recovery and matrix effect (matrix effect = 0.944 ± 0.026). Those parameters were obtained from the inter- and intra-day measurements for both calibration and the quality control standards. Later, samples extracted from a simulated landfill degradation of cotton fabrics applied with sliver docusate antimicrobial finishing were measured. It was observed that the concentration measured (51 ± 5 ng mL^-1 or 252 ± 25 ng g^-1) fell into the ranges defined by the method development with good precision (% CV = 4 ± 1%). Results from this study could further the understanding of textile landfill degradation and facilitate further study regarding docusate contamination in soil.

Syringe purification with UPLC-MS/MS for detection of antibiotics in tea garden soil after long-term application of manure

The residue of antibiotics in the soil is becoming more and more common, which may affect the normal growth of plants and organisms. The aim of this study was to investigate the residues of antibiotics in tea gardens' soil after a long-term application of manure. An ultra-high performance liquid chromatography-tandem mass spectrometry method was developed to simultaneously determine the residues of 32 antibiotics in the soil of tea gardens after fertilization. The samples were extracted with methanol-acetonitrile and purified with C18 at the same time. Then, mixed dispersive sorbents dispersed in a syringe were used for the second purification. The results showed that the antibiotics have a good linear relationship within the range. The recovery rate is 70.1-120.3%. The applicability of the method was demonstrated by analyzing 30 real samples (with a detection rate of 43.3%). The method is a simple and environmentally friendly method for the analysis of multiple antibiotics in soils, and it could provide a basis for the risk assessment of antibiotics in agricultural environments and the standard application of organic fertilizers in tea gardens.

Novel and simple analytical method for simultaneous determination of sulfonamide, quinolone, tetracycline, macrolide, and chloramphenicol antibiotics in soil

The multiclass determination of antibiotic residues in the soil is challenging because of its complex physicochemical properties. In this study, a simple analytical method was developed to simultaneously extract and determine 58 antibiotics from the soil. A novel acidity-regulated extraction-partition-concentration protocol was established for the simultaneous extraction of five classes (23 sulfonamides, 18 quinolones, five tetracyclines, eight macrolides, and four chloramphenicols) of antibiotics from the soil. Compared to traditional methods, the sample preparation efficiency was significantly improved by four times (45 min vs. 230 min) by optimizing the extraction method and omitting the time-consuming solid-phase extraction (SPE) procedure. The ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was optimized to determine the 58 antibiotics in a single run by applying positive/negative switching acquisition mode in less than 10 min with the baseline separation of sulfameter and sulfamethoxypyridazine. Suitable recoveries, ranging between 60 and 120%, were obtained for most antibiotics, with RSD <20%. The limits of quantification (LOQ) of the method were 2 μg/kg and 5 μg/kg. Thus, this study provides a simple, reliable, and economical method for accurately and rapidly determining a multiclass of antibiotics in the soil.

Determination of multiple antibiotics in agricultural soil using a quick, easy, cheap, effective, rugged, and safe method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry

In this study, we combined ultra-high performance liquid chromatography with tandem mass spectrometry to establish a quick, easy, cheap, effective, rugged, and safe method of detecting 21 target antibiotics in agricultural soil samples. Antibiotics were extracted with mixed solvents consisting of ethylenediaminetetraacetic acid disodium salt dihydrate and phosphoric acid citric acid buffer and acetonitrile which were purified with octadecylsilyl as an adsorbent and anhydrous sodium sulfate as a desiccant. This method was able to effectively extract all of the target antibiotics from agricultural soils, with recovery efficiencies ranging from 55 to 108% and limits of detection between 0.09-0.68 μg/kg. We also validated this new method for selectivity, sensitivity, and reliability of detecting multiple antibiotics in 12 samples. Considering the potential environmental and public health effects of antibiotics in agricultural soils, our new method can help analyze the degree of antibiotic contamination and provide valuable information for soil quality and risk assessment.

Application of UHPLC-MS/MS method to study occurrence and fate of sulfonamide antibiotics and their transformation products in surface water in highly urbanized areas

Sulfonamide antibiotics (SAs) are used on a large scale in human and veterinary medicine. The main goal of this study was to develop a method for the detection of selected SAs (sulfamethoxazole, sulfadiazine, sulfamethazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethiazole, and sulfisoxazole) in aqueous samples (targeted analysis), and then conduct a non-targeted analysis to determine the transformation products to elucidate their degradation pathways. These analyses were performed using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The procedure was used to detect selected antibiotics in water samples collected throughout a highly urbanized area. Among the studied compounds, sulfamethoxazole (max. 78.88 ng L^-1) and sulfapyridine (max. 38.88 ng L ^-1) were the most common pollutants identified in surface waters. Trace amounts of sulfadiazine (below LOQ = 0.40 ng L^-1) were also detected. Next, the samples were screened to detect the transformation products. Several sulfadiazine and sulfamethoxazole transformation products were detected and confirmed in the environmental samples.

Enhanced control of sulfonamide resistance genes and host bacteria during thermophilic aerobic composting of cow manure

Traditional composting has already shown a certain effect in eliminating antibiotic residues, antibiotic-resistant bacteria (ARBs), and antibiotic resistance genes (ARGs). It is worth noting that the rebounding of ARGs and the succession of the bacterial community during conventional aerobic composting are still serious threats. Considering the probable risk, improved and adaptable technologies are urgently needed to control antibiotic resistance efficiently. This study monitored how thermophilic aerobic composting affected the ARGs, as well as the bacterial diversity during the composting of cow manure spiked with sulfamethoxazole (SMX) at different concentrations. Results showed that the degradation of SMX was enhanced during thermophilic aerobic composting (control > SMX25 > SMX50 > SMX100) and was no longer detected after 20 days of composting. High temperature or heat significantly stimulated the rebounding of certain genes. After 35 days, the abundance of detected genes (sul2, sulA, dfrA7, and dfrA1) significantly decreased (p < 0.05) in control and antibiotic-spiked treatments, except for sul1. The addition of three concentrations of SMX elicited a sharp effect on bacterial diversity, and microbial structure in SMX25 led to significant differences with others (p < 0.05). The network analysis revealed more rigorous interactions among ARGs and abundant genera, suggesting that the host of ARGs potentially increased at low concentrations of SMX. Especially, genera g_norank_f__Beggiatoaceae, Ruminiclostridium, Caldicoprobacter, g_norank_o_MBA03, Hydrogenispora, and Ruminiclostridium_1 were major potential hosts for sul1. In conclusion, the rebounding of ARGs could be intermitted partially, and more efficient control of antibiotic resistance could be achieved in the thermophilic composting compared to conventional methods.

The fate of antibiotic resistance genes in cow manure composting: shaped by temperature-controlled composting stages

Current work for animal manure processing is not up to the required standards and hence are not supposed to reflect the actual performance in antibiotic resistance control. As a result, this study carried out temperature-controlled aerobic composting, with sulfamethoxazole (SMX) as a typical antibiotic. The results of four different treatments demonstrated that temperature, water content, C/N ratio, EC, and pH showed no significant (p > 0.05) difference. Antibiotic resistance genes (ARGs) significantly decreased in the initial 10 days of the thermophilic phase, but the abundance of sul1 and sul2 increased greatly after 30 days. Moreover, ARGs were closely related with each other during the late stages of composting. A noteworthy effect of composting properties, especially temperature on bacterial community, which then had a positive effect on ARGs abundances. These findings provided evidence that the standard composting was still insufficient to control antibiotic resistance.

Trace analysis of 28 antibiotics in plant tissues (root, stem, leaf and seed) by optimized QuEChERS pretreatment with UHPLC-MS/MS detection

Phytoremediation has proven to be an effective in-situ treatment technique for antibiotic contamination. Due to the immature methods of extracting multi-antibiotics in different plant tissues, the antibiotic absorption and transportation mechanism in the phytoremediation process has yet to be resolved. Therefore, an improved Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) pretreatment with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detection method for 28 antibiotics in different plant tissues (root, stem, leaf and seed) was developed in this study. The optimized method showed satisfactory performance with recoveries for most antibiotics ranging from 70% to 130% (except sulfadoxine with 138 ± 8.84% in root, sulfameter with 68.9 ± 1.87% and sulfadoxine with 141 ± 10.0% in seed). The limits of detection (LODs) of the target compounds in root, stem, leaf and seed were 0.04 ± 0.02 ~ 2.50 ± 1.14 ng/g, 0.05 ± 0.02 ~ 1.78 ± 0.42 ng/g, 0.06 ± 0.01 ~ 2.50 ± 0.14 ng/g and 0.13 ± 0.10 ~ 3.64 ± 0.74 ng/g, respectively. This developed method was successfully applied to the determination of antibiotics in different tissues of hydroponic wetland plants exposed to antibiotics-spiked water for one-month. Sixteen of 28 spiked antibiotics were detected in plant tissue samples. Overall, of these 16 antibiotics, all were detected in root samples (from < LOQ to 1478 ± 353 ng/g), eleven in stem samples (from < LOQ to 425 ± 47.0 ng/g), and nine in leaf samples (from < LOQ to 429 ± 84.5 ng/g). This developed analytical method provided a robust tool for the simultaneous screening and determination of antibiotics in different plant tissues.

Freeze-thaw approach: A practical sample preparation strategy for residue analysis of multi-class veterinary drugs in chicken muscle

Seven drugs from different classes, namely, fluoroquinolones (enrofloxacin, ciprofloxacin, sarafloxacin), sulfonamides (sulfadimidine, sulfamonomethoxine), and macrolides (tilmicosin, tylosin), were used as test compounds in chickens by oral administration, a simple extraction step after cryogenic freezing might allow the effective extraction of multi-class veterinary drug residues from minced chicken muscles by mix vortexing. On basis of the optimized freeze-thaw approach, a convenient, selective, and reproducible liquid chromatography with tandem mass spectrometry method was developed. At three spiking levels in blank chicken and medicated chicken muscles, average recoveries of the analytes were in the range of 71-106 and 63-119%, respectively. All the relative standard deviations were <20%. The limits of quantification of analytes were 0.2-5.0 ng/g. Regardless of the chicken levels, there were no significant differences (P > 0.05) in the average contents of almost any of the analytes in medicated chickens between this method and specific methods in the literature for the determination of specific analytes. Finally, the developed method was successfully extended to the monitoring of residues of 55 common veterinary drugs in food animal muscles.