Influence of filtration during sample pretreatment on the detection of antibiotics and non-steroidal anti-inflammatory drugs in natural surface waters

Determination of synthetic hallucinogens in oral fluids by microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry

A fast and simple procedure based on microextraction by packed sorbent (MEPS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the simultaneous quantification of 28 synthetic hallucinogens in oral fluids, including lysergic acid diethylamide and substances from NBOMe, NBOH, NBF, 2C, and substituted amphetamine categories. Extraction conditions such as type of sorbent, sample pH, number of charge/discharge cycles, and elution volume were studied. Hallucinogenic compounds were extracted from oral fluid samples using C18 MEPS, loading with 100 μL sample (adjusted to pH 7) in 3 cycles, washing with 100 μL deionized water, and eluting with 50 μL methanol in 1 cycle, giving quantitative recoveries and no significant matrix effects. Limits of detection from 0.09 to 1.22 μg L^-1; recoveries from 80 to 129% performed in spiked oral fluid samples at 20, 50, and 100 μg L^-1; and high precision with relative standard deviations lower than 9% were obtained. The proposed methodology was demonstrated to be appropriate for the simple and sensitive determination of NBOMe derivates and other synthetic hallucinogenic substances in oral fluid samples.

Fate and ecological risks of antibiotics in water-sediment systems with cultivated and wild Phragmites australis in a typical Chinese shallow lake

River carrying antibiotics from upstream posed serious threats to receiving lake, and plants might had effects on antibiotics. Therefore, samples of waters, sediments and tissues of cultivated and wild Phragmites australis were collected to analyse antibiotics fate and ecological risks (RQs) in Zaozhadian Lake. Our results revealed that the total antibiotics showed an increasing tendency in surface/pore water and P. australis tissues and a decreasing tendency in overlying water and sediments from the lake entrance to the centre. The bioaccumulation factors (BAFs) of two sulfonamides (SAs) and three quinolones (QNs) increased in sediments and decreased in those of erythromycin in pore water from Site 1 to Site 11. Three QNs and two tetracyclines (TCs) were dominant antibiotics in pore water/sediment and surface/overlying water respectively. Higher levels of two SAs in surface/pore water and two macrolides (MAs) in overlying/pore water and sediments were observed in the wild P. australis region, while higher values of two TCs in overlying/pore water and three QNs in sediment were observed in the cultivated P. australis region. Higher BAFs of SAs and QNs in sediments were observed in the cultivated and wild P. australis region respectively. The RQs of oxytetracycline and two MAs posed moderate risks in surface/overlying water from more than 50% of sampling sites. Norfloxacin exhibited moderate RQ and low ∑RQ levels in sediments, and showed high risk in pore water. Our findings imply that much more attention should be given to the antibiotics from river inputs and management normatives to control antibiotic pollution.

Comparison of sorption models to predict analyte loss during sample filtration and evaluation of the impact of filtration on data quality

Although filtration has been a widely applied sample pretreatment step in environmental analytical chemistry, its impact on the quality of the data produced is often underappreciated in the scientific community. The objective of this literature review and modeling exercise was to examine nine existing sorption models with input parameters including hydrophobic interactions, pH, and structural features to predict the loss of analytes during wastewater filtration due to sorption to suspended solids and to assess the impact of filtration on data quality. Models' sorption estimates were further validated with a set of comprehensive metadata collected and analyzed from 20 peer-reviewed research papers that reported physical measurements of the suspended solids sorbed fraction of analytes obtained during wastewater filtration of contaminants of emerging concern (CECs). Data on the impact of filtration were obtained from the literature for 156 organic compounds reported both for the dissolved and particulate bound analyte mass. Approximately 40% of CECs (62/156) showed significant filtration loss (>20%) as a result of the removal of suspended solids during filtration. The loss of analyte mass due to filtration ranged from <1% for atenolol to >95% for acenaphthene. Collected literature data were then used to evaluate the utility of sorption modeling to predict analyte losses during sample pretreatment. Among nine sorption models, three were found to predict filtration loss of at least 70% of the CECs evaluated within a range of ±20% of the actually measured filtration loss of analytes, assuming a suspended solid concentration of 200 mg/L and a fraction of organic carbon in suspended solids of 0.43. Thus, sorption modeling can help reduce error when calculating mass loadings based on samples filtered before analysis. It is concluded that the estimates could be further improved by considering the following factors: ionic interactions, characteristics of the water-borne sorbents, and filtration media properties.

A HPLC-MS/MS method for screening of selected antibiotic adulterants in herbal drugs

The use of herbal products adulterated with conventional drugs increases the risk of developing microbial resistance and causes herb-to-drug interaction, leading to severe clinical consequences. The complex nature of herbal products has been a challenge for the unambiguous identification of adulterants. The improved analytical selectivity and sensitivity of hyphenated techniques such as high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) enable the confirmatory screening of adulterants in herbal products. Simultaneous screening of adulterants is necessary and efficient because it has been established that more than one chemical adulterant may be present in one herbal product. An HPLC-MS/MS method for the simultaneous detection and quantification of amoxicillin, ampicillin, metronidazole, ciprofloxacin, sulfamethoxazole, and trimethoprim in powdered herbal drugs was developed. Deuterated metronidazole-d3, trimethoprim-d3, ciprofloxacin-d8, and sulfamethoxazole-d4 were used as internal standards (ISs). For each analyte, two transitions were monitored using protonated molecules as precursor ions. The extraction of analytes from herbal products was performed using a simple methanol : water : formic acid (90 : 10 : 0.05, v/v) extraction solvent. Chromatographic separation was done in a gradient of 0.01% formic acid in methanol and 0.01% formic acid in MilliQ water. The calibration curves were linear (r² ≥ 0.996) over the range of 0.005-2.5 μg mL^-1 for all compounds except metronidazole, whose range was 0.005-1 μg mL^-1. The limit of detection (LOD) ranged from 0.012 to 0.046 μg mL^-1, while the limit of quantification (LOQ) ranged from 0.066 to 0.153 μg mL^-1. The accuracy, expressed as the recovery of spiked herbal products, ranged from 45% to 114%. The precision, expressed as relative standard deviation (RSD) at two concentration levels, ranged from 1.6% to 15.9%. The matrix effect expressed as the matrix factor (MF) ranged from 0.79 to 0.92. The developed method was applied to powder herbal products purchased in Tanzania. Amoxicillin, ampicillin, trimethoprim, sulfamethoxazole, and ciprofloxacin were not detected in all samples. Metronidazole was detected in eight samples with the highest concentration of 1.38 μg g^-1. The developed method is suitable for the detection of all the studied antibiotic adulterants in herbal products. Quantification can be performed for all the compounds except ciprofloxacin due to its lower recovery.

Occurrence and fate of pharmaceuticals, personal care products (PPCPs) and pesticides in African water systems: A need for timely intervention

The occurrence of emerging contaminants (ECs) such as pharmaceuticals, personal care products (PPCPs) and pesticides in the aquatic environment has raised serious concerns about their adverse effects on aquatic species and humans. Because of their toxicity and bioactive nature, PPCPs and pesticides have more potential to impair water systems than any other contaminants, causing several adverse effects, including antibiotic resistance, reproductive impairment, biomagnification, bioaccumulation, etc. Over 35 publications from Africa have reported on the occurrence and fate of PPCPs and pesticides in African water systems with little or no data on remediation and control. As a result, adequate intervention strategies are needed for regulating the persistence of PPCPs and pesticides in African water systems.

Low-temperature partitioning extraction followed by liquid chromatography tandem mass spectrometry determination of multiclass antibiotics in solid and soluble wastewater fractions

An analytical method based on low-temperature partitioning extraction (LTPE) followed by high performance liquid chromatography coupled to triple quadrupole mass spectrometry analysis was developed and validated for the determination of eight multiclass antibiotics in wastewater. The analyzed target antibiotics included one β-lactam, two sulfonamides, three fluoroquinolones, one macrolide and one diaminopyrimidine. LTPE parameters such as sample pH, volume ratio between sample and extractor solvent, ultra-sonic extraction time, extraction tube material, solvent and volume to reconstitute the sample extracts, were optimized. Additionally, the influence of solids on extraction efficiency was evaluated. Quantification of the target antibiotics was performed by double consecutive injection method, without the use of a labeled compound, in order to correct matrix effects. The whole samples were analyzed, including, liquid and solid fractions of wastewater. The results revealed that the filtration step can underestimate the total antibiotics concentration, particularly to the hydrophobic compounds that have higher affinity for solids, indicating that the suspended wastewater particulate should not be neglected. The method detection limit ranged from 18.54 ng L^-1 (trimethoprim) to 78.49 ng L^-1 (ciprofloxacin). Intra-day precision of less than 12.3% was achieved. The recoveries values ranged from 13.9% (sulfadiazine) to 48.9% (erythromycin) in influent samples and from 19.1% (sulfadiazine) to 57.2% (ciprofloxacin) in effluent samples. The method was applied to the measurement of antibiotic residues in influent and effluent from wastewater treatment plants. The majority target antibiotics were detected in wastewater samples. Their concentrations ranged from 237 to 9553 ng L^-1 in influent and from 212 to 1660 ng L^-1 in effluent. This work provides new insights on the applicability of LTPE for antibiotic residues extraction from wastewater. In addition, the performed analysis highlights the importance of measuring total concentrations of analytes in whole sample.

Sample Preparation to Determine Pharmaceutical and Personal Care Products in an All-Water Matrix: Solid Phase Extraction

Pharmaceuticals and personal care products (PPCPs) are abundantly used by people, and some of them are excreted unaltered or as metabolites through urine, with the sewage being the most important source to their release to the environment. These compounds are in almost all types of water (wastewater, surface water, groundwater, etc.) at concentrations ranging from ng/L to µg/L. The isolation and concentration of the PPCPs from water achieves the appropriate sensitivity. This step is mostly based on solid-phase extraction (SPE) but also includes other approaches (dispersive liquid-liquid microextraction (DLLME), buckypaper, SPE using multicartridges, etc.). In this review article, we aim to discuss the procedures employed to extract PPCPs from any type of water sample prior to their determination via an instrumental analytical technique. Furthermore, we put forward not only the merits of the different methods available but also a number of inconsistencies, divergences, weaknesses and disadvantages of the procedures found in literature, as well as the systems proposed to overcome them and to improve the methodology. Environmental applications of the developed techniques are also discussed. The pressing need for new analytical innovations, emerging trends and future prospects was also considered.

Selected antibiotics and current-use pesticides in riverine runoff of an urbanized river system in association with anthropogenic stresses

Antibiotics and current-use pesticides are ubiquitous in the environment. It is important to figure out their spatial distribution under the influences of anthropogenic activities and transport from rivers to coastal oceans. To address this knowledge gap, the present study conducted quarterly sampling in eight main runoff outlets of the Pearl River, South China, and obtained total concentrations of antibiotics and current-use pesticides at 24-296 ng L^-1. Higher total concentrations of these chemicals occurred in summer, attributed to seasonal consumption patterns and washout by rainfalls, respectively. The spatial distributions of target analytes were not significantly different between the eastern and western outlets with high and moderate urbanization levels, respectively. Approximately 16.4, 17.7, and 12.5 tons of antibiotics, organophosphorus pesticides, and neonicotinoids were discharged annually from the outlets to the South China Sea. These results suggested that usage amount and hydrology exhibited positive effects on the riverine inputs of the target chemicals. In addition, most target chemicals exhibited low risks to green algae, but erythromycin and parathion posed high ecological risks to aquatic organism (Daphnid and fish).

Distribution, residue level, sources, and phase partition of antibiotics in surface sediments from the inland river: a case study of the Xiangjiang River, south-central China

In view of the increasing attention on antibiotic contamination and their scarce data in the inland river (especially for the sediment), the occurrence of 28 antibiotics in sediments from the Xiangjiang River was comprehensively analyzed, and 22 antibiotics were detected with a total concentration ranging from 4.07 to 2090 ng g^-1. The residue was almost at a moderate or higher level in the aquatic environment around the world. Fluoroquinolones and tetracyclines were the dominant detected antibiotics, and the maximum total concentration could reach to 2085 ng g^-1, though that in surface water was just 33.4 ng L^-1. Oxytetracycline and chlortetracycline could be detected with high concentration in areas with lower population density. Usage profile of each antibiotic may be responsible for the spatial variation. Principal component analysis-multiple linear regression model indicated that direct discharge of domestic wastewater and livestock or aquaculture sewage could contribute 94.2% of the pollution. Redundancy analysis was used to screen out the environment variables, which were closely related to the pseudo-partitioning coefficients (K_d) of antibiotics in sediment and surface water for the first time, and showed that the K_d was correlated with sediment pH negatively and organic carbon, total phosphorus, and conductivity of the sediments positively. High sedimentary organic carbon was considered to promote the higher K_d in this river. This study would deepen the understanding of the occurrence of antibiotics in sediments from the inland rivers and provide scientific support for controlling the antibiotic contamination.

Editorial of the VSI "Antibiotics and heavy metals in the environment: Facing the challenge"

The Virtual Special Issue (VSI) "Antibiotics and Heavy Metals in the Environment: Facing the Challenge" received more than 100 submissions from research teams around the world. Finally, more than 50 papers were accepted and published. These very interesting research papers allow going ahead in the knowledge of different aspects which determine the fate of antibiotics and heavy metals in the environmental. The success of the VSI, as well as reports from scientific databases, indicate that this field of research is clearly growing, which is expected to continue, especially considering emerging pollutants as a whole.