LC–MS2 for quantifying trace amounts of pharmaceutical compounds in soil and sediment matrices

Antibiotic pollution of the Yellow River in China and its relationship with dissolved organic matter: Distribution and Source identification

Understanding the sources of antibiotics is important for managing antibiotic contamination and preventing environmental risks in the aquatic environment. In this study, the distribution of dissolved organic matter (DOM) and 24 antibiotics from four typical classes (quinolones, macrolides, sulfonamides and tetracyclines) in the Yellow River basin containing distinct sources of pollution was investigated. In particular, relationships between the antibiotic concentrations and fluorescent properties of DOM were to be established to identify antibiotic sources. A total of 22 antibiotics were detected, with maximum concentrations ranging from 0.27 to 30.14 ng/L in the mainstream of the Yellow River. Of these antibiotics, only erythromycin (ERY) and sulfamethoxazole (SMX) posed potential risks to aquatic organisms. Spatially, tetracyclines were mainly distributed in the upstream reaches of the river, and quinolones were largely distributed in the midstream. High levels of sulfonamides were present downstream of the investigated river. Only EYR belonging to the macrolide group was detected and had a high downstream concentration. EEM-PARAFAC analysis showed that DOM was composed of visible fulvic acid-like fluorescence fraction (C1), ultraviolet fulvic acid-like fluorescence fraction (C2) and protein-like fraction (C3). Using Pearson correlation analysis, this study demonstrated a close relationship between DOM spectral parameters and antibiotic concentrations in the Yellow River basin. Specifically, r (C3, C2) was significantly and positively correlated with the concentrations of SMX, sulfadoxine (SDX), and ERY, while humification index (HIX) had an opposite relationship with these antibiotics. These results suggested that SMX, SDX and ERY were mainly discharged from wastewater treatment plants into the mainstream of the Yellow River. This work provides a powerful demonstration that DOM plays an important role in indicating the occurrence and sources of antibiotics in the aquatic environment.

Occurrence, Distribution, and Risk Assessment of Antibiotics in the Aquatic Environment of the Karst Plateau Wetland of Yangtze River Basin, Southwestern China

In this study, the occurrence, distribution, and ecological risk of 40 commonly used antibiotics, including 15 sulfonamides (SAs), 9 fluoroquinolones (FQs), 7 macrolides (MCs), 3 tetracyclines (TCs), 2 chloramphenicols (CAPs), and 4 other categories, in the aquatic environment of the karst plateau wetland Caohai of the Yangtze River basin in southwestern China are reported. In total, 27 antibiotics were detected, with the detection rate ranging from 5% to 100%. The total concentration at each site ranged from 21.8 ng/L to 954 ng/L, with the average concentration being 189 ng/L. FQs and MCs were the most predominant categories, contributing 29.3% and 25.0% of the total antibiotic burden. The five most commonly detected antibiotics were ciprofloxacin (CIP), oxytetracycline (OTC), acetyl sulfamethoxazole (ASMZ), norfloxacin (NOR), and florfenicol (FF). The spatial distribution of the total concentration at each site demonstrated a decreasing trend from the southeastern area upstream adjoining the main counties to the northwestern area downstream, indicating that human activities have a great impact. Meanwhile, the natural attenuation rates of different types of antibiotics in the direction of flow ranged from 17.6% to 100%, which implied the natural purification potential of the wetland for antibiotics. The cluster analysis results indicated that domestic sewage and wastewater from agriculture and animal husbandry were the main sources of contamination in the surrounding wetland. Risk quotients (RQs) assessment showed that most of the individuals were at low to medium risk and that the adverse risks posed by mixtures of antibiotics were higher than those posed by the individual antibiotics.

Determination of 38 antibiotics in raw and treated wastewater from swine farms using liquid chromatography-mass spectrometry

The present study firstly aimed at developing a multi-residue method to identify and quantify 38 veterinary antibiotics (belonging to 5 different classes) not only for raw swine wastewater but also for wastewater different treated by different units. The proposed method is based on a solid-phase extraction procedure and ultra-performance liquid chromatography with mass spectrometry. For sample preparation, the optimal loading sample volume was selected as 50 mL, whose pH was adjusted to approximately 3.0 using formic acid. Then 0.1 g/L ethylenediamine tetraacetic acid disodium salt was added. The recovery rates for different types of wastewaters were in the range of 35.94%-124.51% and the relative standard deviations were in the range of 0.36%-14.62%. All the matrix standard curves exhibited high linearity (0.9956-0.9999). The matrix effects for the target antibiotics ranged from -61.73% to +148.75%. To ensure practicality of the method, we performed the detection of the actual added concentration to determine method detection limits and quantitation limits. The quantitation limits of most of the target antibiotics were 0.04 μg/L, except for spiramycin (0.1 μg/L) and roxithromycin (0.2 μg/L). This optimized and validated method was applied to analyze antibiotic residues in swine water samples from 4 swine farms. This article is protected by copyright. All rights reserved.

Predicting the trend and utility of different photocatalysts for degradation of pharmaceutically active compounds: A special emphasis on photocatalytic materials, modifications, and performance comparison

The rapid rise in the healthcare sector has led to an increase in pharmaceutically active compounds (PhACs) in different aqueous bodies. The toxicity of the PhACs and their ability to persist after conventional treatment processes have escalated research in the field of photocatalytic treatment. Although different photocatalysts have been successful in degrading PhACs, their inherent drawbacks have severely limited their application on a large scale. A substantial amount of research has been aimed at overcoming the high cost of the photocatalytic material, low quantum yield, the formation of toxic end products, etc. Hence, to further research in this field, researchers must have a fair idea of the current trends in the application of different photocatalysts. In this article, the trends in the use of various photocatalysts for the removal of different PhACs have been circumscribed. The performance of different groups of photocatalysts to degrade PhACs from synthetic and real wastewater has been addressed. The drawbacks and advantages of these materials have been compared, and their future in the field of PhACs removal has been predicted using S-curve analysis. Zinc and titanium-based photocatalysts were efficient under UV irradiation, while bismuth and graphene-based materials exhibited exemplary performance in visible light. However, iron-based compounds were found to have the most promising future, which may be because of their magnetic properties, easy availability, low bandgap, etc. Different modification techniques, such as morphology modification, doping, heterojunction formation, etc., have also been discussed. This study may help researchers to clarify the current research status in the field of photocatalytic treatment of PhACs and provide valuable information for future research.

New parameters for the quantitative assessment of the proliferation of antibiotic resistance genes dynamic in the environment and its application: A case of sulfonamides and sulfonamide resistance genes

Antibiotic resistance genes (ARGs) have been widely detected around the world and are generally viewed as emerging pollutants with environmental persistence. The proliferation of ARGs can be easily promoted by antibiotics. However, the dynamics of ARGs in the environment are still unable to be quantified using a single parameter, which is vital to evaluating the ability of ARGs to spread by antibiotics and effectively controlling ARGs. A new parameter, termed the relative area ratio of sample to control (ΔA^R), was developed based on the quantitative features determined by ARG-time curves in soils contaminated with sulfonamides (SAs) and verified by quantitative structure-activity relationships (QSARs) models. The results showed that ΔA^R can not only be used to accurately quantify the characteristics of SAs resistance genes (Suls) over time but also be applied to reveal the relationships between the proliferation of Suls and important factors (i.e., concentrations and chemical structures). Moreover, the ΔA^R-based QSARs model indicated that bioavailability and the frequency of conjugative transfer, rather than the ability of induced mutations in bacteria, tend to be key processes of the characteristics of the proliferation of Suls. Therefore, ΔA^R is a useful parameter to perform environmental risk assessments of ARG proliferation in the environment.

Occurrence of endocrine disrupting compounds in mariculture sediment of Pulau Kukup, Johor, Malaysia

Endocrine-disrupting compounds (EDCs) such as hormones, pesticides, phenolic compounds, and pharmaceuticals compounds can cause adverse effects on humans, animals, and other living organisms. One of the largest mariculture areas situated in Pulau Kukup, Johor, Malaysia, is actively involved in exporting marine fish to other countries worldwide. This paper aims to provide baseline data on the level of EDC pollutants found in mariculture sediments in Malaysia since no reports have investigated this issue. Calculated samples recovered are between 50.39 and 129.10% at 100 ng/g spiking level. The highest concentration in the sediment samples was bisphenol A (0.072-0.389 ng/g dry weight) followed by diethylstilbestrol (<0.208-0.331 ng/g dry weight) and propranolol (<0.250-0.275 ng/g dry weight). Even though the concentrations of the targeted compounds obtained were low, their effects could become more evident longer term, which raises not only environmental health concerns but the potential risk to humans.

Cytostatic pharmaceuticals as water contaminants

Due to the growing problem of cancer diseases, cytostatic drugs have become a great environmental threat. Their main sources are hospital effluents, household discharge and drug manufacturers. As these compounds are not removed during wastewater treatment with sufficient efficiency, they are found in the surface, ground and drinking water in quantities up to 2.12 × 10^-4 mg/l. The current knowledge about their harmful influence on humans does not indicate a significant risk to the health of water consumers, although it points to certain groups of risk (children and lactating women) in particular. In aquatic organisms, anticancer drugs in detected concentrations can cause chronic toxicity and have a detrimental impact on their genetic material. The acute toxicity effect is less likely. The HC₅ value calculated by us (the concentration at which 5% of the species is potentially affected) equalling 2.1 × 10^-4 mg/l shows that anticancer drugs are real hazardous contaminants for the environment. It indicates that effective elimination of cytostatics from water still requires intensive research.

Occurrence and seasonal variations of 25 pharmaceutical residues in wastewater and drinking water treatment plants

Thousands of tons of pharmaceuticals are introduced into the aqueous environment due to their incomplete elimination during treatment process in wastewater treatment plants (WWTPs) and water treatment plants (WTPs). The presence of pharmacologically active compounds in the environment is of a great interest because of their potential to cause negative effects. Furthermore, drugs can undergo different processes leading to the formation of new transformation products, which may be more toxic than the parent compound. In light of these concerns, within the research a new, rapid and sensitive analytical procedure for the determination of a wide range of pharmaceuticals from different classes using solid phase extraction (SPE) and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) technique in different water samples was developed. This methodology was applied to investigate the occurrence, removal efficiency of 25 pharmaceuticals during wastewater and drinking water treatment, and seasonal variability in the amount of selected pharmaceuticals in WWTP and WTP over a year. The most often detected analytes in water samples were carbamazepine (100 % of samples) and ibuprofen (98 % of samples), concluding that they may be considered as pollution indicators of the aqueous environment in tested area. Highly polar compound, metformin, was determined at very high concentration level of up to 8100 ng/L in analyzed water samples. Drugs concentrations were much higher in winter season, especially for non-steroidal inflammatory drugs (NSAIDs) and caffeine, probably due to the inhibited degradation related to lower temperatures and limited sunlight. Carbamazepine was found to be the most resistant drug to environmental degradation and its concentrations were at similar levels during four seasons.

Co-occurrence of musk fragrances and UV-filters in seafood and macroalgae collected in European hotspots

In the last decades, awareness regarding personal care products (PCP), i.e. synthetic organic chemicals frequently used in cosmetic and hygienic products, has become a forward-looking issue, due to their persistency in the environment and their potential multi-organ toxicity in both human and wildlife. Seafood is one of the most significant food commodities in the world and, certainly, one of the most prone to bioaccumulation of PCP, what can consequently lead to human exposure, especially for coastal population, where its consumption is more marked. The aim of this work was to evaluate the co-occurrence of musk fragrances and UV-filters in both seafood and macroalgae collected in different European hotspots (areas with high levels of pollution, highly populated and near wastewater treatment plants). Despite the fact that UV-filters were detected in three different kind of samples (mussel, mullet, and clam), in all cases they were below the limit of quantification. Galaxolide (HHCB) and tonalide (AHTN) were the musk fragrances most frequently detected and quantified in samples from the European hotspots. Cashmeran (DPMI) was also detected in most samples but only quantified in two of them (flounder/herring and mullet). The highest levels of HHCB and AHTN were found in mussels from Po estuary.

Acute toxicological effects on the earthworm Eisenia fetida of 18 common pharmaceuticals in artificial soil

Following soil applications of recycled water and biosolids, pharmaceutical residues can eventually enter the terrestrial environment. In vitro and in vivo assays have largely focused on the acute ecotoxicity of these compounds in aquatic systems. However, studies on the ecotoxicological effects of pharmaceuticals in soil biota are especially scarce. The aim of this study was to investigate the acute toxicity of 18 pharmaceuticals (4 NSAIDs, 5 blood lipid-lowering agents, 6 β-blockers and 3 antibiotics) that are usually found in the environment by using an Eisenia fetida bioassay. In addition, the presence of these pharmaceuticals in artificial soil was verified at the end of the test. Our results indicate that seven of the studied drugs cause acute adverse effects in E. fetida, in particular, the NSAIDs and the blood lipid-lowering agents. Ibuprofen (LC50=64.80 mg/kg) caused the highest acute toxicity for all tested compounds, followed by diclofenac (LC50=90.49 mg/kg) and simvastatin (LC50=92.70 mg/kg). Other tested pharmaceuticals from NSAIDs and blood lipid-lowering families have toxicity effects, from a LC50=140.87 mg/kg for gemfibrozil to 795.07 mg/kg for lovastatin. Atorvastatin, bezafibrate, β-blockers and antibiotics showed no detectable lethality in E. fetida. The four NSAIDs showed evidence of modification of their original chemical structure after 14 days so the detected toxicity may be due to the original product as well as their degradation products. The three blood lipid-lowering agents seem to be more stable in soil. From an environmental perspective, the lethal concentrations of the tested drugs are much greater than those reported in wastewater and biosolids, therefore acute toxic effects may be improbable. However, little is known about the accumulation of these substances in soils after regular applications, so accumulative and chronic effects cannot be excluded. Moreover, more studies are needed to determine the role of the degradation products of these pharmaceuticals on terrestrial toxicity.

Transformation products of antibiotic and cytostatic drugs in the aquatic cycle that result from effluent treatment and abiotic/biotic reactions in the environment: an increasing challenge calling for higher emphasis on measures at the beginning of the pipe

Pharmaceuticals may undergo transformation into new products during almost all possible processes along their life-cycle. This could either take place in the natural water environment and/or during water treatment processes. Numerous studies that address the issue of such transformation products (TPs) have been published, describing selected aspects of TPs in the environment and their formation within effluent and water treatment processes. In order to exemplify the number and quality of information published on TPs, we selected 21 active pharmaceutical ingredients from the groups of antibiotics and antineoplastics, and assessed the knowledge about their TPs that has been published until the end of May 2012. The goal of this work was to demonstrate, that the quality of data on pharmaceutical TPs greatly differs in terms of the availability of chemical structures for each TP, rather than to provide an exhaustive database of available TPs. The aim was to point out the challenge going along with so many TPs formed under different treatment and environmental conditions. An extensive review in the form of a table showing the existing data on 158 TPs for 15 compounds, out of 21 investigated, was presented. Numerous TPs are the result of different treatments and environmental processes. However, also numerous different TPs may be formed within only one type of treatment, applied under sometimes even very similar treatment conditions and treatments times. In general, the growing number of elucidated TPs is rationalized by ineffective removal treatments. Our results demonstrate a severe risk of drowning in much unrelated and non-assessable data, both from a scientific and from a technical treatment-related point of view. Therefore, limiting the input of pharmaceuticals into effluents as well as improving their (bio) degradability and elimination behavior, instead of only relying on advanced effluent treatments, is urgently needed. Solutions that focus on this "beginning of the pipe" approach should minimize the adverse effects of parent compounds by reducing and formation of TPs and their entrance into the natural environment.

Monitoring Antibiotic Residues and Corresponding Antibiotic Resistance Genes in an Agroecosystem

Antibiotic resistance genes (ARGs) have been commonly reported due to the overuse worldwide of antibiotics. Antibiotic overuse disturbs the environment and threatens public human health. The objective of this study was to measure the residual concentrations of veterinary antibiotics in the tetracycline group (TCs), including tetracycline (TC) and chlortetracycline (CTC), as well as those in the sulfonamide group (SAs), including sulfamethazine (SMT), sulfamethoxazole (SMX), and sulfathiazole (STZ). We also isolated the corresponding ARGs in the agroecosystem. Four sediment samples and two rice paddy soil samples were collected from sites near a swine composting facility along the Naerincheon River in Hongcheon, Korea. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed with a solid-phase extraction method to measure the concentration of each antibiotic. ARGs were identified by the qualitative polymerase chain-reaction using synthetic primers. SAs and their corresponding ARGs were highly detected in sediment samples whereas TCs were not detected except for sediments sample #1. ARGs for TCs and SAs were detected in rice paddy soils, while ARGs for TCs were only found in sediment #2 and #4. Continuous monitoring of antibiotic residue and its comprehensive impact on the environment is needed to ensure environmental health.

The sorption of sulfamethazine on soil samples: isotherms and error analysis

In this paper, batch sorption of sulfamethazine on eight soil samples (six from Croatia and two from Bosnia and Hercegovina) with different organic matter contents ranging from 1.52 to 12.8% was investigated. The effects of various parameters such as agitation time, initial concentration, and ionic strength on the sulfamethazine sorption were studied. The experimental data were analysed using a one-parameter model, Linear isotherm, and two two-parameter models, the Freundlich and Dubinin-Radushkevich isotherms. The goodness of fit was measured using the linear regression and the determination coefficient (R(2)) value. Also, the equilibrium data of the two-parameter models were analysed using the residual root mean square error (RMSE), the sum of squares of errors (ERRSQ), and a composite fractional error function (HYBRID). Non-linear regression has better characteristics for analysing experimental data. The obtained sorption coefficients Kd (from 0.25 to 8.10 mL/g) and the Freundlich sorption coefficients KF (from 1.16 to 7.99 (μg/g)(mL/μg)(1/n)) exhibited quite low values, which indicated that sulfamethazine is weakly adsorbed on the evaluated soils, is highly mobile, and has a great potential to penetrate and pollute the ground water. The Dubinin-Radushkevich isotherm was used to estimate the apparent free energy of sorption.

Occurrence, distribution and bioaccumulation of antibiotics in the Liao River Basin in China

The occurrence and distribution of 19 antibiotics including ten sulfonamides, four quinolones, three tetracyclines and two macrolides in water, sediment, and biota samples from the Liao River Basin, China were investigated in the present study. The samples were collected in May 2012, and laboratory analyses revealed that antibiotics were widely distributed in the Liao River Basin. Macrolides made up the majority of antibiotics in the water ranging from not detected (ND) to 3162.22 ng L(-1), while tetracyclines and macrolides were the predominant antibiotics in the sediments, ranging from ND to 404.82 μg kg(-1) (mean 32.11 μg kg(-1) dw) and ND to 375.13 (mean 32.77 μg kg(-1) dw), with detection frequencies of 37.3% and 38.1%, respectively. In biological samples, quinolones were the most frequently detected antibiotics (57.1-100%), with concentrations ranging from 286.6-1655.3 μg kg(-1). The highest bioaccumulation factor (BAF) of 45407 L kg(-1) was found for enrofloxacin. The phase distribution calculation showed that tetracyclines were the most strongly adsorbed antibiotics in the sediment, with the highest pseudo-partitioning coefficient values, ranging from 1299 to 1499 L kg(-1). The geographical differences of antibiotic concentrations were largely due to anthropogenic activities and the sewage discharges from the local cities along the rivers.

Occurrence of antibiotics in water, sediments, aquatic plants, and animals from Baiyangdian Lake in North China

This study investigated the presence and distribution of 22 antibiotics, including eight quinolones, nine sulfonamides and five macrolides, in the water, sediments, and biota samples from Baiyangdian Lake, China. A total of 132 samples were collected in 2008 and 2010, and laboratory analyses revealed that antibiotics were widely distributed in the lake. Sulfonamides were the dominant antibiotics in the water (0.86-1563 ng L(-1)), while quinolones were prominent in sediments (65.5-1166 μg kg(-1)) and aquatic plants (8.37-6532 μg kg(-1)). Quinolones (17.8-167 μg kg(-1)) and macrolides [from below detection limit (BDL) to 182 μg kg(-1)] were often found in aquatic animals and birds. Salvinia natans exhibited the highest bioaccumulation capability for quinolones among three species of aquatic plants. Geographical differences of antibiotic concentrations were greatly due to anthropogenic activities. Sewage discharged from Baoding City was likely the main source of antibiotics in the lake. Risk assessment of antibiotics on aquatic organisms suggested that algae and aquatic plants might be at risk in surface water, while animals were likely not at risk.

Matrix effects and recovery calculations in analyses of pharmaceuticals based on the determination of β-blockers and β-agonists in environmental samples

In recent years substantial progress has been made in analytical methods for determining pharmaceutical residues in environmental samples. Although much work has attempted to establish the influence of sample matrix complexity on results through the determination of matrix effects (ME), extraction efficiency (EE) and absolute recovery of analytes (AR), comparison of these parameters is very complicated because different authors use different methods to obtain them. Moreover, there are few literature data describing the influence of aqueous matrices (tap water and waste water) on results obtained with GC-MS methods. For these reasons, the main aims of the present study were: (1) to critically review the determination of matrix effects and recovery parameters using the two most common techniques for analyzing drugs in environmental samples: gas and liquid chromatography coupled with mass spectrometry or tandem mass spectrometry (GC-MS, GC-MS/MS and LC-MS, LC-MS/MS); (2) to postulate a uniform method for determining ME, EE and AR using GC techniques; (3) to investigate the influence of different aqueous matrices on the solid-phase extraction, derivatization and final determination of drugs using GC. β-Blockers and β-agonists, drugs commonly found in the environment, were chosen as model compounds for this investigation. The values of ME, EE and AR obtained were compared with analogous (or similar) data obtained by other researchers using LC-MS measurements. All the results confirmed that GC-MS analyses are much less sensitive to the complexity of sample matrices than LC-MS, so GC-MS measurements appear to be a very good alternative to LC-MS methods of determining pharmaceutical residues in environmental samples.

Optimization of matrix solid-phase dispersion for liquid chromatography tandem mass spectrometry analysis of 12 pharmaceuticals in sediments

The matrix solid-phase dispersion (MSPD) technique accompanied with LC-MS/MS detection for the purpose of determination of 12 pharmaceuticals (sulfaguanidine, sulfadiazine, sulfamethazine, sulfamethoxazole, trimethoprim, roxithromycin, praziquantel, febantel, enrofloxacin, ciprofloxacin, norfloxacin and procaine) applied to sediment samples has been described in this paper. Different parameters, such as the type of solid phase, the elution solvent and its volume have been investigated. The analytes were successfully extracted by C18 as an MSPD sorbent with 5 mL of acetonitrile:5% of oxalic acid=6:4 (v/v) as an elution solvent. The proposed method provides a linear response over the concentration range of 0.0005-100 μg/g, depending on pharmaceuticals with correlation coefficients above 0.9928 in all cases except for trimethoprim (0.9889). Also, the method has revealed low limits of detection (0.125-500 ng/g), good precision (intra and inter-day), a relative standard deviation below 15% and recoveries above 80%, except for roxithromycin, febantel and enrofloxacin. The method has been successfully applied to analysis of different sediment samples.

Determination of selected antibiotics in the Istanbul strait sediments by solid-phase extraction and high performance liquid chromatography

Surface sediments from 12 different locations of the Istanbul Strait and Marmara Sea, Turkey were analysed for five antibiotics belonging to two different groups of widely used pharmaceuticals, tetracyclines (TCs) and fluoroquinolones (FQs), by solid-phase extraction and high performance liquid chromatography. These two groups of antibiotics, mainly used to prevent or treat illness for humans as well as for animals, are frequently detected in the effluent of municipal sewage plants, in the aquatic environments and in soils after being spread by liquid manure. The results of analysis revealed that measured concentrations of individual antibiotics were significantly different depending on sampling location. Chlortetracycline (CTC) was not detected in any of the samples. High concentrations were mainly found in urbanized regions of the Strait. The concentrations of the two tetracyclines ranged from not detectable to 27.3 μg kg(-1) in freeze-dried marine sediments. Comparable results were obtained for the two fluoroquinolones with concentration levels from 1.3 μg kg(-1) up 34.1 μg kg(-1). This study is the first attempt to show the contamination degree of the Istanbul Strait sediments by emerging contaminants. Particular concern should be given concerning their potential side effects caused by the frequent consumption of mussels and fishes captured in the Istanbul Strait.

Fragmentation of toxicologically relevant drugs in positive-ion liquid chromatography-tandem mass spectrometry

The identification of drugs and related compounds by LC-MS-MS is an important analytical challenge in several application areas, including clinical and forensic toxicology, doping control analysis, and environmental analysis. Although target-compound based analytical strategies are most frequently applied, at some point the information content of the MS-MS spectra becomes relevant. In this article, the positive-ion MS-MS spectra of a wide variety of drugs and related substances are discussed. Starting point was an MS-MS mass spectral library of toxicologically relevant compounds, available on the internet. The positive-ion MS-MS spectra of ∼570 compounds were interpreted by chemical and therapeutic class, thus involving a wide variety of drug compound classes, such benzodiazepines, beta-blockers, angiotensin-converting enzyme inhibitors, phenothiazines, dihydropyridine calcium channel blockers, diuretics, local anesthetics, vasodilators, as well as various subclasses of anti-diabetic, antidepressant, analgesic, and antihistaminic drugs. In addition, the scientific literature was searched for available MS-MS data of these compound classes and the interpretation thereof. The results of this elaborate study are presented in this article. For each individual compound class, the emphasis is on class-specific fragmentation, as discussing fragmentation of all individual compounds would take far too much space. The recognition of class-specific fragmentation may be quite informative in determining the compound class of a specific unknown, which may further help in the identification. In addition, knowledge on (class-specific) fragmentation may further help in the optimization of the selectivity in targeted analytical approaches of compounds of one particular class.

Nontarget analysis of polar contaminants in freshwater sediments influenced by pharmaceutical industry using ultra-high-pressure liquid chromatography-quadrupole time-of-flight mass spectrometry

A comprehensive analytical procedure for a reliable identification of nontarget polar contaminants in aquatic sediments was developed, based on the application of ultra-high-pressure liquid chromatography (UHPLC) coupled to hybrid quadrupole time-of-flight mass spectrometry (QTOFMS). The procedure was applied for the analysis of freshwater sediment that was highly impacted by wastewater discharges from the pharmaceutical industry. A number of different contaminants were successfully identified owing to the high mass accuracy of the QTOFMS system, used in combination with high chromatographic resolution of UHPLC. The major compounds, identified in investigated sediment, included a series of polypropylene glycols (n=3-16), alkylbenzene sulfonate and benzalkonium surfactants as well as a number of various pharmaceuticals (chlorthalidone, warfarin, terbinafine, torsemide, zolpidem and macrolide antibiotics). The particular advantage of the applied technique is its capability to detect less known pharmaceutical intermediates and/or transformation products, which have not been previously reported in freshwater sediments.

Fate of antibiotics during municipal water recycling treatment processes

Municipal water recycling processes are potential human and environmental exposure routes for low concentrations of persistent antibiotics. While the implications of such exposure scenarios are unknown, concerns have been raised regarding the possibility that continuous discharge of antibiotics to the environment may facilitate the development or proliferation of resistant strains of bacteria. As potable and non-potable water recycling schemes are continuously developed, it is imperative to improve our understanding of the fate of antibiotics during conventional and advanced wastewater treatment processes leading to high-quality water reclamation. This review collates existing knowledge with the aim of providing new insight to the influence of a wide range of treatment processes to the ultimate fate of antibiotics during conventional and advanced wastewater treatment. Although conventional biological wastewater treatment processes are effective for the removal of some antibiotics, many have been reported to occur at 10-1000 ng L(-1) concentrations in secondary treated effluents. These include beta-lactams, sulfonamides, trimethoprim, macrolides, fluoroquinolones, and tetracyclines. Tertiary and advanced treatment processes may be required to fully manage environmental and human exposure to these contaminants in water recycling schemes. The effectiveness of a range of processes including tertiary media filtration, ozonation, chlorination, UV irradiation, activated carbon adsorption, and NF/RO filtration has been reviewed and, where possible, semi-quantitative estimations of antibiotics removals have been provided.

Determination of veterinary pharmaceuticals in poultry litter and soil by methanol extraction and liquid chromatography-tandem mass spectrometry

Pharmaceuticals are emerging contaminants with potential risks to the environment and human health. A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed for determination of the antimicrobials virginiamycin, monensin, salinomycin, narasin and nicarbazin in poultry litter and soil. This method involves methanol extraction and clean-up of extracts through glass microfibre filters, introduction of the extracts and separation of compounds on a Zorbax Eclipse XDB C8 column, and compound detection in a Quattro Micro Micromass spectrometer. For litter samples, Method Detection Limits ranged from 0.1-0.6 microg Kg(-1), while Limits of Quantitation (LOQs) were 2, 1, 0.4, 1 and 2 microg Kg(-1) for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. For soil samples calculated LOQs were 2, 3, 1, 1, and 1 microg Kg(-1) for virginiamycin, monensin, salinomycin, narasin and nicarbazin, respectively. Application of the LC-MS-MS method for detection of veterinary pharmaceuticals in litter collected from commercial poultry farms showed that compounds were present at concentrations ranging from 10-11,000 microg Kg(-1).

Fast liquid chromatography/multiple-stage mass spectrometry of coccidiostats

Drugs that are used as medicines and also as growth promoters in veterinary care are considered as emerging environmental contaminants and in recent years concern about their potential risk to ecosystems and human health has risen. In this paper we used a method based on liquid chromatography/electrospray tandem mass spectrometry to analyze eight coccidiostatic compounds: diclazuril, dinitrocarbanilide (the main metabolite of nicarbazin), robenidine, lasalocid, monensin, salinomycin, maduramicin and nasarin. Multiple-stage mass spectrometry (MSn) based on the precursor ions [M+Na]+ (polyether ionophores), [M+H]+ (robenidine) and [M-H]- (diclazuril and dinitrocarbanilide) was used to study the fragmentation of these compounds. MSn data and genealogical relationships were used to propose a tentative assignment of the different fragment ions. Loss of water, decarboxylations, ketone beta-cleavages and rearrangement of cyclic ethers and amide groups were some of the fragmentations observed for these compounds. Liquid chromatography with a sub-2 microm particle size column was coupled to tandem mass spectrometry (LC/MS/MS) allowing the separation of these compounds in less than 7 min. Method detection limits ranging from 11 to 71 ng L(-1) and run-to-run values in terms of relative standard deviation (RSD) (up to 12%) were obtained.

Analysis of macrolide antibiotics, using liquid chromatography-mass spectrometry, in food, biological and environmental matrices

Macrolides are a group of antibiotics that have been widely used in human medical and veterinary practices. Analysis of macrolides and related compounds in food, biological, and environmental matrices continue to be the focus of scientists for the reasons of food safety, pharmacokinetic studies, and environmental concerns. This article presents an overview on the primary biological properties of macrolides and their associated analytical issues, including extraction, liquid chromatography-mass spectrometry (LC-MS), method validation, and measurement uncertainty. The main techniques that have been used to extract macrolides from various matrices are solid-phase extraction and liquid-liquid extraction. Conventional liquid chromatography (LC) with C18 columns plays a dominant role for the determination of macrolides, whereas ultra-performance liquid chromatography (UPLC) along with sub-2 microm particle C18 columns reduces run time and improves sensitivity. Mass spectrometry (MS), serving as a universal detection technique, has replaced ultraviolet (UV), fluorometric, and electrochemical detection for multi-macrolide analysis. The triple-quadrupole (QqQ), quadrupole ion trap (QIT), triple-quadrupole linear ion trap, time-of-flight (TOF), and quadrupole time-of-flight (QqTOF) mass spectrometers are current choices for the determination of macrolides, including quantification, confirmation, identification of their degradation products or metabolites, and structural elucidation. LC or UPLC coupled to a triple-quadrupole mass spectrometer operated in the multiple-reaction monitoring (MRM) mode (LC/MS/MS) is the first choice for quantification. UPLC-TOF or UPLC-QqTOF has been recognized as an emerging technique for accurate mass measurement and unequivocal identification of macrolides and their related compounds.

Simultaneous determination of pharmaceuticals, endocrine disrupting compounds and hormone in soils by gas chromatography-mass spectrometry

Analytical methods have been developed for simultaneous determination of six different pharmaceuticals and personal care products (PPCPs) (clofibric acid, ibuprofen, naproxen, ketoprofen, diclofenac, and triclosan), three endocrine disrupting compounds (EDCs) (4-tert-octylphenol, 4-n-nonylphenol, and bisphenol A (BPA)) and one estrogenic compound (estrone) in soil matrix. The soils were extracted by different solvents with the help of an ultrasonic treatment at 42 kHz, followed by a solid phase extraction (SPE) as a cleanup procedure. The purified extracts were derivatized with N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) and then analyzed by GC-MSD (SIM mode). The method was evaluated by testing the following variables: initial spiking levels, extraction solvents, solvent volumes, and soil types (sandy and clay soils). For 5 g of soil, four successive extraction steps with the mixture of acetone-ethyl acetate provided satisfactory recoveries. In the sandy soil, the recoveries of all the compounds were from 63.8 to 110.7% for the spiking level of 100 ng/g dry soil, and from 52.2 to 108.2% for 5 ng/g dry soil, respectively. Result was similar for the clay soil. The precision across all recoveries was high, suggesting that this method has a good reproducibility. The method was successfully employed to soil samples collected from a golf course irrigated with reclaimed wastewater in southern California, and resulted in the detection of clofibric acid, ibuprofen, naproxen, triclosan, bisphenol A, and estrone at ng per gram dry weight concentration levels. The method is robust and simple, and provides straightforward analyses of these current-emerging trace organic pollutants in solid matrices.

Fluoroquinolones in soil—risks and challenges

Fluoroquinolones (FQs) are among the most important antibacterial agents used in human and veterinary medicine. Because of the growing practice of adding manure and sewage sludge to agricultural fields these drugs end up in soils, where they can accumulate and have adverse effects on organisms. This paper presents an overview of recent developments in the determination of FQs in solid environmental matrices and describes the risks and challenges (persistence, fate, effects, and remediation) which result from their presence in soil.

Trace-level determination of pharmaceutical residues by LC-MS/MS in natural and treated waters. A pilot-survey study

A pilot-survey study was performed by collecting samples (influent and effluent wastewaters, rivers and tap waters) from different locations in Europe (Spain, Belgium, Germany and Slovenia). A solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry method was applied for the determination of pharmaceuticals (ibuprofen, naproxen, ketoprofen, diclofenac and clofibric acid). Method detection limits and method quantification limits were at the parts-per-trillion level (7.5-75 ng/L). The recovery rates of the SPE from deionized water and effluent wastewater samples spiked at 100- and 1,000-ng/L levels ranged from 87 to 95%. Identification criteria in compliance with the EU regulation for confirmatory methods of organic residues were applied. A detailed study of signal suppression evaluation for analysis of pharmaceutical residues in effluent wastewaters is presented.