Multiresidue analytical method for the simultaneous determination of 72 micropollutants in aqueous samples with ultra high performance liquid chromatography–high resolution mass spectrometry

Chemometric Optimization of SPE for the Determination of Multiclass Pesticides in Portable Water Samples by UHPLC-MS/MS

This study aimed on the development of a SPE-UHPLC-MS/MS method for the simultaneous determination of pesticide residues in drinking water samples. A chemometric approach was applied to optimize the efficiency of the SPE pretreatment procedure. This study involved (i) the application of a Full Factorial Design for the screening of the significant factors, (ii) the application of a Central Composite Design for the determination of the optimal conditions and (iii) the evaluation and validation of the significance of the statistically proposed models. Oasis HLB cartridges were used for the extraction. The optimum sample volume was 300 mL and the elution solvent 3 mL of the mixture of methanol:ethylacetate 70:30 v/v. The method was validated according to the international guidelines. Recoveries were ranged from 63 to 116% and the detection limits were between 0.1 and 1.5 pg mL- 1. The validated method could be used in routine analysis for pesticides screening.

Simultaneous evaluation of benzotriazoles, benzothiazoles and benzenesulfonamides in water samples from the impacted urban Jacarepaguá Lagoon System (Rio de Janeiro, Brazil) by liquid chromatography coupled to electrospray tandem mass spectrometry

Benzotriazoles, benzothiazoles, and benzenesulfonamides are emerging pollutants stable in aquatic media emitted by anthropogenic sources. Selected compounds of these classes were evaluated in the impacted urban Jacarepaguá Lagoon System (JLS) located in a tropical coastal region of Rio de Janeiro City, Brazil that has experienced a rapid expansion of urban occupation and environmental degradation in recent decades, and it represents a pioneering study of these compounds carried out in Brazilian areas. A method of solid phase extraction followed by ultra-performance liquid chromatography coupled to electrospray tandem mass-spectrometry was implemented to evaluate water samples collected in different water bodies (rivers, lagoons, and channels) of the JLS from March 2017 to May 2018. Limits of quantification (LOQs) ≤ 10.0 ng L^-1, method linearity up to 1000 μg L^-1, and recoveries between 62 and 121 % at three different levels were obtained. Individual concentrations varied from < LOQ to 5260 ng L^-1 (benzotriazole, in May 2018) which also predominated in all river samples. 2-mercaptobenzothiazole predominated in samples taken in lagoons and channels in March 2017, and 2-aminobenzothiazole was never detected. River samples showed total concentrations up to 30 times larger in all sampling campaigns, except March 2017 when the sample taken at Tijuca Lagoon showed the largest total concentration of the compounds studied due to the largest concentration of 2-mercaptobenzothiazole (2505 ng L^-1) found in this study. Principal component analysis (PCA) using only composition data was unable to distinguish samples from rivers, and lagoons and channels, but a PCA combining composition data and environmental parameters (pH, Eh, dissolved O₂ concentration, temperature, salinity, and conductivity) discriminated the samples according to two groups: rivers and lagoons and channels. The Joá Channel flows directly to the open sea and our data allowed a (preliminary) estimation of the total mass flows of the studied compounds to the open sea, which would vary between 1702 g day^-1 (March 2017) to 106 g day^-1 (May 2018) and allowed a preliminary estimative based on the geometric mean of input of 87.9 kg year^-1, indicating the importance of the drainage area to the contamination of the coastal area, and consequently to ocean pollution.

A new on-line SPE LC-HRMS method for simultaneous analysis of selected emerging contaminants in surface waters

In recent years emerging contaminants (ECs) have received significant attention due to their widespread detection in surface waters and concerns that these compounds can cause adverse ecological and/or human health effects. Therefore, accurate methods for determining and quantifying ECs in surface water are essential for estimating their environmental impact. This work describes the development, validation and application of a sensitive multiclass method for simultaneous determination of 22 per and polyfluorinated alkyl substances (PFASs), 3 pharmaceuticals, 15 pesticides, and 2 bisphenols in surface water using on-line solid phase extraction (SPE) coupled with ultra-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). The method allows simultaneous sample clean-up from interfering matrices and lower limits of detection (LODs) by injecting a large sample volume into the LC system without compromising chromatographic efficiency and resolution. Linearity of response over several orders of magnitude was demonstrated for all tested compounds (R2 > 0.99), with the LODs ranging from 0.8 and 33.7 pg mL-1, allowing detection of ECs at trace levels in surface water. The method showed acceptable accuracy and precision (CV, % and RE below 20%) for all tested ECs. It also provided recoveries between 60% and 130% for all tested ECs. The validated method was successfully applied for analysis of surface water samples from three rivers (Cam, Ouse and Thames) in England. Several ECs, including perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS), perfluorohexanoic acid (PFHxA), perfluorohexane sulfonic acid (PFHxS), dimethyl-metatoluamide (DEET) and ibuprofen were observed in analysed surface water above the method's limit of quantitation (LOQ), with concentrations ranging between 3.5 and 460 pg mL-1.

Development of a high-throughput multi-residue method for analysis of common pesticides in aquatic environments by automated online solid phase extraction coupled with LC-MS/MS

The present work describes the development of a fully automated method based on online solid phase extraction (SPE)-liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous analysis of multiple classes of pesticides or metabolites in drinking water (DW), surface water (SW), and wastewater effluents (WWEs). The target list covers 111 pesticides or metabolites of various properties and families. LC-MS/MS and online SPE parameters were optimized with regard to the sorbent type, mobile phase composition, wash volume, and flowrate as well as the injection volume. The method showed good linearity in two concentration ranges with 97% and 94% of the coefficients (R²) being higher than 0.99 in the low concentration range (0.1-100 ng L^-1) and high concentration range (100-2500 ng L^-1), respectively. High sensitivity was observed with method quantification limits (MQLs) of 0.03-5.3 ng L^-1, 0.06-17 ng L^-1, and 0.08-21 ng L^-1, for DW, SW, and WWE, respectively. The recoveries showed an accuracy of 94%, 91%, and 91% in the range of 70-130% for three matrices with satisfactory precision. The overall analysis time per sample was 30 min with minimum pretreatment. To the best of our knowledge, for the first time, 64 pesticides were identified by the high throughput online SPE-based method. The optimized method was used for WWE sample analysis, and 49 pesticides were detected in 12 WWE samples from an economically active city in China. Five pesticides were detected in all the samples, i.e. paclobutrazol, atrazine, diuron, acetamiprid, and triadimenol, and the highest median concentration was observed for carbendazim (324 ng L^-1). The advantages of the proposed method over offline ones make it have broad prospects in high throughput and reliable analysis of pesticides in aquatic environments.

A model-based analysis of the reactive transport behaviour of 37 trace organic compounds during field-scale bank filtration

Though bank filtration diminishes the loads of many trace organic compounds (TOrCs) present in the source water, still there is a wide uncertainty on the influence of local environmental conditions on biodegradation processes. This research addresses the fate and transport behaviour of 37 trace organic compounds at a bank filtration site in Germany over a relatively long-time span of six years. Using two-dimensional heat and reactive transport modelling in FEFLOW, TOrCs are classified according to their occurrence in bank filtration wells with a residence time of up to 4 months. We identify 12 persistent compounds, 20 reactive compounds and 5 transformation products formed during aquifer passage. Estimates of first-order biodegradation rate constants are given for six reactive compounds. Minimum biodegradation rate constants (i.e. maximum half-lives) are approximated for eight compounds only present in the surface water. For some compounds, a simple first-order degradation model did not yield satisfactory results and the behaviour appears to be more complex. Processes like sorption, redox- and/or temperature-dependent biodegradation and temperature-dependent desorption are suspected but incorporating these into the model was beyond the scope of this paper that provides an overview for many compounds. Results highlight the ability of the sub-surface to improve the water quality during bank filtration, yet at the same time show the persistence of several compounds in the aquifer.

Method development for simultaneous determination of polar and nonpolar pesticides in surface water by low-temperature partitioning extraction (LTPE) followed by HPLC-ESI-MS/MS

During this research, chemometric approaches were applied for optimization of the low-temperature partitioning extraction (LTPE) for the simultaneous analysis of the pesticides: acephate, difenoconazole, fenamidone, fluazifop, fluazinam, methamidophos, and thiamethoxam from surface water samples and determination by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. It was used the 2³ full factorial and the Doehlert experimental designs. The extraction technique was optimized by evaluating the effects of the three variables: sample pH, ionic strength (addition of Na₂HPO₄), and organic solvent volume. Considering the interest to find an optimal condition for all analytes simultaneously, the best extraction parameters found were as follows: pH = 5.33, concentration of Na₂HPO₄ = 0.0088 mol L^-1 and organic phase volume = 4.5 mL. The optimized methodology showed LOD and LOQ levels from 0.33 to 8.13 ng L^-1 and from 1.09 to 26.84 ng L^-1, respectively. The recovery values ranged from 38.37 and 99.83% and the RSD values varied from 2.33 to 18.92%. The method was applied to surface water analysis sampled in areas with intensive agricultural practices in Ouro Branco City, Minas Gerais, Brazil. The difenoconazole was detected in concentrations between 12.53 and 94.76 ng L^-1.

Qualitative and quantitative use of micropollutants as source and process indicators. A review

Nowadays, micropollutants such as pharmaceuticals, pesticides and personal care products can be found ubiquitously in the anthropogenically influenced water cycle. As micropollutants have virtually no natural background concentrations they are significantly more sensitive in detecting processes and flow paths than classic inorganic tracers and indicators and at the same time they are often highly source specific. Therefore, using micropollutants as environmental indicators for anthropogenic activities is a common and frequently applied method today. As they interact in many ways with environmental matrices they can be used for source apportionment as well as to estimate flow paths and residence times in waterbodies. This review gives a systematic overview over the large variety of micropollutants used as indicators in the aquatic environment over the last decades together with the prerequisites on their use. Their application is subdivided into their qualitative (compound presence or absence) and quantitative (volume flows) use and shows the numerous possibilities from gaining basic information on the water regime up to advanced applications such as wastewater-based epidemiology.

Recent advances of online coupling of sample preparation techniques with ultra high performance liquid chromatography and supercritical fluid chromatography

Ultra high performance liquid chromatography and supercritical fluid chromatography techniques are favored because of their high efficiency and fast analysis speed. Although many sample preparation techniques have been coupled with common liquid chromatography online, the online coupling of sample preparation with the two popular chromatography techniques have gained increasing attention owing to the increasing requirements of efficiency and sensitivity. In this review, we have discussed and summarized the recent advances of the online coupling of sample preparation with ultra high performance liquid chromatography and supercritical fluid chromatography techniques. The main sample preparation techniques that have been coupled with ultra high performance liquid chromatography online are solid-phase extraction and in-tube solid-phase microextraction, while solid-phase extraction and supercritical fluid extraction are the main techniques that have been coupled with supercritical fluid chromatography online. Especially, the strategies for online coupling of sample preparation with chromatography techniques were summarized. Typical applications and growing trends of the online coupling techniques were also discussed in detail. With the increasing demands of improving the efficiency, throughput, and analytical capability toward complex samples of the analysis methods, online coupling of sample preparation with chromatography techniques will acquire further development.

Micropollutants in drinking water from source to tap - Method development and application of a multiresidue screening method

A multi-residue screening method for simultaneous measurement of a wide range of micropollutants in drinking water (DW) resources was developed. The method was applied in a field study in central Sweden on water from source to tap, including samples of surface water (upstream and downstream of a wastewater treatment plant, WWTP), intake water before and after a DW treatment plant (DWTP, pilot and full-scale), treated DW leaving the plant and tap water at end users. Low detection limits (low ng L^-1 levels) were achieved by using large sample volumes (5 L) combined with ultra performance liquid chromatography high resolution mass spectrometry (UPLC-HRMS). In total, 134 different micropollutants were analyzed, including pesticides, pharmaceuticals and personal care products (PPCPs), drug-related compounds, food additives, and perfluoroalkyl substances (PFASs). Of these 134 micropollutants, 41 were detected in at least one sample, with individual concentrations ranging from sub ng L^-1 levels to ~80 ng L^-1. Two solid phase extraction (SPE) cartridges (Oasis HLB and Bond-Elut ENV) were shown to be complementary in the field study, with three compounds detected exclusively using HLB. The total concentration in treated drinking water (56-57 ng L^-1) was at a similar level as upstream from the WWTP (79-90 ng L^-1). The composition of micropollutants changed along the water path, to a higher fraction of food additives and PFASs. Median treatment efficiency in the full-scale DWTP was close to 0%, but with high variability for individual compounds. In contrast, median treatment efficiency in the pilot-scale DWTP was ~90% when using nanofiltration followed by a freshly installed granulated active carbon (GAC) filter.

Multiresidue analysis of 24 Water Framework Directive priority substances by on-line solid phase extraction-liquid chromatography tandem mass spectrometry in environmental waters

This paper reports the development of a fully multiresidue and automated on-line solid phase extraction (SPE) - liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of 24 priority substances (PS) belonging to different classes (pesticides, hormones or pharmaceuticals) included in the Directive 2013/39/UE and the recent Watch List (Decision 2015/495) in water samples (drinking water, surface water, and effluent wastewaters). LC-MS/MS conditions and on-line SPE parameters such as sorbent type, sample and wash volumes were optimized. The developed method is highly sensitive (limits of detection between 0.1 and 1.4ngL^-1) and precise (relative standard deviations lower than 8%). As part of the method validation studies, linearity, accuracy and matrix effects were assessed. The main advantage of this method over traditional off-line procedures is the minimization of tedious sample preparation increasing productivity and sample throughput. The optimized method was applied to the analysis of water samples and the results revealed the presence of 16 PS in river water and effluent water of wastewater treatment plants.

Assessment of quinoxyfen phototransformation pathways by liquid chromatography coupled to accurate mass spectrometry

Quinoxyfen has been recently identified as a priority hazardous substance in the field of the European water policy. In this work, its fate in aqueous samples and solid supports under UV and solar radiation is investigated. Diverse degradation experiments were carried out, at lab scale, using spiked aliquots of different aqueous matrices (ultrapure, treated wastewater and river water) irradiated at different wavelengths (λ = 254 nm, λ = 365 nm and solar light). Half-lives of quinoxyfen (2-26 min) depended on the wavelength and the intensity of radiation whilst the nature of the aqueous matrix did not play an important role in degradation kinetics. Moreover, experiments under solar radiation of doped silicone tubes were performed to simulate degradation when quinoxyfen is adsorbed on plant leaves or soil. As the compound is not completely mineralized, the identification of quinoxyfen transformation products (TPs) was performed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) injection of different irradiated time aliquots. The full-fragment ion spectra, at different collision energies, allowed the elucidation of the chemical structure of TPs formed by hydroxylation, cyclization or cleavage reactions. Five out of seven identified TPs have not been reported previously. The ecotoxicity simulation by software (TEST and ECOSAR) for TPs revealed that some of them could cause harmful effects to organisms such as Daphnia magna or Fathead minnow in a similar extent to the precursor; moreover, the time course profiles of major TPs (TP1 and TP2) revealed a much higher resistance to further photodegradation than quinoxyfen. Graphical abstract Quinoxyfen phototransformation pathways.

Development of potential candidate reference materials for drugs in bottom sediment, cod and herring tissues

Regular use of a reference material and participation in a proficiency testing program can improve the reliability of analytical data. This paper presents the preparation of candidate reference materials for the drugs metoprolol, propranolol, carbamazepine, naproxen, and acenocoumarol in freshwater bottom sediment and cod and herring tissues. These reference materials are not available commercially. Drugs (between 7 ng/g and 32 ng/g) were added to the samples, and the spiked samples were freeze-dried, pulverized, sieved, homogenized, bottled, and sterilized by γ-irradiation to prepare the candidate materials. Procedures for extraction and liquid chromatography coupled with tandem mass spectrometry were developed to determine the drugs of interest in the studied material. Each target drug was quantified using two analytical procedures, and the results obtained from these two procedures were in good agreement with each other. Stability and homogeneity assessments were performed, and the relative uncertainties due to instability (for an expiration date of 12 months) and inhomogeneity were 10-25% and 4.0-6.8%, respectively. These procedures will be useful in the future production of reference materials.

Development and validation of a multiresidue method for the analysis of more than 500 pesticides and drugs in water based on on-line and liquid chromatography coupled to high resolution mass spectrometry

Screening of a large number of emerging pollutants is highly desirable for the control of water quality. In this respect, a novel, fully automated contaminant screening method based on an integrated sample preconcentration and liquid chromatography coupled to high resolution mass spectrometry (SPE-UHPLC-HRMS) has been developed. The optimal chromatographic column and experimental conditions allowing the retention and subsequent elution of the maximum number of analytes were defined. Liquid chromatography and Q-exactive (Orbitrap™) parameters were optimized to obtain the best separation of molecules of interest, and the lowest detection limits. Due to the large amount of data to compare, a script written in R language was developed to evaluate the quality of the data generated by the comparison of 14 experimental conditions. The developed method enables the simultaneous semi quantitative analysis of 539 compounds (pesticides and drug residues), in 36 min with only 5 mL of water. Method validation was achieved through studies of repeatability, selectivity, linearity and matrix effect. Application to 20 tap water samples collected in and around Paris showed the presence of 34 different compounds all with concentrations below 0.1 μg/L, the European Union limit for drinking water. Pesticides and transformation products frequently found in water resources such as atrazine and its metabolites, hexazinone, oxadixyl, propazine and simazine were detected. Drug residues such as valsartan and carbamazepine, usually not monitored, were also found. The next step will be to assess the ability of this method to highlight the presence of unexpected contaminants not present in our database.

Depth profile of persistent and emerging organic pollutants upstream of the Three Gorges Dam gathered in 2012/2013

Persistent and emerging organic pollutants were sampled in September 2012 and 2013 at a sampling site in front of the Three Gorges Dam near Maoping (China) in a water depth between 11 and 61 m to generate a depth profile of analytes. A novel compact water sampling system with self-packed glass cartridges was employed for the on-site enrichment of approximately 300 L of water per sample to enable the detection of low analytes levels in the picogram per liter-scale in the large water body. The overall performance of the sampling system was acceptable for the qualitative detection of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), perfluoroalkylic acids (PFAAs), pharmaceutical residues and polar pesticides. Strongly particle-associated analytes like PAHs and PCBs resided mainly in the glass wool filter of the sampling system, whereas all other compounds have mainly been enriched on the XAD-resin of the self-packed glass cartridges. The sampling results revealed qualitative information on the presence, depth distribution and origin of the investigated compounds. Although the depth profile of PAHs, PCBs, OCPs, and PFAAs appeared to be homogeneous, pharmaceuticals and polar pesticides were detected in distinct different patterns with water depth. Source analysis with diagnostic ratios for PAHs revealed their origin to be pyrogenic (burning of coal, wood and grass). In contrast, most PCBs and OCPs had to be regarded as legacy pollutants which have been released into the environment in former times and still remain present due to their persistence. The abundance of emerging organic pollutants could be confirmed, and their most abundant compounds could be identified as perfluorooctanoic acid, diclofenac and atrazine among investigated PFAAs, pharmaceuticals and polar pesticides, respectively.

Simple and accurate measurement of carbamazepine in surface water by use of porous membrane-protected micro-solid-phase extraction coupled with isotope dilution mass spectrometry

To achieve fast and accurate analysis of carbamazepine in surface water, we developed a novel porous membrane-protected micro-solid-phase extraction (μ-SPE) method, followed by liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) analysis. The μ-SPE device (∼0.8 × 1 cm) was fabricated by heat-sealing edges of a polypropylene membrane sheet to devise a bag enclosing the sorbent. The analytes (both carbamazepine and isotope-labelled carbamazepine) were first extracted by μ-SPE device in the sample (10 mL) via agitation, then desorbed in an organic solvent (1 mL) via ultrasonication. Several parameters such as organic solvent for pre-conditioning of μ-SPE device, amount of sorbent, adsorption time, and desorption solvent and time were investigated to optimize the μ-SPE efficiency. The optimized method has limits of detection and quantitation estimated to be 0.5 ng L(-1) and 1.6 ng L(-1), respectively. Surface water samples spiked with different amounts of carbamazepine (close to 20, 500, and 1600 ng L(-1), respectively) were analysed for the validation of method precision and accuracy. Good precision was obtained as demonstrated by relative standard deviations of 0.7% for the samples with concentrations of 500 and 1600 ng kg(-1), and 5.8% for the sample with concentration of 20 ng kg(-1). Good accuracy was also demonstrated by the relative recoveries in the range of 96.7%-103.5% for all samples with uncertainties of 1.1%-5.4%. Owing to the same chemical properties of carbamazepine and isotope-labelled carbamazepine, the isotope ratio in the μ-SPE procedure was accurately controlled. The use of μ-SPE coupled with IDMS analysis significantly facilitated the fast and accurate measurement of carbamazepine in surface water.

High resolution mass spectrometry to investigate omeprazole and venlafaxine metabolites in wastewater

This study reports an investigation of omeprazole and venlafaxine parent substances and metabolites in Italian municipal influent wastewaters (IWWs). These pharmaceuticals were selected because they are widely consumed in Italy, but are poorly detected in waste and surface water. The aim of the study was to identify the most relevant pharmaceuticals metabolites in wastewater in order to improve the prioritization step and choose priority pollutants for environmental monitoring campaigns. This was done by investigating omeprazole, venlafaxine and their main metabolites in 30 IWWs from ten Italian cities and by comparing results with information from pharmacokinetic studies. Analysis was performed by solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) coupled to high resolution mass spectrometry (HRMS). We searched for 23 omeprazole and four venlafaxine metabolites using data-dependent and MS/MS methods. Parent omeprazole was never present in the samples. Six omeprazole metabolites were found in IWWs. Venlafaxine and two metabolites were present in all the samples. The metabolic profiles in Italian IWW agreed with results in IWW from Spain and with urinary excretion profiles from pharmacokinetic studies. Comparing results from different sources was useful to improve the identification of pharmaceuticals metabolites in environmental samples and to focus the attention of future studies on the most relevant compounds.

Development and validation of a generic nontarget method based on liquid chromatography - high resolution mass spectrometry analysis for the evaluation of different wastewater treatment options

A comprehensive workflow for using nontarget approaches as process evaluation tools was implemented, including data acquisition based on a LC-HRMS (QTOF) system using direct injection and data post-processing for the peak recognition in "full scan" data. Both parts of the approach were not only developed and validated in a conventional way using the suspected analysis of a set of spiked known micropollutants but also the nontarget analysis of a wastewater treatment plant (WWTP) effluent itself was utilized to consider a more environmental relevant range of analytes. Hereby, special focus was laid on the minimization of false positive results (FPs) during the peak recognition. The optimized data post-processing procedure reduced the percentage of FPs from 42% to 10-15%. Furthermore, the choice of a suitable chromatography for biological treated wastewater systems was also discussed during the method development. The workflow paid also attention to differences in the performance levels of the LC-HRMS system by implementation of an adaption system for intensity variations comparing different measurements dates or different instruments. The application of this workflow on wastewater samples from a municipal WWTP revealed that more than 91% compounds were eliminated by the biological treatment step and that the received effluent contained 55% newly formed potential transformation products.

Integrated targeted and non-targeted analysis of water sample extracts with micro-scale UHPLC-MS

A sensitive method is introduced to detect selected pharmaceutical residues and polar pesticides with UHPLC–MS in water samples of different origin. Active or passive water sampling was combined with a laboratory solid-phase extraction cleanup and stable isotope dilution analysis. Recovery experiments demonstrated that the internal standard correction performed well for the compensation of matrix effects. Besides, the original targeted analysis approach was expanded by non-target analysis of the samples with only one more consecutive injection run needed. The key benefits of this multi-residue analysis are:•

Targeted analysis and quantification combined with non-target analysis on a micro-scale UHPLC–MS system usually employed for qualitative analysis only.

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The internal standards for targeted analysis were used in non-target runs to calculate the partition coefficient log P of unknown substances employing the retention time index (RTI).

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The filtering of database hits for two criteria (exact mass and partition coefficient) significantly reduced the list of suspects and at the same time rendered it possible to perform non-target analysis with lower mass accuracy (no lock-spray) in the range of 20–500 ppm.

Rapid determination of 12 antibiotics and caffeine in sewage and bioreactor effluent by online column-switching liquid chromatography/tandem mass spectrometry

This study presents a column-switching solid-phase extraction online-coupled to a liquid chromatography/tandem mass spectrometry (SPE-LC-MS/MS) method for simultaneous analysis of 12 antibiotics (7 sulfonamides and 5 fluoroquinolones) and caffeine detected in the sewage and effluent of a pilot anaerobic reactor used in sewage treatment. After acidification and filtration, the samples were directly injected into a simple and conventional LC system. Backflush and foreflush modes were compared based on the theoretical plates and peak asymmetry observed. The method was tested in terms of detection (MDL) and quantification limit (MQL), linearity, relative recovery, and precision intra- and inter-day in lab-made sewage samples. The method presented suitable figures of merit in terms of detection, varying from 8.00 × 10(-5) to 6.00 × 10(-2) ng (0.800 up to 600 ng L(-1); caffeine) with direct injection volume of only 100 μL and 13 min of total analysis time (sample preparation and chromatographic run). When the method was applied in the analysis of sewage and effluent of the anaerobic reactor (n = 15), six antibiotics and caffeine were detected in concentrations ranging from 0.018 to 1097 μg L(-1). To guarantee a reliable quantification, standard addition was used to overcome the matrix effect.

Development of a Photoinduced Chemiluminescent Method for the Determination of the Herbicide Quinmerac in Water

A new, simple, and sensitive method, based on photoinduced chemiluminescence, was developed for the determination of quinmerac. The photoproduct, obtained after ultraviolet irradiation in basic medium, was mixed with sodium sulfite (sensitizer), and Ce(IV) (oxidant) in acid medium. A wide linear dynamic range (2-600 ng mL(-1)) and a limit of detection of 0.6 ng mL(-1) were obtained without any pretreatment (0.08 ng mL(-1) after solid-phase extraction). The determination was performed using a flow-injection manifold, which allowed a high throughput (144 h(-1)). The interday reproducibility was 5.6% (n = 5), and the intraday repeatability was 3.9 and 2.9% for 20 and 200 ng mL(-1) of quinmerac, respectively (n = 21). Finally, the method was applied to surface water and groundwater, with recoveries ranging from 78.1 to 94.5%.

New trends in sample preparation techniques for environmental analysis

Environmental samples include a wide variety of complex matrices, with low concentrations of analytes and presence of several interferences. Sample preparation is a critical step and the main source of uncertainties in the analysis of environmental samples, and it is usually laborious, high cost, time consuming, and polluting. In this context, there is increasing interest in developing faster, cost-effective, and environmentally friendly sample preparation techniques. Recently, new methods have been developed and optimized in order to miniaturize extraction steps, to reduce solvent consumption or become solventless, and to automate systems. This review attempts to present an overview of the fundamentals, procedure, and application of the most recently developed sample preparation techniques for the extraction, cleanup, and concentration of organic pollutants from environmental samples. These techniques include: solid phase microextraction, on-line solid phase extraction, microextraction by packed sorbent, dispersive liquid-liquid microextraction, and QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe).

Search for over 2000 current and legacy micropollutants on a wastewater infiltration site with a UPLC-high resolution MS target screening method

A target screening method using ultra high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) was developed. The method was applied to 14 groundwater and 11 surface water samples of a former wastewater infiltration site, where raw wastewater was applied until 1985 and treated wastewater is applied since 2005. The measured data are compared with mass spectrometric data of over 2000 organic micropollutants (OMPs), including pharmaceuticals, personal care products, pesticides, industrial chemicals and metabolites of these classes. A total number of 151 and 159 OMPs were detected in groundwater and surface water, respectively, of which 12 have not been reported before in these matrices. Among these 12 compounds were 11 pharmaceuticals and one personal care product. The identity of 55 of the detected OMPs (35%) was verified by analysis of standard compounds. Based on the distribution in the study area, two groups of OMPs were clearly distinguished: current OMPs introduced with treated municipal wastewater since 2005 and legacy OMPs originating from infiltration of untreated wastewater until 1985. A third group included OMPs contained in historic as well as in current wastewater. During infiltration, OMPs with molecular mass >500 g/mol and log DOW > 3.9 were preferentially removed. Speciation had a strong impact with cationic OMPs showing high, neutral OMPs medium and anionic OMPs lowest elimination during infiltration. This target screening method proved useful to study a wide range of compounds, even in retrospect and at sites with poorly documented history and with a complex and variable hydrological situation.

Quantitative performance of online SPE-LC coupled to Q-Exactive for the analysis of sofosbuvir in human plasma

A quantitative strategy towards the detection of sofosbuvir in human plasma was developed with online-SPE-LC-HRMS using t-MS², t-SIM and F-SIM modes.

On-line SPE-UHPLC method using fused core columns for extraction and separation of nine illegal dyes in chilli-containing spices

The presented work describes the development of a simple, fast and effective on-line SPE-UHPLC-UV/vis method using fused core particle columns for extraction, separation and quantitative analysis of the nine illegal dyes, most frequently found in chilli-containing spices. The red dyes Sudan I-IV, Sudan Red 7B, Sudan Red G, Sudan Orange G, Para Red, and Methyl Red were separated and analyzed in less than 9 min without labor-consuming pretreatment procedure. The chromatographic separation was performed on Ascentis Express RP-Amide column with gradient elution using mixture of acetonitrile and water, as a mobile phase at a flow rate of 1.0 mL min(-1) and 55°C of temperature. As SPE sorbent for cleanup and pre-concentration of illegal dyes short guard fused core column Ascentis Express F5 was used. The applicability of proposed method was proven for three different chilli-containing commercial samples. Recoveries for all compounds were between 90% and 108% and relative standard deviation ranged from 1% to 4% for within- and from 2% to 6% for between-day. Limits of detection showed lower values than required by European Union regulations and were in the range of 3.3-10.3 µg L(-1) for standard solutions, 5.6-235.6 µg kg(-1) for chilli-containing spices.

Temperature dependent redox zonation and attenuation of wastewater-derived organic micropollutants in the hyporheic zone

The hyporheic zone - a spatially fluctuating ecotone connecting surface water and groundwater - is considered to be highly reactive with regard to the attenuation of organic micropollutants. In the course of the presented study an undisturbed sediment core was taken from the infiltration zone of a bank filtration site in Berlin and operated under controlled laboratory conditions with wastewater-influenced surface water at two different temperatures, simulating winter and summer conditions. The aim was to evaluate the fate of site-relevant micropollutants, namely metoprolol, iopromide, diclofenac, carbamazepine, acesulfame, tolyltriazole, benzotriazole, phenazone and two phenazone type metabolites, within the first meter of infiltration dependent on the prevailing temperature. A change in temperature resulted in a development of significantly distinct redox conditions. Both temperature dependencies and related redox dependencies were identified for all micropollutants except for benzotriazole and carbamazepine, which behaved persistent under all conditions. For the remaining compounds degradation rate constants generally decreased from warm and oxic/penoxic/suboxic over cold and oxic/penoxic to warm and manganese reducing (transition zone). Individual degradation rate constants ranged from 0 (e.g. diclofenac, acesulfame and tolyltriazole in the transition zone) to 1.4×10(-4)s(-1) for metoprolol under warm conditions within the oxic to suboxic zone.

How a complete pesticide screening changes the assessment of surface water quality

A comprehensive assessment of pesticides in surface waters is challenging due to the large number of potential contaminants. Most scientific studies and routine monitoring programs include only 15-40 pesticides, which leads to error-prone interpretations. In the present study, an extensive analytical screening was carried out using liquid chromatography-high-resolution mass spectrometry, covering 86% of all polar organic pesticides sold in Switzerland and applied to agricultural or urban land (in total 249 compounds), plus 134 transformation products; each of which could be quantified in the low ng/L range. Five medium-sized rivers, containing large areas of diverse crops and urban settlements within the respective catchments, were sampled between March and July 2012. More than 100 parent compounds and 40 transformation products were detected in total, between 30 and 50 parent compounds in each two-week composite sample in concentrations up to 1500 ng/L. The sum of pesticide concentrations was above 1000 ng/L in 78% of samples. The chronic environmental quality standard was exceeded for 19 single substances; using a mixture toxicity approach, exceedances occurred over the whole measurement period in all rivers. With scenario calculations including only 30-40 frequently measured pesticides, the number of detected substances and the mixture toxicity would be underestimated on average by a factor of 2. Thus, selecting a subset of substances to assess the surface water quality may be sufficient, but a comprehensive screening yields substantially more confidence.

Suspect screening and target quantification of multi-class pharmaceuticals in surface water based on large-volume injection liquid chromatography and time-of-flight mass spectrometry

The ever-growing number of emerging micropollutants such as pharmaceuticals requests rapid and sensitive full-spectrum analytical techniques. Time-of-flight high-resolution mass spectrometry (TOF-HRMS) is a promising alternative for the state-of-the-art tandem mass spectrometry instruments because of its ability to simultaneously screen for a virtually unlimited number of suspect analytes and to perform target quantification. The challenge for such suspect screening is to develop a strategy, which minimizes the false-negative rate without restraining numerous false-positives. At the same time, omitting laborious sample enrichment through large-volume injection ultra-performance liquid chromatography (LVI-UPLC) avoids selective preconcentration. A suspect screening strategy was developed using LVI-UPLC-TOF-MS aiming the detection of 69 multi-class pharmaceuticals in surface water without the a priori availability of analytical standards. As a novel approach, the screening takes into account the signal-intensity-dependent accurate mass error of TOF-MS, hereby restraining 95 % of the measured suspect pharmaceuticals present in surface water. Application on five Belgian river water samples showed the potential of the suspect screening approach, as exemplified by a false-positive rate not higher than 15 % and given that 30 out of 37 restrained suspect compounds were confirmed by the retention time of analytical standards. Subsequently, this paper discusses the validation and applicability of the LVI-UPLC full-spectrum HRMS method for target quantification of the 69 pharmaceuticals in surface water. Analysis of five Belgian river water samples revealed the occurrence of 17 pharmaceuticals in a concentration range of 17 ng L(-1) up to 3.1 μg L(-1).

Sorption behavior of 20 wastewater originated micropollutants in groundwater--column experiments with pharmaceutical residues and industrial agents

Since sorption is an essential process with regard to attenuation of organic pollutants during subsurface flow, information on the sorption properties of each pollutant are essential for assessing their environmental fate and transport behavior. In the present study, the sorption behavior of 20 wastewater originated organic micropollutants was assessed by means of sediment column experiments, since experimentally determined data for these compounds are not or sparsely represented in the literature. Compounds investigated include various psychoactive drugs, phenazone-type pharmaceuticals and β-blockers, as well as phenacetine, N-methylphenacetine, tolyltriazole and para-toluenesulfonamide. While for most of the compounds no or only a low sorption affinity was observed, an elevated tendency to sorb onto aquifer sand was obtained for the β-blockers atenolol, propranolol and metoprolol. A comparison between experimental data and data estimated based on the octanol/water partition coefficient following the QSAR approach demonstrated the limitations of the latter to predict the adsorption behavior in natural systems for the studied compounds.

Determination of pesticide residues and related compounds in water and industrial effluent by solid-phase extraction and gas chromatography coupled to triple quadrupole mass spectrometry

Pollution of drinking water supplies from industrial waste is a result of several industrial processes and disposal practices, and the establishment of analytical methods for monitoring organic compounds related to environmental and health problems is very important. In this work, a method using solid-phase extraction (SPE) and gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) was developed and validated for the simultaneous determination of pesticide residues and related compounds in drinking and surface water as well as in industrial effluent. Optimization of the method was achieved by using a central composite design approach on parameters such as the sample pH and SPE eluent composition. A single SPE consisting of the loading on a polymeric sorbent of 100 mL of sample adjusted to pH 3 and elution with methanol/methylene chloride (10:90, v/v) permitted the obtaining of acceptable recoveries in most cases. The concentration factor associated with sensitivity of the chromatographic analysis permitted the achievement of the method limit of detection values between 0.01 and 0.25 μg L(-1). Recovery assays presented mean recoveries between 70 and 120% for most of the compounds with very good precision, despite the different chemical nature of the compounds analyzed. The selectivity of the method, evaluated through the relative intensity of quantification and qualification ions obtained by GC-QqQ-MS/MS, was considered adequate. The developed method was finally applied to the determination of target analytes in real samples. River water and treated industrial effluent samples presented residues of some compounds, but no detectable residues were found in the drinking water samples evaluated.

HPLC column-switching technique for sample preparation and fluorescence determination of propranolol in urine using fused-core columns in both dimensions

A new and fast high-performance liquid chromatography (HPLC) column-switching method using fused-core columns in both dimensions for sample preconcentration and determination of propranolol in human urine has been developed. On-line sample pretreatment and propranolol preconcentration were performed on an Ascentis Express RP-C-18 guard column (5 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water (5:95, v/v) at a flow rate of 2.0 mL min(-1) and at a temperature of 50 °C. Valve switch from pretreatment column to analytical column was set at 4.0 min in a back-flush mode. Separation of propranolol from other endogenous urine compounds was achieved on the fused-core column Ascentis Express RP-Amide (100 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water solution of 0.5% triethylamine, pH adjusted to 4.5 by means of glacial acetic acid (25:75, v/v), at a flow rate of 1.0 mL min(-1) and at a temperature of 50 °C. Fluorescence excitation/emission detection wavelengths were set at 229/338 nm. A volume of 1,500 μL of filtered urine sample solution was injected directly into the column-switching HPLC system. The total analysis time including on-line sample pretreatment was less than 8 min. The experimentally determined limit of detection of the method was found to be 0.015 ng mL(-1).