Environmental Mass Spectrometry: Emerging Contaminants and Current Issues

Treating disinfection byproducts with UV or solar irradiation and in UV advanced oxidation processes: A review

This review focuses on the degradation kinetics and mechanisms of disinfection byproducts (DBPs) under UV and solar irradiation and in UV-based advanced oxidation processes (AOPs). A total of 59 such compounds are discussed. The processes evaluated are low pressure, medium pressure and vacuum UV irradiation, solar irradiation together with UV/hydrogen peroxide, UV/persulfate and UV/chlorine AOPs. Under UV and solar irradiation, the photodegradation rates of N-nitrosamines are much higher than those of halogenated DBPs. Among halogenated DBPs, those containing iodine are photodegraded more rapidly than those containing bromine or chlorine. This is due to differences in their bond energies (E_N-N < E_C-I < E_C-Br < E_C-Cl). Molar absorption coefficients at 254 nm and energy gaps can be used to predict the photodegradation rates of DBPs under low pressure UV irradiation. But many DBPs of interest cannot be degraded to half their original concentration with less than a 500 mJ cm^-2 dose of low pressure UV light. HO^• generally contributes to less than 30% of the degradation of DBPs except iodo-DBPs in UV/H₂O₂ AOPs. Reaction mechanisms under UV irradiation and in HO^•-mediated oxidation are also summarized. N-N bond cleavage initiates their direct UV photolysis of N-nitrosamines as C-X cleavage does among halogenated compounds. HO^• generally initiates degradation via single electron transfer, addition and hydrogen abstraction pathways. Information on the reaction rate constants of SO₄^•- and halogen radicals with DBPs is rather limited, and little information is available about their reaction pathways. Overall, this review provides improved understanding of UV, solar and AOPs.

Halogen-sensitive solvatochromism based on a phenolic polymer of tetraphenylethene

Herein, we describe the successful preparation of a methylene-bonded tetraphenylethene polymer using a phenolic-resin synthesis protocol. Our novel phenolic polymer showed solvatochromism in response to halogenated organic solvents. Solvatochromism is induced by halogen/π interactions between the polymer and the organic halide.

Herein, we describe novel phenolic polymer showed solvatochromism in response to halogenated organic solvents through halogen/π interactions.

Detection of contaminants in water supply: A review on state-of-the-art monitoring technologies and their applications

Water monitoring technologies are widely used for contaminants detection in wide variety of water ecology applications such as water treatment plant and water distribution system. A tremendous amount of research has been conducted over the past decades to develop robust and efficient techniques of contaminants detection with minimum operating cost and energy. Recent developments in spectroscopic techniques and biosensor approach have improved the detection sensitivities, quantitatively and qualitatively. The availability of in-situ measurements and multiple detection analyses has expanded the water monitoring applications in various advanced techniques including successful establishment in hand-held sensing devices which improves portability in real-time basis for the detection of contaminant, such as microorganisms, pesticides, heavy metal ions, inorganic and organic components. This paper intends to review the developments in water quality monitoring technologies for the detection of biological and chemical contaminants in accordance with instrumental limitations. Particularly, this review focuses on the most recently developed techniques for water contaminant detection applications. Several recommendations and prospective views on the developments in water quality assessments will also be included.

Highly efficient inactivation of bacteria found in drinking water using chitosan-bentonite composites: Modelling and breakthrough curve analysis

Disinfection of bacterially-contaminated drinking water requires a robust and effective technique and can be achieved by using an appropriate disinfectant material. The advanced use of nanomaterials is observed as an alternative and effective way for the disinfection process and water treatment as a whole. Hence, the inactivation of Escherichia coli (E. coli) using chitosan-Bentonite (Cts-Bent) composites was studied in a fixed bed column. Cts-Bent composites were synthesized using in situ cross-linking method using Bent-supported silver and zinc oxide nanoparticles. These composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The effect of the composite bed mass, initial concentration of bacteria, and flow rate on the bacterial inactivation was investigated. The characterization results revealed that the composites were successfully prepared and confirmed the presence of both silver and zinc oxide nanoparticles in the chitosan matrix. The growth curves of E. coli were expressed as breakthrough curves, based on the logistic, Gompertz, and Boltzmann models. The breakthrough time and processed volume of treated water at breakthrough were used as performance indicators, which revealed that the composites performed best at low bacterial concentration and flow rate and with substantial bed mass. The chitosan composites were found to be highly effective, which was demonstrated when no bacteria were observed in the effluent sample within the first 27 h of analysing river water. All the models were suitable for adequately describing and reproducing the experimental data with a sigmoidal pattern. Therefore, the prepared composite is showing potential to work as a disinfectant and provide an alternative solution for water disinfection; hence this study should propel further research of the same or similar materials.

Occurrence, fate and risk assessment of personal care products in river-groundwater interface

This work presents the occurrence and fate of selected personal care products (PCPs) in the urban river-groundwater interface. To this end, urban river and groundwater samples were collected in Sant Adrià del Besòs (NE of Spain) and a total of 16 PCPs were analyzed including benzophenone derivatives, camphor derivatives, p-aminobenzoic acid derivatives, triazoles and parabens in three different campaigns (from May 2010 to July 2014). These compounds reach the aquifer through the recharge of Besòs River that receives large amounts of effluents from waste water treatment plants. Results have shown that most of the compounds were not or barely detected (maximum concentrations around 200ng/L) in groundwater samples during the different sampling campaigns. Only two triazoles, namely benzotriazole (BZT) and methyl benzotriazol (MeBZT) were found at high concentrations in groundwater samples (maximum concentration around 2000ng/L). The fate of PCPs in the aquifer was assessed using mixing analysis considering the seasonal variability of the Besòs River. Overall, measured groundwater concentrations were significantly much lower than those estimated by the mixing of the river water. This observation suggested that most of the PCPs are naturally removed when river water infiltrates the aquifer. However, some compounds were more persistent in the aquifer. These compounds were in descending order: the triazoles BZT and MeBZT followed by the camphor derivative 4MBC and the paraben MePB. The measured concentrations allowed us to assess the environmental risk posed by the selected UV-filters and parabens in the river and groundwater samples. Hazard Quotients (HQs) for different aquatic species were calculated in order to characterize the ecotoxicity potential of the studied compounds in the river-groundwater interface. HQ values were always below 1 indicating that at the concentrations observed in the surface or aquifer water of Besòs River these compounds pose no risk to the selected aquatic organisms.

Photophysical and photochemical properties of the pharmaceutical compound salbutamol in aqueous solutions

Salbutamol is a potent β(2)-adrenergic receptor agonist widely used in the treatment of bronchial asthma and chronic obstructive pulmonary disease. An increasing number of studies have detected salbutamol in natural water systems worldwide. Studies have shown that sunlight degrades salbutamol resulting in the formation of products; some showing higher toxicity to bacteria Vibrio fischeri than the parent compound. In this contribution, steady-state absorption and emission techniques, high-performance liquid chromatography, and transient absorption spectroscopy are used to investigate the photochemistry of salbutamol in aqueous buffer solutions at controlled pH values. Ground- and excited-state calculations that include solvent effects are performed to guide the interpretation of the experimental results. Salbutamol is sensitive to UVB light absorption in the pH range from 3 to 12, forming products that absorb light at longer wavelengths than the parent compound. Quantum yields of degradation reveal that the deprotonated species is 10-fold more photo-active than the protonated species. In line with this result, the fluorescence quantum yield of the protonated species is more than an order of magnitude higher than that of the deprotonated species. Transient absorption spectroscopy shows that population of the triplet state occurs with a rate constant of 7.1×10(8)s(-1) in the protonated species, while a rate constant of 1.7×10(10)s(-1) is measured for the deprotonated species. While degradation of the deprotonated species is not affected by the presence of molecular oxygen, a twofold increase in the photodegradation yield of the protonated species in air-saturated conditions is observed.

Determination of nitrosamines in water by gas chromatography/chemical ionization/selective ion trapping mass spectrometry

A gas chromatography/mass spectrometry (GC/MS) method for determination of nine N-nitrosamines (NAs) in water is described. Two ionization modes, electron impact (EI) and chemical ionization (CI) with methanol, as well as different ion analysis techniques, i.e. full scan, selected ion storage (SIS) and tandem mass spectrometry (MS/MS) were tested. Chemical ionization followed by SIS resulted the mass spectrometric method of choice, with detection limits in the range of 1-2ng/L. Solid Phase Extraction (SPE) with coconut charcoal cartridges was applied to extract NAs from real samples, according EPA Method 521. Drinking water samples were collected from seven surface- and two groundwater treatment plants. Three surface water treatment plants were sampled before and after addition of O(3)/ClO(2) to observe the effect of disinfection on NAs' formation. N-nitrosodiethylamine (NDEA), n-nitrosodipropylamine (NDPA), n-nitrosomorpholine (NMOR) and n-nitrosodibutylamine (NDBA) were found up to concentrations exceeding three times the risk level of 10ng/L set by the California Department of Public Health. Because dermal adsorption has been recently indicated as a new contamination route of exposure to NAs for people who practice swimming activity, water samples from five swimming pools in the Bologna (Italy) area were collected. N-nitrosopyrrolidine (NPYR) was detected in all samples at concentrations larger than 50ng/L, likely as a disinfection by-product from the amino acid precursor proline, a main constituent of skin collagen.

Limitations of electrospray ionization in the analysis of a heterogeneous mixture of naturally occurring hydrophilic and hydrophobic compounds

A model heterogeneous mixture of a hydrophilic tripeptide (phenylalanine-glycine-glycine, PGG) and hydrophobic organic acids ((12)C- and (13)C-octanoic acid and pentadecanoic acid) was subjected to electrospray ionization mass spectrometry (ESI-MS). The objective was to verify the previously noted inconsistencies in ESI-MS of complex environmental samples such as humic materials from either aquatic or terrestrial origins. The hydrophobic organic acids, either alone or together, reduced significantly the ESI-MS detection of the tripeptide molecular and self-associated ions at a concentration that was an order of magnitude lower than that of PGG. The most intense peaks were invariably those of the octanoic acid as either deprotonated, self-associated, or acetate-clustered molecules. The presence of equimolar amounts of PGG and organic acids yielded similar results, but with a significant increased detection of PDA and a smaller depression of the PGG signals. This behaviour is attributed to a different electrospray ionization of the mixture compounds depending on their most probable positioning at the surface of the evaporating droplet. The most favoured positioning of hydrophobic molecules at the aqueous-gas interphase allows preferential evaporation of hydrophobic ions whereas the hydrophilic molecules are retained in the droplet interior, and, their ESI-MS detection depressed. These findings suggest that the electrospray ionization of different molecules present in complex heterogeneous mixtures of environmental significance such as humic substances is limited by their concentration and reciprocal attracting forces.

Assessment of matrix-dependent analyte stability and volatility during open-vessel sample dissolution for arsenic, cadmium, mercury and selenium

The effects of calcium and magnesium (as nitrates) and phosphorous (as hydrogen phosphate) were investigated on the stability of As, Cd, Hg, and Se during open-vessel dissolution in Teflon vessels. Samples of mainly inorganic and biological matrices were dissolved in screw-capped Teflon tubes in HNO(3) only or in a mixture of HNO(3)-HF. The caps were then removed and the solutions were simultaneously evaporated at 120 °C to near dryness without drying the contents (Method I) or to complete dryness with extended heating for 20 min at dryness (Method II). ICP-MS analysis indicated that the stabilities of Se and Hg were highly influenced by Ca, Mg and PO(4) content in the sample. Arsenic (As) and Cd did not show any significant instability or volatility. Selenium was lost in Method II from biological samples containing trace levels of Ca, Mg and PO(4). Mercury was unstable during heating in all samples, except bone ash for which no significant loss was detected in Method I. Losses observed for Hg and Se were consistent with Ca, Mg and PO(4) deficiency in the samples and hence indicated that nitrate and hydrogen phosphate salts of these matrix elements do improve stability of the relatively volatile elements during open-vessel dissolution in teflon vessels. While Se was effectively stabilized with sub-per cent levels of Ca, Mg and PO(4), Hg due its high volatility required significantly higher levels of Ca and PO(4) in the bone ash.

Toxicity identification fractionation of environmental estrogens in waste water and sludge using gas and liquid chromatography coupled to mass spectrometry and recombinant yeast assay

We developed a toxicity identification fractionation (TIF) procedure to determine estrogenic compounds in wastewaters and sludge. The procedure consisted in fractionation of samples through a C(18) solid-phase extraction cartridge, in which Fraction I contained nonylphenol (NP) and its mono (NPEO(1)) and diethoxylate (NPEO(2)) and the markers of faecal exposure, Fraction II contained bisphenol A (BPA) and synthetic and natural hormones, and Fraction III contained the hormone conjugates. These three fractions were analyzed in parallel using gas or liquid chromatography coupled to mass spectrometry and recombinant yeast assay (RYA). Water samples collected daily throughout a whole week contained from 0.45 to 7.22 microg L(-1) of NP > NPEO(1) > NPEO(2) and were responsible for the estrogenicity of these samples. Fractions II and III were not estrogenic and that was due to the low ng L(-1) level of hormones and hormone conjugates found, respectively. The biological treatment sewage treatment plant (STP) was capable to eliminate from 52 to 100% of the compounds, with bisphenol A being the least removed. Only alkylphenols were accumulated in sludge with concentrations from 8.69 to 26.3 mg kg(-1) dw of NPEO(1) > NPEO(2) > NP. The integrated procedure herein proposed can be used as a screening method to evaluate estrogenic compounds in STPs and to survey faecal elimination.

Seasonal variability of the reduction in estrogenic activity at a municipal WWTP

In vitro monitored estrogenicity of municipal wastewater influent/effluent samples (collected from September to December from a Northern Canadian biological nutrient removal (BNR) treatment plant serving an urban population of 750,000) were combined with operational, wastewater quality, and climate data to determine which of these latter variables may be related to the levels and reduction in the former parameter. Significant variability was present in operational and wastewater quality parameters throughout the sampling period including a 7 degrees C difference in wastewater temperature Most of the wastewater samples collected during this period show a considerable amount of recombinant yeast assay (RYA) activity with the greatest activity (estradiol (E2)-equivalents of 106-175ng/L) seen in the final effluents collected from mid-September to mid-October. Percent reduction in the levels of RYA measured E2-equivalents varied from -234% to 75%. No correlations were seen in RYA activity reduction with percent reduction in 5-day biochemical oxygen demand (BOD(5)), flow (i.e. inversely related to hydraulic retention time), solids retention time or even rainfall, and the reduction trends for RYA measured activity were explained best by ambient and effluent temperatures in an inverse fashion (% reduction in E2-equivalents=-10.8.(effluent temperature in degrees C)+191, p=0.005). Complementary instrumental analysis of select sample composites revealed that the free/conjugated estrogen ratio was indeed greater in the wastewater sampled during warmer temperatures.

Development of a tolerable daily intake for N-nitrosodimethylamine using a modified benchmark dose methodology

N-Nitrosodimethylamine (NDMA) is an environmental contaminant that has recently been detected in Australian drinking-water supplies and that is principally generated in chloramination systems. NDMA is acutely toxic to humans at high doses, is genotoxic after cytochrome P-450 metabolism, and is carcinogenic in several animal species. An extremely large lifetime cancer dose-response study reported by Peto and colleagues (1984, 1991a, 1991b) of NDMA in drinking water given to rats is used in risk assessment by various jurisdictions. We have recently reported on use of an Australian modified benchmark dose (mBMD) methodology for developing tolerable daily intakes (TDIs) and guideline values for environmental carcinogens based on cancer dose response in the low-dose region, and have applied this to the NDMA rat liver tumor data. The application of a suite of mathematical models to the incidence data for hepatocellular carcinomas and hemangiosarcomas, followed by arithmetic and exponential-weight averaging of the 5% extra risk dose (mBMD(0.05)) for the various models, produced an mBMD(0.05) range of 0.020-0.028 mg/kg/d. This was then divided by a range of modifying factors to account for seriousness of the carcinogenic endpoint, adequacy of the database, and inter- and intraspecies differences, generating a TDI range of 4.0 to 9.3 ng/kg/d. This may be employed in developing guideline values for NDMA in environmental media.

Biodegradation of diphenyl ether and transformation of selected brominated congeners by Sphingomonas sp. PH-07

Polybrominated diphenyl ethers (PBDEs) are common flame-retardant chemicals that are used in diverse commercial products such as textiles, circuit boards, and plastics. Because of the widespread production and improper disposal of materials that contain PBDEs, there has been an increasing accumulation of these compounds in the environment. The toxicity and bioavailability of PBDEs are variable for different congeners, with some congeners showing dioxin-like activities and estrogenicity. The diphenyl ether-utilizing bacterium Sphingomonas sp. PH-07 was enriched from activated sludge of a wastewater treatment plant. In liquid cultures, this strain mineralized 1 g of diphenyl ether per liter completely within 6 days. The metabolites detected and identified by gas chromatography/mass spectrometry (MS) and electrospray ionization/MS analysis corresponded with a feasible degradative pathway. However, the strain PH-07 even catabolized several brominated congeners such as mono-, di-, and tribrominated diphenyl ethers thereby producing the corresponding metabolites.

Potential sources of background contaminants in solid phase extraction and microextraction

A study to identify the sources of background contamination from SPE, using a C-18 sorbent, and solid-phase microextraction (SPME), using a 70 microm carbowax/divinylbenzene (CW/DVB) fiber, was carried out. To determine the source of contamination, each material used in the procedure was isolated and examined for their contribution. The solid-phase column components examined were: sorbent material and frits, column housings and each solvent used to elute analytes off the column. The components examined in the SPME procedure were: SPME fiber, SPME vials, water (HPLC grade), and salt (sodium chloride) used to increase the ionic strength. The majority of the background contaminants from SPE were found to be from the SPE sorbent material and frits. The class of contaminants extracted during a blank extraction were phthalates and other plasticizers used during the manufacturing process. All had blank levels corresponding to measured concentrations below 2 ng/ mL, except for undecane, which had a concentration of 5.4 ng/mL. The most prevalent contaminants in the SPME blank procedure are 1,9-nonanediol, a mixture of phthalates and highly bis-substituted phenols. All the concentrations were below 2 ng/mL, with the exception of bis (2-ethylhexyl) phthalate, which had concentrations ranging from 5 to 20 ng/mL.

Microwave-accelerated derivatization for the simultaneous gas chromatographic-mass spectrometric analysis of natural and synthetic estrogenic steroids

A rapid microwave-accelerated derivatization process for the GC-MS analysis of steroid estrogens, estrone (E1), 17beta-estradiol (E2), estriol (E3), 17alpha-ethynylestradiol (EE2) and mestranol (MeEE2), was developed. Under microwave irradiation, the five estrogenic hormones studied were simultaneously derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+trimethylchlorosilane (TMCS) in pyridine solution. Effects of irradiation time (15-120 s) and power level (240-800 W) on the yield of the derivatization were investigated. The derivatization under the irradiation of 800 W microwave for 60s produced comparable results when compared with the conventional heating process in a sand bath for 30 min at 80 degrees C in terms of derivatization yield, linearity and precision for all steroid hormones tested. The calibration curves are linear between 3.00 and 3.00 x 10(2) microg mL(-1). The square of the regression coefficients (R(2)) range from 0.979 to 1.000. The applicability of the method was evaluated on spiked river and distilled water samples at two concentrations, 25.0 and 2.00 x 10(2) ng mL(-1). The recoveries obtained by using microwave heating (60s, 800 W) were similar to those by conventional heating. When combined solid-phase extraction (SPE) with the application of the microwave-accelerated derivatization proposed here, the detection limits of 0.02-0.1 ng L(-1) for the steroid hormones have been achieved. The results demonstrated that microwave-accelerated derivatization is an efficient and suitable sample preparation method for the GC-MS analysis of estrogenic steroids.

Determination of priority organic micro-pollutants in water by gas chromatography coupled to triple quadrupole mass spectrometry

A multiclass method has been developed for screening, quantification and confirmation of organic micro-pollutants in water by gas chromatography coupled to mass spectrometry with a triple quadrupole analyzer. The work has been focused on the determination of more than 50 compounds belonging to different chemical families: 19 organochlorine and organophosphorus insecticides, 6 herbicides, 7 polychlorinated biphenyls, 16 polycyclic aromatics hydrocarbons, 2 brominated diphenyl ethers, and 3 octyl/nonyl phenols and pentachlorobenzene. Most of these analytes are included in the list of priority substances in the framework on European Water Policy. Analyte extraction was performed by solid phase extraction using C18 cartridges, and five isotopically labeled standards were added before extraction as surrogates. Analyses were performed by gas chromatography with tandem mass spectrometry (MS/MS) in electron impact mode. Accuracy and precision were evaluated by means of recovery experiments using water samples fortified at two concentration levels (25 and 250 ng L(-1)), with satisfactory results for most of analytes. The excellent selectivity and sensitivity reached in selected reaction monitoring mode allowed us satisfactory quantification and confirmation at levels as low as 25 ng L(-1). Two MS/MS transitions were acquired for each analyte, using the Q/q intensity ratio as a confirmatory parameter. The method developed was applied to the analysis of surface, ground and wastewater samples collected from the Valencia Region (Spain). Analytical methodology using negative chemical ionization mode was also validated for the organochlorine compounds selected, showing a superior sensitivity and lower detection limits.

Recently developed GC/MS and LC/MS methods for determining NSAIDs in water samples

Pharmaceuticals have become major targets in environmental chemistry due to their presence in aquatic environments (following incomplete removal in wastewater treatment or point-source contaminations), threat to drinking water sources and concern about their possible effects to wildlife and humans. Recently several methods have been developed for the determination of drugs and their metabolites in the lower nanogram per litre range, most of them using solid-phase extraction (SPE) or solid-phase microextraction (SPME), derivatisation and finally gas chromatography mass spectrometry (GC-MS), gas chromatography tandem mass spectrometry (GC-MS/MS) and liquid chromatography electrospray tandem mass spectrometry (LC-ES/MS/MS). Due to the elevated polarity of non-steroidal anti-inflamatory drugs (NSAIDs), analytical techniques based on either liquid chromatography coupled to mass spectrometry (LC-MS) and gas chromatography coupled to mass spectrometry (GC-MS) after a previous derivatisation step are essential. The most advanced aspects of current GC-MS, GC-MS/MS and LC-MS/MS methodologies for NSAID analysis are presented.

Characterization of new nitrosamines in drinking water using liquid chromatography tandem mass spectrometry

N-Nitrosodimethylamine (NDMA), a member of a group of probable human carcinogens, has been detected as a disinfection byproduct (DBP) in drinking water supplies in Canada and the United States. To comprehensively investigate the occurrence of possible nitrosamines in drinking water supplies, a liquid chromatography-tandem mass spectrometry technique was developed to detect both thermally stable and unstable nitrosamines. This technique consisted of solid-phase extraction (SPE), liquid chromatography (LC) separation, and tandem quadrupole linear ion trap mass spectrometry (MS/MS) detection. It enabled the determination of sub-ng/L levels of nine nitrosamines. Isotope-labeled N-nitrosodimethylamine-d6 (NDMA-d6) was used as the surrogate standard for determining recovery, and N-nitrosodi-n-propylamine-dl4 (NDPA-dl4) was used as the internal standard for quantification. The method detection limits were estimated to be 0.1-10.6 ng/L, and the average recoveries were 41-111% for the nine nitrosamines; of these, NDMA, N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip), and N-nitrosodiphenylamine (NDPhA) were identified and quantified in drinking water samples collected from four locations within the same distribution system. In general, the concentrations of these four nitrosamines in this distribution system increased with increasing distance from the water treatment plant, indicating that the amount of formation was greater than the amount of decomposition within this time frame. The identification of NPip and NDPhA in drinking water systems and the distribution profiles of these nitrosamines have not been reported previously. These nitrosamines are toxic, and their presence as DBPs in drinking water may have toxicological relevance.

Broad range analysis of endocrine disruptors and pharmaceuticals using gas chromatography and liquid chromatography tandem mass spectrometry

Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) have been globally detected in impacted natural waters. The detection of trace quantities of EDCs and PPCPs in the environment is of great concern since some of these compounds have known physiological responses at low concentrations. EDCs can have a wide range of polarities, acidic and basic moieties, and exist in trace quantities, which often requires numerous complex extractions, large sample collection volumes, and multiple instrumental analyses. A comprehensive method has been developed allowing for the analysis of 58 potential EDCs in various water matrices using a single solid-phase extraction (SPE) of a 1L sample with subsequent analyses using both gas chromatography and liquid chromatography, each coupled with tandem mass spectrometry (GC-MS/MS and LC-MS/MS). Instrument detection limits ranged between 0.12-7.5 pg with corresponding method reporting limits of 1-10 ng l(-1) in water. Recoveries for most compounds were between 50% and 112% with good reproducibility (RSD 6-22%).

On-line immunoaffinity column-liquid chromatography–tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample

An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC-MS/MS) method for the determination of diuron in water matrices was described. This method used a sol-gel immunoaffinity column (20 mm x 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm x 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy ( approximately 90% of recovery) and precision (<6% of relative standard deviation) at 50 ng/L concentration were also obtained. Due to the ability of the sol-gel immunoaffinity column to eliminate matrix effect, the on-line IAC-LC-MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.

Analysis of pesticides in water by liquid chromatography-tandem mass spectrometric techniques

Pesticide residues continue to be the focus of many environmental studies, and the number of articles describing the development of more advanced, multiresidue analytical methodologies does not decline. The use of liquid chromatography-mass spectrometry based on single quadrupole or ion trap analyzers is consolidated for this purpose. The implementation, in the near future, of more sophisticated mass analyzers, such as triple quadrupole and hybrid quadrupole-time-of-flight is anticipated for routine analysis. This article reviews the various works published so far in the literature for the determination of pesticides and transformation products (TPs) in water by means of liquid chromatography (LC) coupled to tandem mass spectrometry. It discusses the various ionization sources and analyzers used for this purpose, as well as the extraction procedures employed for previous sample preconcentration. Because of the widespread use of triple quadrupole analyzers for the generation of pesticides levels in water using tandem mass spectrometry, a table compiling the transitions monitored for ca. 70 compounds is also included.

Potential of liquid chromatography/time-of-flight mass spectrometry for the determination of pesticides and transformation products in water

Until now, time-of-flight (TOF) mass analysers have only been very rarely used in pesticide residue analysis (PRA) of water samples. However, the inherent characteristics of TOF MS make these analysers well-suited to this field, mainly for qualitative purposes. Thus, the high sensitivity obtained from full-scan acquisition in comparison to other MS analysers and the high resolution of TOF MS suggest its suitability for screening purposes; it also increases the multiresidue capabilities of methods based on it and decreases the chance of recording false positives. Although these characteristics can also be helpful for quantification, confirmation and elucidation, some limitations on the use of TOF for these purposes have been observed. These limitations are more noticeable when dealing with samples containing very low analyte concentrations, which is the normal situation for PRA in water. The use of hybrid quadrupole-time-of-flight instruments (QTOF) minimises the limitations of TOF, facilitating the simultaneous detection and unequivocal confirmation of pesticides found in the sample. Additionally, the acquisition of accurate product ion full-scan mass spectra can help to elucidate the structures of unknown compounds. In this paper, the potential of TOF and QTOF hyphenated to liquid chromatography for PRA in water is explored, emphasizing both the advantages and limitations of this approach for screening, quantification, confirmation and elucidation purposes. Emphasis is placed on the determination of polar pesticides and transformation products-the analytes that fit well with LC-API-(Q)TOF MS technology.

Efficient approach for the reliable quantification and confirmation of antibiotics in water using on-line solid-phase extraction liquid chromatography/tandem mass spectrometry

The potential of solid-phase extraction coupled on-line to liquid chromatography/electrospray tandem mass spectrometry (SPE-LC-ESI-MS/MS) has been investigated in this paper for the efficient sensitive quantification and confirmation of 16 antibiotics in water. The list of targeted analytes included 10 quinolones (oxolinic acid (OXO), nalidixic acid (NAL), flumequine (FLU), marbofloxacine (MAR), ofloxacine (OFLO), enrofloxacine (ENR), pefloxacine (PEF), ciprofloxacine (CIP), pipemidic acid (PIPE), norfloxacine (NOR)) and 6 penicillins (penicillin G (PEN), oxacillin (OXA), dicloxacillin (DIC), piperacillin (PIP), cloxacillin (CLO) and ampicillin (AMP)) that were determined in ground and surface water. The procedure is based on the injection of 9.8 mL of sample into the SPE-LC-MS/MS system and the measurement of antibiotics by selected reaction monitoring mode, using a triple quadrupole analyser. The method has been validated at realistic low concentrations that might be present in environmental water, i.e. 10 and 100 ng L(-1), obtaining recoveries between 74% and 123% with relative standard deviation lower than 14%. Matrix effects were not relevant in most of cases, except for ampicillin in surface water, where notable signal suppression was observed. The limits of detection were as low as 0.4-4.3 ng L(-1). The method developed allows the rapid screening and quantification of all the analytes selected by acquiring one MS/MS transition (normally the most sensitive) for each compound. It was applied to a number of actual surface and groundwater samples with several compounds being detected, mainly quinolones, at low ng L(-1) levels. Special attention was given to the confirmation of compounds detected in water due to the difficulties of obtaining confident confirmation at low ng L(-1). This matter has been of growing concern in the last few years as reflected by recent papers and correspondence. The acquisition of several MS/MS transitions for each compound detected in a second independent analysis allowed the unequivocal confirmation of identity, avoiding reporting false-positives. Finally, the potential of QTOF instruments to confirm positive samples has also been evaluated and compared with triple quadrupole analysers.

Identification of anionic supramolecular complexes of sulfonamide receptors with Cl-, NO3-, Br-, and I- by APCI-MS

As part of a mass spectrometric investigation of the binding properties of sulfonamide anion receptors, an atmospheric pressure chemical ionization mass spectrometric (APCI-MS) method involving direct infusion followed by thermal desorption was employed for identification of anionic supramolecular complexes in dichloromethane (CH2Cl2). Specifically, the dansylamide derivative of tris(2-aminoethyl)amine (tren) (1), the chiral 1,3-benzenesulfonamide derivatives of (1R,2S)-(+)-cis-1-amino-2-indanol (2), and (R)-(+)-bornylamine, (3), were shown to bind halide and nitrate ions in the presence of (n-Bu)4N+X- (X- = Cl-, NO3-, Br-, I-). Solutions of receptors and anions in CH2Cl2 were combined to form the anionic supramolecular complexes, which were subsequently introduced into the mass spectrometer via direct infusion followed by thermal desorption. The anionic supramolecular complexes [M + X]-, (M = 1-3, X- = Cl-, NO3-, Br-, I-) were observed in negative mode APCI-MS along with the deprotonated receptors [M - H]-. Full ionization energy of the APCI corona pin (4.5 kV) was necessary for obtaining mass spectra with the best signal-to-noise ratios.

Current literature in mass spectrometry

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (5 Weeks journals ‐ Search completed at 8th. Sept. 2004)