Multi-residue analytical method for human pharmaceuticals and synthetic hormones in river water and sewage effluents by solid-phase extraction and liquid chromatography–tandem mass spectrometry

Pollutants such as human pharmaceuticals and synthetic hormones that are not covered by environmental legislation have increasingly become important emerging aquatic contaminants. This paper reports the development of a sensitive and selective multi-residue method for simultaneous determination and quantification of 23 pharmaceuticals and synthetic hormones from different therapeutic classes in water samples. Target pharmaceuticals include anti-diabetic, antihypertensive, hypolipidemic agents, β2-adrenergic receptor agonist, antihistamine, analgesic and sex hormones. The developed method is based on solid phase extraction (SPE) followed by instrumental analysis using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC–ESI-MS/MS) with 30 min total run time. River water samples (150 mL) and (sewage treatment plant) STP effluents (100 mL) adjusted to pH 2, were loaded into MCX (3 cm³, 60 mg) cartridge and eluted with four different reagents for maximum recovery. Quantification was achieved by using eight isotopically labeled internal standards (I.S.) that effectively correct for losses during sample preparation and matrix effects during LC–ESI-MS/MS analysis. Good recoveries higher than 70% were obtained for most of target analytes in all matrices. Method detection limit (MDL) ranged from 0.2 to 281 ng/L. The developed method was applied to determine the levels of target analytes in various samples, including river water and STP effluents. Among the tested emerging pollutants, chlorothiazide was found at the highest level, with concentrations reaching up to 865 ng/L in STP effluent, and 182 ng/L in river water.     

Using subcritical/supercritical fluid chromatography to separate acidic,basic, and neutral compounds over an ionic liquid-functionalized stationary phase

We packed an ionic liquid (IL)-functionalized stationary phase – based on 1-octyl-3-propylimidazolium chloride covalently bounded to silica gel – into a 3.2 mm × 250 mm column for the simultaneous separation of acidic, basic, and neutral compounds using carbon dioxide subcritical/supercritical fluid chromatography (SFC), and examined the effects of the pressure, temperature, co-solvents, and additives on the retention behavior of the analytes. The model compounds tested for SFC separation are acetaminophen, metoprolol, fenoprofen, ibuprofen, naphthalene, and testosterone. The data indicate that hydrogen-bonding and hydrophobic interactions between the analytes and the IL-modified stationary phase seem to involve in the separation process. Simultaneous separation of acidic, basic, and neutral compounds via SFC was successful at a co-solvent content of 20% MeOH, a pressure of 110 bar, and a column temperature of 35 °C. The relative standard deviations of the retention times and peak areas at 50 ppm were all less than 4 and 8% (n = 6), respectively.     

Development of a multi-residue analytical method,based on liquid chromatography–tandem mass spectrometry,for the simultaneous determination of 46 micro-contaminants in aqueous samples

A multi-residue analytical method based on high-performance liquid chromatographic separation, electrospray ionization with tandem mass spectrometric detection (HPLC/MS–MS) was developed for the simultaneous analysis of 46 basic, neutral and acidic compounds covering a wide range of polarity (log K_OW < 0–5.9). The compound list included selected iodinated contrast media, analgesics, anti-inflammatories, stimulants, beta-blockers, antibiotics, lipid regulators, anti-histamines, psychiatric drugs, herbicides, corrosion inhibitors and the gastric acid regulator pantoprazole. The main feature of the presented method was a simultaneous solid phase extraction (SPE) of all analytes followed by simultaneous separation and detection by HPLC/MS–MS with electrospray ionization in both positive and negative polarization within the same chromatogram. Optimization of electrospray drying gas temperature resulted in using a temperature gradient on the ion source. Six different polymeric sorbents for SPE were compared with respect to recoveries, taking into account the specific surface of each sorbent. Method quantitation limits (MQL) in surface and seawater ranged from 1.2 to 28 ng/L, in wastewater from 5.0 to 160 ng/L, respectively. In order to demonstrate the applicability of the method, river water, treated wastewater and seawater were analyzed.     

Application of silica-based monolith as solid phase extraction cartridge for extracting polar compounds from urine

The silica monolith with ionizable silanol groups and large surface area was found able to function as an offline cation exchange solid phase extraction (SPE) cartridge for extracting polar analytes. The prepared cartridge was housed in a 2-mL syringe fixed over a SPE vacuum manifold. The unique property of this silica monolithic cartridge was demonstrated by extracting epinephrine, normetanephrine and metanephrine from urine samples. These analytes were chosen as model compounds for testing because of their high hydrophilicity, and being candidates monitored for clinical diagnosis. The extracted analytes, after concentration and reconstitution were then quantitated by high-performance liquid chromatography coupled to mass spectrometer (HPLC/ESI/MS). Multiple reactions monitoring was carried out with transitions: 184 → 107, 184 → 134 and 198 → 148 for analyzing epinephrine, normetanephrine and metanephrine, respectively. The limit of detection was 3 ng/mL for metanephrine and 5 ng/mL for normetanephrine and epinephrine. The relative standard deviations of measurements ranged from 2 to 10%. The sorbent offered good linearity with coefficient of determination (r²) > 0.99, over a concentration range of 20-200 ng/mL. The relative recoveries ranged from 60 to 67%, 55 to 59% and 99 to 105% for epinephrine, normetanephrine and metanephrine, respectively. The prepared cartridge had shown potential and was found robust in extracting the polar analytes repeatedly without any significant loss in efficiency.     

Pharmaceutical determination in surface and wastewaters using high-performance liquid chromatography-(electrospray)-mass spectrometry

A method was developed to determine 11 pharmaceutical compounds in water samples. The method uses SPE and HPLC coupled to MS (LC/MS) using ESI in both positive and negative modes. Three different sorbents were compared for the extraction of analytes from river and sewage treatment plant (STP) waters and OASIS HLB provided the best results. For the solid-phase extraction of 500 mL of river water samples, the recoveries were between 41 and 101% with the exception of acetaminophen, salicylic acid and naproxen. The LODs were between 3 and 5 ng/L for all the compounds, except naproxen which had an LOD of 15 ng/L. Acetaminophen, caffeine, carbamazepine, bezafibrate and ibuprofen were found in three of the tested river samples at ng/L levels and among them, the highest values were for caffeine and bezafibrate with 305 and 363 ng/L, respectively. For the influent and effluent water samples of the STP, volumes of 100 and 250 mL were used, respectively, to obtain acceptable recoveries. All the compounds showed recoveries between 33 and 91% for effluent samples and 33-72% for influent samples, with the exception of acetaminophen, salicylic acid and bezafibrate, which had lower recoveries. The method developed enabled pharmaceuticals in the influent and effluent sewage waters to be determined in five campaigns carried out between February 2004 and June 2005. Several pharmaceuticals were found in the influent samples: for instance, maximum concentrations of ibuprofen and caffeine were 6 and 40 microg/L, respectively.     

Application of dynamic liquid-phase microextraction and injection port derivatization combined with gas chromatography–mass spectrometry to the determination of acidic pharmaceutically active compounds in water samples

A method has been established for the determination of four pharmaceutically active compounds (ibuprofen, ketoprofen, naproxen and clofibric acid) in water samples using dynamic hollow fiber liquid-phase microextraction (HF/LPME) followed by gas chromatography (GC) injection port derivatization and GC–mass spectrometric (MS) determination. Dynamic HF/LPME is a novel approach to microextraction that involves the use of a programmable syringe pump to move the liquid phases participating in the extraction so as to facilitate the process. Trimethylanilinium hydroxide (TMAH) was used as derivatization reagent for the analytes to increase their volatility and improve chromatographic separation. Parameters that affect extraction efficiency (selection of organic solvent, volume of organic solvent, agitation in the donor phase, plunger movement and extraction time) were investigated. Under optimal conditions, the proposed method provided good enrichment factors up to 251, reproducibility ranging from 3.26% to 10.61%, and good linearity from 0.2 to 50 μg/L. The limits of detection ranged between 0.01 and 0.05 μg/L (S/N = 3) using selective ion monitoring. This method was applied to the determination of the four pharmaceutically active compounds in tap water and wastewater collected from a drain in the vicinity of a hospital.     

Simple assay for monitoring seven quinolone antibacterials in eggs: Extraction with hot water and liquid chromatography coupled to tandem mass spectrometry: Laboratory validation in line with the European Union Commission Decision 657/2002/EC

A simple and rapid method able to determine residues of seven quinolone antibacterials in whole eggs is presented here. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography–tandem mass spectrometry. After depositing 1.5 g of an egg sample containing the analytes and the analyte surrogate (norfloxacin) on sand (crystobalite), this material was packed into an extraction cell. Quinolones were extracted by flowing 6 mL of water acidified with 50 mmol/L formic acid through the cell heated at 100 °C. After pH adjustment and filtration of the extract, 100 μL of it was injected into the LC column. MS data acquisition was performed in the multiple reaction monitoring mode, selecting two precursor ion to product ion transitions for each target compound. Hot water appeared an efficient extracting medium, since absolute recoveries of the analyte in egg at the level of 20 ng/g were 89–103%. Estimated limits of quantification (S/N = 10) were 0.2–0.6 ng/g. Based on the EU Commission Decision 2002/657/EC, the method was validated in terms of ruggedness, specificity, linearity, within-laboratory reproducibility, decision limit (CCα and detection capability (CCβ). Depending on the particular analyte, CCαs ranged between 0.41 and 2.6 ng/g, while CCβs were 0.64–3.7 ng/g. The method was linear in the 3–30 ng/g range, with typical R² values higher than 0.97. The within-laboratory reproducibility (n = 21) at 6 ng/g level was in the 9.0–12% range. After validation, a depletion study of enrofloxacin and one of its metabolites, i.e. ciprofloxacin, in eggs was conducted.     

Plastified poly(ethylene terephthalate) (PET)-toner microfluidic chip by direct-printing integrated with electrochemical detection for pharmaceutical analysis

Rapid separation and determination of acetaminophen and its hydrolysate with end-channel electrochemical (EC) detection integrated on a plastified poly(ethylene terephthalate) (PET)-toner microchip capillary electrophoresis (CE) system was investigated. In this separation and detection system, a Pt ultramicroelectrode integrated on a three-dimensional adjustor was used as working electrode. Factors influencing the separation and detection were investigated and optimized. Results show that acetaminophen and p-aminophenol can be well separated within 84 s with R.S.D. < 1% for migration time and R.S.D. < 3.6% for detection current for both analytes. Detection limits for both analytes are determined to be 5.0 μM (S/N = 3). This method has been successfully applied to the detection of trace p-aminophenol in paracetamol tablets. The results demonstrate that the PET-toner microchips can obtain better performance than PDMS microfluidic devices but at much lower cost.     

Determination of drugs of abuse in water by solid-phase extraction,derivatisation and gas chromatography–ion trap-tandem mass spectrometry

An alternative method for the sensitive determination of several drugs of abuse and some of their metabolites in surface and sewage water samples is proposed. Analytes are concentrated using a solid-phase extraction (SPE) sorbent, converted into the corresponding trimethylsilyl derivatives and selectively determined by gas chromatography (GC) with tandem mass spectrometry (MS/MS) detection. Parameters affecting the performance of extraction, derivatisation and determination steps are systematically investigated. Moreover, the stability of target analytes in sewage water samples is discussed. Under final working conditions, water samples were adjusted at pH 8.5 and concentrated using a 200 mg OASIS HLB SPE cartridge. Analytes were sequentially eluted with ethyl acetate followed by acetone and silylated using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA). The reaction was completed in 60 min at 80 °C and the mixture injected directly in the GC–MS/MS system without further purification. In most cases, analytes presented a poor stability in sewage water samples; however, once they are submitted to the SPE process, cartridges can be stored at −20 °C for at least 3 months without significant degradation and/or inter-conversion reactions of illicit drugs. The proposed method provided recoveries over 74% and LODs between 0.8 and 15 ng/L for river and treated wastewater samples. In the case of raw wastewater slightly worse recoveries, between 63 and 137%, and similar LODs were attained. Analysis of a limited number of waste and surface water samples confirmed the presence of several illicit drugs in the aquatic environment, with the highest levels and frequency corresponding to benzoylecgonine, the main metabolite of cocaine.     

Gas–liquid chromatography–tandem mass spectrometry methodology for the quantitation of estrogenic contaminants in bile of fish exposed to wastewater treatment works effluents and from wild populations

Fish can be exposed to a complex mixture of chemical contaminants arising from the exposure to wastewater treatment works (WwTWs) effluents. Some of these contaminants are estrogenic and have been associated with feminisation of male fish and the presence of populations containing intersex individuals. However the detection of trace levels (ng/L) of estrogenic chemicals surface waters can be difficult and does not give information on the exposure of aquatic organisms to these contaminants. In this study we assessed whether the analysis of estrogenic substances that bioconcentrate in fish bile can be used to detect the exposure of fish to feminising contaminants in receiving waters and effluents, and thus facilitate their monitoring of these substances in aquatic environments. Estrogenic metabolites in bile were deconjugated using enzymatic hydrolysis and partially purified by solid phase extraction. Steroidal and xenoestrogens were derivatized to their trimethylsilyl ethers and quantified by gas–liquid chromatography–mass spectrometry (GC–MS/MS) using multiple reaction monitoring. The method was validated using spiked bile samples from immature female rainbow trout (Oncorhynchus mykiss) as well as bile from sexually mature roach (Rutilus rutilus) that had been exposed to either tap water or an undiluted estrogenic effluent for 10 days or captured from a river site downstream of a WwTWs effluent discharge. The mean recovery of target analytes from spiked bile was between 86 and 99% and the limit of detection was between 0.1 and 0.7 ng/mL bile for bisphenol A (BPA), 17β-estradiol (E2), estrone (E1) and 17α-ethinylestradiol (EE2), and 11, 60 and 327 ng/mL bile for branched nonyl chain isomeric mixtures of 4-nonylphenolethoxylate (NP1EO), 4-nonylphenol (NP) and 4-nonylphenoldiethoxylate (NP2EO), respectively. All target analytes were detected in bile from roach exposed directly to a WwTWs effluent, with concentrations between 6–13 μg/mL bile for NP, 18–21 μg/mL for NP1EO, 75–135 μg/mL for NP2EO, 0.7–2.5 μg/mL for BPA, E2 and E1 and 17–29 ng/mL for EE2. With the exception of NP2EO, all analytes were detected in at least 2 out of the 5 fish sampled from the River Thames. BPA and NP1EO were detected in all three reference fish held in tap water indicating possible contamination from laboratory plastics. The work shows that analysis of 20–100 μL quantities of bile could be a useful approach in detecting exposure to mixtures of estrogenic contaminants taken up by fish from WwTW effluents and has the potential for monitoring the efficacy of remediation strategies that may be adopted for reduction of these endocrine disrupting chemicals in the aquatic environment.     

Further research on the photo-SPME of triclosan

In this study the photoinduced degradation of triclosan has been investigated by photo-solid-phase microextraction (photo-SPME). In photo-SPME, photodegradation is carried out on the SPME fibre containing the target compound. Triclosan was extracted from aqueous solutions by use of polydimethylsiloxane SPME fibres and these were subsequently exposed to UV irradiation (power 8 W, wavelength 254 nm) for different times (from 2 to 60 min). The photodegradation kinetics of triclosan were investigated, the photoproducts generated were tentatively identified, and the photochemical behaviour of these products was studied by use of this on-fibre approach followed by gas chromatographic–mass spectrometric analysis. Eight photoproducts were tentatively identified, including chlorinated phenols, chlorohydroxydiphenyl ethers, 2,8-dichlorodibenzo-p-dioxin, and a possible dichlorodibenzodioxin isomer or dichlorohydroxydibenzofuran. The main photodegradation mechanisms were postulated and photodegradation pathways proposed. The effect of pH on triclosan degradation and on triclosan-to-dioxin conversion was also investigated. Triclosan degradation occurred, and generation of 2,8-dichlorodibenzo-p-dioxin was confirmed, throughout the pH range studied (from 3 to 9).      

On-column liquid–liquid–liquid microextraction coupled with base stacking as a dual preconcentration method for capillary zone electrophoresis

A simple and efficient dual preconcentration method of on-column liquid–liquid–liquid microextraction (LLLME) coupled with base stacking was developed for capillary zone electrophoresis (CZE) in this paper. Four N-methyl carbamates were used as target compounds to evaluate the enrichment means. The carbamates in sample solutions (donor phase) were extracted into a dodecanol phase immobilized on a porous hollow fiber, hydrolyzed and back extracted into 0.20 μL running buffer (acceptor phase) of 30 mmol/L methylamine hydrochloride (pH 11.6) containing 0.5 mmol/L tetradecyltrimethylammonium bromide inside the hollow fiber, stacked further with 0.5 mol/L NaOH injected at −10 kV for 60 s, and separated by CZE. Analytical parameters affecting the LLLME, base stacking and CZE were investigated, including sample solution volume, pH and temperature, extraction time, stirring rate, buffer component, buffer pH, NaOH concentration, stacking time, etc. The enrichment factors of the carbamates were higher than 1100. The relative standard deviation (RSD) of peak height and limits of detection (LODs) were 4.5–5.5% (n = 6) and 2–4 ng/mL (S/N = 3) for standard solutions, respectively. The proposed method was applied to the analysis of vegetable and fruit samples with the RSD less than 6.0% (n = 3) and LODs of 6–10 ng/g (S/N = 3). The calibration solutions were prepared by diluting the stock solutions with blank sample solutions, and the calibration concentrations ranged from 0.012 to 1.0 μg/mL (r > 0.9951). The analytical results demonstrated that the LLLME coupled with base stacking was a simple, convenient and reliable on-column sample pretreatment method for the analysis of anionic analytes in CZE.     

Targeted analysis with benchtop quadrupole–orbitrap hybrid mass spectrometer: Application to determination of synthetic hormones in animal urine

Sensitive and unequivocal determination of analytes/contaminants in complex matrices is a challenge in the field of food safety control. In this study, various acquisition modes (Full MS/AIF, Full MS + tMS/MS, Full MS/dd MS/MS and tSIM/ddMS/MS) and parameters of a quadrupole–orbitrap hybrid mass spectrometer (Q Exactive) were studied in detail. One of the main conclusions has been that, reducing the scan range for Full MS (using the quadrupole) and targeted modes give higher signal-to-noise (S/N) ratios and thereby better detection limits for analytes in matrix. The use of Q Exactive in a complex case, for the confirmatory analysis of hormones in animal urine is presented. A targeted SIM data dependent MS/MS (tSIM/ddMS/MS) acquisition method for determination of eight synthetic hormones (trenbolone, 17α ethinylestradiol, zeranol, stanozolol, dienestrol, diethylstilbestrol, hexestrol, taleranol) and a naturally occurring hormone (zearalenone) in animal urine were optimized to have sensitive precursors from targeted SIM mode and trigger MS/MS scans over the entire chromatograph peak. The method was validated according to EC/657/2002. CCα (decision limit) for the analytes ranged between 0.11 μg L⁻¹ and 0.69 μg L⁻¹ and CCβ (detection capability) ranged between 0.29 μg L⁻¹ and 0.90 μg L⁻¹.     

Optimization of some experimental parameters in the electro membrane extraction of chlorophenols from seawater

An electro membrane extraction (EME) methodology was utilized to study the isolation of some environmentally important pollutants, such as chlorophenols, from aquatic media based upon the electrokinetic migration process. The analytes were transported by application of an electrical potential difference over a supported liquid membrane (SLM). A driving force of 10 V was applied to extract the analytes through 1-octanol, used as the SLM, into a strongly alkaline solution. The alkaline acceptor solution was subsequently analyzed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. The parameters influencing electromigration, including volumes and pH of the donor and acceptor phases, the organic solvent used as the SLM, and the applied voltage and its duration, were investigated to find the most suitable extraction conditions. Since the developed method showed a rather high degree of selectivity towards pentachlorophenol (PCP), validation of the method was performed using this compound. An enrichment factor of 23 along with acceptable sample clean-up was obtained for PCP. The calibration curve showed linearity in the range of 0.5–1000 ng/mL with a coefficient of estimation corresponding to 0.999. Limits of detection and quantification, based on signal-to-noise ratios of 3 and 10, were 0.1 and 0.4 ng/mL, respectively. The relative standard deviation of the analysis at a PCP concentration of 0.5 ng/mL was found to be 6.8% (n = 6). The method was also applied to the extraction of this contaminant from seawater and an acceptable relative recovery of 74% was achieved at a concentration level of 1.0 ng/mL.     

Determination of fecal sterols by gas chromatography–mass spectrometry with solid-phase extraction and injection-port derivatization

Injection-port derivatization combined with solid-phase extraction (SPE) was developed and applied for the first time to determine five types of fecal sterols (coprostanol, cholestanol, epicholestanol, epicoprostanol and cholesterol) with gas chromatography–mass spectrometry (GC–MS). In this method, silylation of fecal sterols was performed with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) at GC injection-port. The factors influential to this technique such as injection-port temperature, purge-off time, derivatization reagent (BSTFA) volume, and the type of organic solvent were investigated. In addition, the conditions of SPE (including the type of SPE cartridge, the type of elution organic solvent) were also studied. After SPE followed by injection-port silylation by GC–MS, good linearity of analytes was achieved in the range of 0.02–10 ng/mL with coefficients of determination, R² > 0.995. Good reproducibility was obtained with relative standard deviation less than 19.6%. The limits of detection ranged from 1.3 ng/mL to 15 ng/mL (S/N = 3) in environmental water samples. Compared with traditional off-line silylation of fecal sterols performed with water bath (60 °C, 30 min), this injection-port silylation method is much simpler and convenient. The developed method has been successfully applied for the analysis of fecal sterols from real environmental water samples.     

Ultra-high-performance liquid chromatography–tandem mass spectrometry for determining the presence of eleven personal care products in surface and wastewaters

Personal care products (PCPs) are widely used emerging contaminants which can cause adverse environmental effects. This paper reports the development and validation of a method based on solid-phase extraction (SPE) and ultra-high-performance liquid chromatography–electrospray ionisation–tandem mass spectrometry (UHPLC–(ESI)MS–MS) for simultaneously determining eleven PCPs: 4 preservatives (methylparaben; ethylparaben; benzylparaben; propylparaben); 2 antimicrobial agents (triclocarban and triclosan) and 5 UV filters (2,4-dihydroxybenzophenone; 2,2-dihydroxy-4-methoxybenzophenone; benzophenone-3; octocrylene and octyldimethyl-p-aminobenzoic acid) in environmental waters in only 9 run minutes of chromatographic separation. The SPE was carried out with two polymeric cartridges (Oasis HLB and Bond Elut Plexa). The recoveries obtained with Bond Elut Plexa were between 69% and 101% for 500 mL of river waters, with the exception of octyldimethyl-p-aminobenzoic acid (46%). Limits of detection for 500 mL of river water were in the range of 1–5 ng/L. Oasis HLB was chosen for wastewater samples with recoveries between 38% and 92% (250 mL of effluents) and 36–89% (100 mL of influents). In both wastewater samples, octyldimethyl-p-aminobenzoic acid and methylparaben showed the lowest recoveries (20% and 27%). The method revealed benzophenone-3 as having the highest concentration levels (7 ng/L) in river waters. Most of PCPs determined were found in influent waters being methylparaben and propylparaben the ones found at highest concentration with values of 5613 and 1945 ng/L, respectively. In effluent waters, significant lower levels of some PCPs were found, being benzophenone-3 the one found at the highest concentration (100 ng/L).     

Simultaneous determination of 15 steroidal oral contraceptives in water using solid-phase disk extraction followed by high performance liquid chromatography–tandem mass spectrometry

A rapid, accurate and sensitive method for simultaneous determination of 15 steroidal hormones including four estrogens (estrone, 17β-estradiol, 17α-ethynylestradiol, estriol) and eleven progestogens (17β-estradiol-3-benzoate, 19-norethindrone, gestodene, levonorgestrel, medroxyprogesterone, cyproterone acetate, megestrol-17-acetate, progesterone, norethindrone acetate, chlormadinone-17-acetate, and hydroxy progesterone caproate) in environmental waters was developed by coupling solid-phase disk extraction (SPDE) to ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) with electrospray ionization. Among three types of extraction tested (C₈ SPDE, C₁₈ SPDE and C₁₈ SPE), the most satisfactory result was achieved using C₁₈ SPDE for its satisfactory recovery (75.6 to 101.4%) and short extraction time (15 min for 1 L deionised water). The validity of this method was investigated and good analytical performance for all the analytes was obtained, including low limits of method detection (0.5–3.4 ng/L) and excellent linear dynamic range (1.0–50.0 ng/L). The method was applied to determine the steroidal hormones in 10 environmental waters including tap water, river water, lake water and waste water in Beijing. No progestogen was detected in all samples and estrone, estriol, 17α-ethynylestradiol were found in most samples at levels between 1.8 and 127.9 ng/L.     

Determination of pyridine, 2-picoline, 4-picoline and quinoline from mainstream cigarette smoke by solid-phase extraction liquid chromatography/electrospray ionization tandem mass spectrometry

The present paper describes the development and validation of a new reversed-phase liquid chromatography–electrospray ionization tandem mass spectrometric method (RP-HPLC–ESI-MS/MS) for simultaneous determination of pyridine, 2-picoline, 4-picoline and quinoline from mainstream cigarette smoke. Liquid–liquid extraction followed by solid-phase extraction was applied to extract the target analytes from cigarette smoke. Baseline chromatographic separation was achieved by utilizing a Zorbax SB-Aq (4.6 × 150 mm, 5 μm) column in gradient chromatographic conditions with acetonitrile and ammonium acetate buffer as mobile phases. Popular commercially available Indian brand filtered and non-filtered cigarettes were analyzed using the same method. The identification of each chemical was established by chromatographic retention times, analyte specific fragmentation patterns and relative peak area ratios of two product/precursor ion pairs. The limit of detection of this method ranged from 1.74 to 14.32 ng/cig using an injection volume of 20 μl. The reproducibility of this method is excellent and better standard deviations were obtained compared to literature reported values for these chemicals. RSD value is less than 9% for all analytes.     

Gel permeation chromatography clean-up for the determination of gestagens in kidney fat by liquid chromatography–tandem mass spectrometry and validation according to 2002/657/EC

A specific and sensitive method based on liquid chromatography–tandem mass spectrometry using atmospheric pressure chemical ionization (LC–APCI–MS/MS) has been developed for the determination of gestagens in kidney fat (medroxyprogesterone acetate, megestrol acetate and melengestrol acetate). The procedure involved a clean-up procedure with gel permeation chromatography (GPC). The analytes were analyzed by reversed-phase LC–MS/MS, in positive multiple reaction monitoring (MRM) mode, acquiring two diagnostic product ions from the chosen precursor for the unambiguous confirmation of the gestagens. The method was validated at the validation level of 1.0 ng/g. The accuracy and precision of the method were satisfactory. The decision limits CCα ranged from 0.20 to 0.22 ng/g while the detection capabilities CCβ ranged from 0.33 to 0.38 ng/g. The method proved to be sensitive and reliable and thus renders an appropriate mean for residue analysis studies.     

Determination of fluoroquinolones in environmental waters by in-tube solid-phase microextraction coupled with liquid chromatography-tandem mass spectrometry

We developed a sensitive and useful method for the determination of five fluoroquinolones (FQs), enoxacin, ofloxacin, ciprofloxacin, norfloxacin, and lomefloxacin in environmental waters, using a fully automated method consisting of in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS). These compounds were analysed within 7 min by high-performance liquid chromatography (HPLC) using a CAPCELL PAK C8 column and aqueous ammonium formate (pH 3.0, 5 mM)/acetonitrile (85/15, v/v) at a flow rate of 0.2 mL/min. Electrospray ionization conditions in the positive ion mode were optimized for MS/MS detection. In order to optimize the extraction of FQs, several in-tube SPME parameters were examined. The optimum in-tube SPME conditions were 20 draw/eject cycles of 40 μL of sample at a flow-rate of 150 μL/min, using a Carboxen 1010 PLOT capillary column as an extraction device. The extracted compounds were easily desorbed from the capillary by passage of the mobile phase. Using the in-tube SPME LC/MS/MS method, good linearity of the calibration curve (r ≥ 0.997) was obtained in the concentration range from 0.1 to 10 ng/mL for all compounds examined. The limits of detection (S/N = 3) of the five FQs ranged from 7 to 29 pg/mL. The in-tube SPME method showed 60-94-fold higher sensitivity than the direct injection method (5 μL injection). This method was applied successfully to the analysis of environmental water samples without any other pretreatment and interference peaks. Several surface waters and wastewaters were collected from the area around Asahi River, and ofloxacin was detected in wastewater samples of a sewage treatment plant and other two hospitals at 17.5-186.2 pg/mL. The recoveries of FQs spiked into river water were above 81% for a 0.1 or 0.2 ng/mL spiking concentration, and the relative standard deviations were below 1.9-8.6%.