Municipal Wastewater Samples Research Articles

Quantitative detection of trace mercury in environmental media using a three-dimensional electrochemical sensor with an anionic intercalator

Mercury, one of the most widespread highly toxic heavy metals, has severe detrimental effects on human health and the environment. It is significant to develop a sensitive and reliable method of accurately detecting trace levels of mercuric ions in environmental media to meet the ever-increasing demands of ongoing environmental monitoring programs. A three-dimensional mercuric ion sensor was constructed using mercury-specific oligonucleotides, gold nanoclusters, and an anionic intercalator. Due to the steric reaction field in the electrode surface microenvironment formed by the gold nanoclusters, the sensor could spatially capture mercuric ions with electroactive indication to realize trace mercury measurements with high sensitivity; the sensor exhibited strong environmental adaptability, high selectivity, and other advantages. Under optimal conditions, mercuric ions could be detected in the range from 0.05 to 350 nM, and the detection limit was 0.01 nM. The mercuric ion sensor was compared with atomic fluorescence spectrometry to analyze municipal wastewater and river water samples. In addition, the sensor performance was also analyzed according to derived formulae. This accurate method has the potential to be deployed in the field for measurements of mercury in environmental media.

Analysis of Estrogens in Wastewater Using Solid-Phase Extraction, QuEChERS Cleanup, and Liquid Chromatography/Tandem Mass Spectrometry

We present an improved method for trace level quantification of five estrogens including estriol, estrone, 17alpha-estradiol, 17beta-estradiol, and 17alpha-ethinylestradiol in wastewaters. Our method includes sample preparation using SPE followed by a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) cleanup step, a derivatization, and LC/MS/MS determination. Sample extraction was carried out using Oasis HLB cartridges and a dispersive solid-phase cleanup pack containing MgSO4 and primary-secondary amine and C18 sorbents. The resulting extract was derivatized with dansyl chloride. Separation was achieved on an Agilent Zorbax Extend C18, Narrow Bore RR 2.1 x 100 mm, 3.5 pm column; quantification was accomplished in the positive ion mode using multiple reaction monitoring. The cleanup method is quick, efficient, inexpensive, and requires only 200 mL of water. Reliable linearities were obtained for all calibration curves (r2 > 0.995). Matrix effects calculated were less than 12% for all analytes, and, hence, matrix matched calibration curves were not needed. The recoveries for the estrogens ranged from 81-103%, with a high repeatability (n = 3, RSD < or = 9%) and low LOQs (0.6-0.9 ng/L). The method was used to analyze effluent and influent wastewaters in Mississippi wastewater treatment plants, but it is broadly applicable for the determination of trace estrogens in any municipal wastewater samples.

Determination of 81 pharmaceutical drugs by high performance liquid chromatography coupled to mass spectrometry with hybrid triple quadrupole–linear ion trap in different types of water in Serbia

The aim of the work was to study the occurrence of pharmaceuticals in waste, surface, underground, and drinking water samples collected in Serbia. A multi-residue method for the analysis of 81 pharmaceutical drugs from different therapeutic classes in the various types of water was applied. Twenty-five composite water samples were prepared using solid-phase extraction and the presence of 81 pharmaceutical compounds in the extracts was analyzed by ultra-high performance liquid chromatography coupled to mass spectrometry with hybrid triple quadrupole–linear ion trap (UPLC–QqLIT–MS/MS). Forty seven compounds of 81 drugs were found in four different types of analyzed water. The highest concentrations of ibuprofen of 20.1μgL−1, 10,11-epoxycarbamazepine of 16.2μgL−1, 2-hydroxycarbamazepine of 15.9μgL−1 and acetaminophen of 15.7μgL−1 were found in municipal waste water sample. Results revealed the presence of salicylic acid in 41.67% of water samples, carbamazepine in 36.11%, propranolol and irbesartan in 30.56%. The obtained results were discussed in relation to the relevant data available in literature. This is the first attempt to assess the occurrence of these 81 pharmaceutical residues in water samples in Serbia.

Selected chloro and bromo derivatives of triclosan—syntheses and their occurrence in Canadian sewage and biosolid samples

The occurrence of triclosan (TCS), a general purpose antibacterial agent contained in numerous consumer and personal-care products, in the aquatic environment is well known. To a lesser degree, the formation of chlorinated and brominated derivatives of TCS during the chlorination of the antibacterial has also been reported. Presumably due to the lack of authentic standards, very few reports have been published on the levels of these halogenated TCSs in the environment. For this purpose, we have synthesized six selected halogenated derivatives of TCS, namely, 3-Cl-, 5-Cl-, 3,5-Cl2-, 3-Br-, 5-Br-, and 3,5-Br2- TCSs, with supporting (1)H-NMR (nuclear magnetic resonance) and GC-MS (gas chromatography-mass spectrometry) data for their structural assignments. Using these model compounds together with sensitive analytical methods, we were able to identify and quantify the above compounds together with their precursor compound TCS in Canadian municipal wastewater and biosolid samples for the first time. While detected in all influent (range from 1.4 to 24.1 ng L(-1)) and biosolid (range from 7.7 to 274 ng g(-1)) samples, the concentrations of these chlorinated TCS were generally from 100- to 1,000-fold lower than TCS in the same sample. Even lower levels (<20 ng/g in 85% of the results) of brominated TCS were found in biosolids, and they were mostly undetected in sewage.

On-line solid-phase microextraction of triclosan, bisphenol A, chlorophenols, and selected pharmaceuticals in environmental water samples by high-performance liquid chromatography–ultraviolet detection

A method using on-line solid-phase microextraction (SPME) on a carbowax-templated fiber followed by liquid chromatography (LC) with ultraviolet (UV) detection was developed for the determination of triclosan in environmental water samples. Along with triclosan, other selected phenolic compounds, bisphenol A, and acidic pharmaceuticals were studied. Previous SPME/LC or stir-bar sorptive extraction/LC-UV for polar analytes showed lack of sensitivity. In this study, the calculated octanol-water distribution coefficient (log D) values of the target analytes at different pH values were used to estimate polarity of the analytes. The lack of sensitivity observed in earlier studies is identified as a lack of desorption by strong polar-polar interactions between analyte and solid-phase. Calculated log D values were useful to understand or predict the interaction between analyte and solid phase. Under the optimized conditions, the method detection limit of selected analytes by using on-line SPME-LC-UV method ranged from 5 to 33 ng L(-1), except for very polar 3-chlorophenol and 2,4-dichlorophenol which was obscured in wastewater samples by an interfering substance. This level of detection represented a remarkable improvement over the conventional existing methods. The on-line SPME-LC-UV method, which did not require derivatization of analytes, was applied to the determination of TCS including phenolic compounds and acidic pharmaceuticals in tap water and river water and municipal wastewater samples.

Normalized Diurnal and Between-Day Trends in Illicit and Legal Drug Loads that Account for Changes in Population

Drug concentrations in composite municipal wastewater samples and census-based estimates of population are used to derive daily loads of illicit substances that are indexed to population. However, such estimates do not provide information on the diurnal trends of substance excretion nor can they account for changes in population. To address these limitations, a series of 1 h composites created by sampling wastewater influent at 6 min intervals was collected over four consecutive days at a single wastewater treatment plant. Creatinine (a urinary indicator), caffeine, methamphetamine, benzoylecgonine (BZE), and cocaine were analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). Diurnal trends and between-day trends were substance specific and related to the number of estimated doses and excretory half-life. Normalization to creatinine yielded trends in substances that differed significantly from non-normalized trends by accounting for changes in population within the municipality studied. Increases in normalized substance excretion observed during early morning hours originate from individuals among the resident population of the municipality due to the absence of commuters.

Quantitative analysis of methanol in wastewater by GC-MS with direct injection or headspace SPME sample introduction

Monitoring methanol (MeOH) concentration in wastewater treatment processes is important because methanol is a widely used carbon source for denitrification. Headspace solid-phase microextraction (HS-SPME) and direct liquid injection coupled with gas chromatography and mass spectrometry (GC/MS) were studied to analyze methanol in municipal wastewater samples in the μg mL−1 range. The conditions applied for both methods are presented. The extraction parameters for the HS-SPME method, such as SPME fiber selection, extraction temperature and time, agitation, pH value of the solution, and salt effect, were investigated. For the liquid injection method, the critical parameter was to select a polar column, the DB-WAX capillary column. Linear calibration curves were obtained over 3 orders of magnitude using methanol-d3 (MeOH-d3) or acetonitrile (ACN) as an internal standard. Both methods were validated with repeatability and recovery experiments. The liquid injection method requires a smaller injection volume and allows for faster analysis and better precision. The HS-SPME method also has reliable performance with less than 10% error. In addition, the comparison of the two methods on practical applications and maintenance is included.

A hydrolysis procedure for the analysis of total cocaine residues in wastewater

We report a sample pretreatment approach for the analysis of total cocaine residues in wastewater that eliminates the need for two key assumptions often made in estimating cocaine utilization from measurement of its benzoylecgonine metabolite: that benzoylecgonine is neither degraded nor generated during transport in a sewer system, and that it is excreted as a constant fraction of cocaine ingested. By adding NaOH and incubating samples at 55 °C, cocaine and its principal metabolites are efficiently hydrolyzed into ecgonine, anhydroecgonine, and norecgonine. Ecgonine, estimated to represent between 37% and 90% (on a molar basis) of cocaine residues, can be directly determined (without preconcentration via solid-phase extraction (SPE)) by reversed-phase (RP) or hydrophilic interaction liquid chromatography-tandem mass spectrometry (LC/MS/MS). If samples are subjected to SPE, anhydroecgonine can also be determined; this metabolite (and its precursors) represents ≈7% of urinary cocaine residues (based on spot collections from living individuals). Although a reference standard for norecgonine is not commercially available, such nortropanes are also a minor fraction (up to 2%) of urinary cocaine residues. The stability of two human markers (cotinine and creatinine) to the hydrolysis procedure was also investigated. Results obtained by applying the hydrolysis approach for the analysis of total cocaine in an untreated municipal wastewater sample (obtained from Baltimore, MD) were generally in excellent agreement with those obtained from split samples analyzed using a more comprehensive solid-phase extraction RPLC/MS/MS method as described in our previous work. In particular, total tropane-based cocaine residues were found to be hydrolyzed to ecgonine with 98-99% efficiency.

Bacteriophage Lysis of Enterococcus Host Strains: A Tool for Microbial Source Tracking?

This paper describes the isolation of Enterococcus host strains, for potential use as simple bacteriophage (phage)-based microbial source tracking (MST) tools. Presumptive Enterococcus host strains were isolated from cattle feces, raw municipal wastewater, agricultural runoff, and waters impacted by farms or wastewater treatment works (WWTW) in southern England, United Kingdom (UK). All enterococcal host strains (n = 390) were first screened for their ability to detect phage in samples of raw municipal wastewater and fecal material from cattle, pigs, and sheep. Host strains that detected phage (n = 147) were ranked according to both their specificity to a particular fecal source and also the number of phages (expressed as plaque-forming units, PFU) that they detected per milliliter of sample. Host strains that demonstrated host specificity and which detected phages at levels greater than 100 PFU/mL (n = 29) were further tested using additional fecal samples of human and nonhuman origin. The specificity and sensitivity of the enterococcal host strains were found to vary, ranging from 44 to 100% and from 17 to 83%, respectively. Most notably, seven strains exhibited 100% specificity to either cattle, human, or pig samples. Isolates exhibiting specificity to cattle were identified as belonging to the species Enterococcus casseliflavus , Enterococcus mundtii , or Enterococcus gallinarum , while human and pig isolates were members of either Enterococcus faecium or Enterococcus faecalis . The high specificity of phages infecting Enterococcus hosts and the simplicity and relatively low cost of the approach collectively indicate a strong potential for using this method as a tool in MST.

Assessing the effect of oxygen and microbial inhibitors to optimize ferricyanide-mediated BOD assay

Methods for short-term BOD analysis (BODst) based on ferricyanide mediator reduction have succeeded in overcoming some problems associated with the standard BOD test analysis (BOD5) such as long-term incubations (5 days), the need to dilute samples and low reproducibility. Here we present a bioassay where a Klebsiella pneumoniae environmental strain successfully reduces ferricyanide without de-aeration of the samples with linear BOD5 ranges between 30 and 500mgL−1 or 30 and 200mgL−1, using glucose-glutamic acid solution (GGA) or OECD standards respectively. We further propose a new assay termination solution that allows higher reproducibility and standardization of the cell-based assay, employing formaldehyde (22.7gL−1) or other compounds in order to stop ferricyanide reduction without affecting the amperometric detection and therefore replace the centrifugation step normally used to stop microbial-driven reactions in ferricyanide-mediated bioassays. These improvements led to an accurate determination of real municipal wastewater samples.

Synthesis of a molecularly imprinted polymer and its application for microextraction by packed sorbent for the determination of fluoroquinolone related compounds in water

Molecularly imprinted polymer (MIP) has been synthesized by precipitation polymerization using ciprofloxacin (CIP) as template for the analysis of fluoroquinolone antibiotics (FQs). This MIP material was packed as sorbent in a device for microextraction by packed sorbent (MEPS) combined with liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the analysis of selected FQs drugs including CIP, norfloxacin (NOR) and ofloxacin (OFLO) in municipal wastewater samples. In comparison to the new MIP-MEPS procedure, the target compounds were also determined by solid-phase extraction (MISPE) using the new molecular imprinted polymer material to validate the new MIP-MEPS method. The ability of the MIP for molecular recognition of CIP, NOR and OFLO was proved in presence of structurally different environmental relevant substances such as quinolones (Qs), flumequine (FLU), di(methyl)phthalate (DMP), technical 4-nonylphenol (NP), caffeine, Galaxolide ®, Tonalid ®, di(butyl)phthalate (DBP), Triclosan, bisphenol-A (BPA), carbamazepine, di(ethylhexyl)phthalate (DEHP), estradiol and octocrylene. The analysis of wastewater samples revealed the high selectivity of the synthesized polymer which was able to recognize and retain the target analytes by both extraction methods, the offline SPE with MIP material and the semi-automated MEPS packed with MIP material.

Effect of the addition of organic carbon sources on nitrous oxide emission in anaerobic-aerobic (low dissolved oxygen) sequencing batch reactors

The effect of additional organic carbon sources on the production of nitrous oxide (N2O) in anaerobic-aerobic (low dissolved oxygen) real wastewater treatment system was investigated. In this paper, three laboratory-scale sequencing batch reactors (SBRs) (SBR-1, SBR-2 and SBR-3) were operating under an anaerobic-aerobic (low dissolved oxygen, 0.15–0.45 mg·L−1) configuration. The SBRs were ‘long-term cultured’ respectively with a single municipal wastewater sample, sodium acetate, and a waste-activated sludge alkaline fermentation liquid as the additional carbon sources of real wastewater. Off-gas analysis showed that N2O was emitted into the atmosphere during the aerobic (low dissolved oxygen) period in the three SBRs, and the order of N2O emission rate was SBR-2>SBR-1>SBR-3. It was observed that the higher poly-β-hydroxyvalerate fraction of polyhydroxyalkanoates, the lower glycogen transformation and less nitrite accumulation was in SBR-3, while the opposite behavior was observed in SBR-2. Further research indicated that the interaction of the factors above potentially affected the N2O emission in the anaerobic-aerobic (low dissolved oxygen) system.

Photo-induced fluorescence of magnesium derivatives of tetracycline antibiotics in wastewater samples

An analytical strategy, for the determination of tetracyclines (TCs), based on a HPLC system coupled with a photo-reactor followed by post-column derivatization was developed. Higher fluorescence emission after coupling the resulting photo-fragments with magnesium ions was observed for the determination of minocycline (MC), epitetracycline (ETC), tetracycline (TC) and doxycycline (DC). The manifold included a HPLC system with a photo-reactor (PTFE tubing helically coiled around a low-pressure mercury lamp), a mixing T-piece and a fluorescence detector. The derivatization reagent was delivered at 0.5 mL min −1 by a pump. After HPLC separation using a gradient system with a mobile phase containing oxalic acid 0.02 M and acetonitrile, TCs were irradiated for 60 s, and the resulting photo-fragments were mixed with the post-column derivatization reagent, and the magnesium derivatives of TCs were detected by fluorimetry ( λ exc 386 nm, λ em 500 nm). The results obtained showed a significant increase of sensitivity due to photodegration of TCs, 45.4%, 37.6% and 25.3% for MC, TC and ETC respectively. For DC an increase of only 1.5% was observed. The developed method was successfully applied to TCs determination in hospital and municipal wastewater samples using solid phase extraction with Oasis HLB cartridges. The LOQs were 0.25, 0.15, 01 and 0.25 μg L −1 for TC, ETC, MC and DC, respectively. The recovery values oscillated between 107.1% and 92.4% for fortification of 2.5 μg L −1 of each antibiotic.

Analysis of hormone antagonists in clinical and municipal wastewater by isotopic dilution liquid chromatography tandem mass spectrometry

A comprehensive method was developed for the simultaneous trace analysis of ten hormone antagonist pharmaceuticals (raloxifene, exemestane, letrozole, anastrozole, mifepristone, finastride, tamoxifen, N-desmethyltamoxifen, clomiphene, and toremifene) in municipal sewage and hospital wastewater samples. The target compounds were firstly extracted using an Oasis HLB cartridge, followed by purification by an aminopropyl cartridge, and were then analyzed by liquid chromatography electrospray ionization tandem mass spectrometry in positive ion mode. The recoveries for the analytes based on internal standard calibration in different test matrices ranged from 67.6 to 118.6% (with the exception of mifepristone in clinical wastewater samples), with relative standard deviations less than 20%. The method quantification limits of the ten pharmaceuticals were in the range 0.10-2.0 ng/L. Excluding exemestane and N-desmethyltamoxifen, eight drugs were detected at 0.20-195.0 ng/L in hospital wastewater and municipal wastewater samples from Beijing.

Different Indices to Express Biodegradability in Organic Solid Wastes

Respiration indices are suggested in literature as the most suitable stability determination and are proposed as a biodegradability measure in this work. An improved dynamic respiration index methodology is described in this work. This methodology was applied to 58 samples of different types of waste including municipal solid wastes and wastewater sludge, both raw materials and samples collected in a mechanical-biological treatment plant at different stages of biodegradation. The information obtained allowed to establish a qualitative classification of wastes in three categories: highly biodegradable, moderately biodegradable, and wastes of low biodegradability. Results were analyzed in terms of long and short-term indices and index expression: dynamic respiration indices expressed as average oxygen uptake rate (mg O(2) g(-1) dry matter [DM] h(-1)) at 1 and 24 h of maximum activity (DRI(1h), DRI(24h)); and cumulative oxygen consumption in 24 h of maximum activity and 4 d (AT(24h), AT(4)). The statistical comparison of indices and wastes is also presented. Raw sludge presented the highest biodegradability followed by the organic fraction of municipal solid waste and anaerobically digested sludge. All indices correlated well but different correlations were found for the different wastes analyzed. The information in the dynamic respiration profile allows for the calculation of different indices that provide complementary information. The combined analysis of DRI(24h) and AT(4) is presented here as the best tool for biodegradable organic matter content characterization and process requirements estimation.

Isomer-Specific Determination of 4-Nonylphenols Using Comprehensive Two-Dimensional Gas Chromatography/Time-of-Flight Mass Spectrometry

Technical nonylphenol (tNP), used for industrial production of nonylphenol polyethoxylate surfactants, is a complex mixture of C(3-10)-phenols. The major components, 4-nonylphenols, are weak endocrine disruptors whose estrogenicities vary according to the structure of the branched nonyl group. Thus, accurate risk assessment requires isomer-specific determination of 4-NPs. Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC/ToFMS) was used to characterize tNP samples obtained from seven commercial suppliers. Under optimal chromatographic conditions, 153-204 alkylphenol peaks, 59-66 of which were identified as 4-NPs, were detected. The 4-NPs comprised approximately 86-94% of tNP, with 2-NPs and decylphenols making up approximately 2-9% and approximately 2-5%, respectively. The tNP products were analyzed for eight synthetic 4-NP isomers, and results were compared with published data based on GC/MS analysis. Significant differences were found among the products and between two samples from a single supplier. The enhanced resolution of GC x GC coupled with fast mass spectral data acquisition by ToFMS facilitated identification of all major 4-NP isomers and a number of previously unrecognized components. Analysis of tNP altered by the bacterium, Sphingobium xenophagum Bayram, revealed several persistent 4-NPs whose structures and estrogenicities are presently unknown. The potential of this technology for isomer-specific determination of 4-NP isomers in environmental matrices is demonstrated using samples of wastewater-contaminated groundwater and municipal wastewater.

Vortex-assisted liquid–liquid microextraction of octylphenol, nonylphenol and bisphenol-A

A new and fast equilibrium-based solvent microextraction technique termed vortex-assisted liquid-liquid microextraction (VALLME) has been developed and used for the trace analysis of octylphenol, nonylphenol and bisphenol-A in water and wastewater samples. According to VALLME, dispersion of microvolumes of a low density extractant organic solvent into the aqueous sample is achieved by using for the first time vortex mixing, a mild emulsification procedure. The fine droplets formed could extract target analytes towards equilibrium faster because of the shorter diffusion distance and larger specific surface area. Upon centrifugation the floating extractant acceptor phase restored its initial single microdrop shape and was used for high-performance liquid chromatographic analysis. Different experimental parameters were controlled and the optimum conditions found were: 50 microl of octanol as the extractant phase; 20 ml aqueous donor samples; a 2 min vortex extraction time with the vortex agitator set at a 2500 rpm rotational speed; centrifugation for 2 min at 3500 rpm; no ionic strength or pH adjustment. The calculated calibration curves gave high levels of linearity yielding correlation coefficients (r(2)) greater than 0.9935. The repeatability and reproducibility of the proposed method were found to be good and the limits of the detection were calculated in the low microg l(-1) level ranging between 0.01 and 0.07 microg l(-1). Matrix effects were determined by applying the proposed method to spiked tap, river water and treated municipal wastewater samples. The proposed method was finally applied to the determination of target pollutants in real wastewater effluent samples using the standard addition method.

Whole effluent risk estimation for a small recipient watercourse

Whole effluent toxicity is most often considered as a static parameter. However, toxicity might change as degradation processes, especially biodegradation goes by and intermediate products appear. These intermediates can even be more toxic than the original effluent was, posing higher risk to the ecosystem of the recipient water body. In our test series it was assessed how toxicity of a municipal wastewater sample changes during biodegradation taking into consideration different temperature regimes (10, 20 and 30 degrees C). Results proved our null hypothesis: after the high initial toxicity of the fresh effluent sample toxicity did show a further increase. Biodegradation resulted in toxicity reduction only after an approx. 2 week-period.

Clonal groups of high-level gentamicin-resistantEnterococcus faeciumisolated from municipal wastewater and clinical samples in Tehran, Iran

Clonality among high-level gentamicin-resistant Enterococcus faecium (HLGR-EF) isolates obtained from clinical and sewage treatment plants (STP) were investigated using PhePlate system (PhP), ribotyping and pulsed-field gel electrophoresis (PFGE). During 1 year study (September 2005-2006), a total of 106 HLGR-EF isolates were collected from clinical (n = 48) and STP (n = 58) samples in Tehran, Iran. Biochemical fingerprinting of these isolates using the PhP showed the presence of 21 PhP types (diversity index, Di = 0.97) among the clinical and 21 PhP types (Di = 0.91) among the STP isolates. Representative isolates of each PhP type (n = 42) were further characterized by the ribotyping method. Sixteen ribotypes were identified among the isolates with five types shared between the clinical and STP isolates. PFGE recognized 24 clonal types among these isolates with three pulsotypes shared between the clinical and STP isolates. Combination of the two techniques (PFGE and ribotyping) resulted in 24 (Di = 0.96) and 16 (Di = 0.93) types among the strains isolated from clinical and STP samples, respectively. We concluded that the combination of PhP typing, ribotyping and PFGE could be extremely discriminatory when examining HLGR-EF isolates. The emergence of highly diverse HLGR-EF population in Iran is of serious concern especially because of their multi-resistances.

Determination of widely used non-steroidal anti-inflammatory drugs in water samples by in situ derivatization, continuous hollow fiber liquid-phase microextraction and gas chromatography-flame ionization detector

The aim of this study was to develop an analytical procedure which allows the quantification of pharmaceuticals in water at the ng L −1 level. Hence, it is reported research on the application of a rapid, inexpensive and simple continuous hollow fiber liquid-phase micro extraction (CHF-LPME) for the pre-concentration and determination of non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (IBP), naproxen (NAP), and ketoprofen (KEP), in wastewater. In this method, a 2.50 cm end sealed piece of a polypropylene hollow fiber was immersed into the organic solvent, octanol, for 30 s. After solvent impregnation with the pores of the fiber, the excess amounts of solvent were removed from inside the fiber, and 4.0 μL of octanol, as the acceptor phase, was injected into the fiber carefully. The fiber was settled using a microsyringe into a 10.0 mL glass test tube, and 20.00 mL of the aqueous solution (the donor phase), was circulated by a pump around it. After analyte extraction for an optimized period of time (20 min), 2 μL of the organic solvent was withdrawn into the microsyringe and injected into the GC-FID for further analysis. Finally, based on the optimized analytical conditions, the method was linear in the range of 2.5–500 ng L −1. The limits of detection were 1–2 ng L −1. Repeatability of this method on an intra-day scale was 3.4–10.2% (RSD%). NSAIDs have been detected in several municipal wastewater samples, and the concentration range was 9.0–19.0 ng L −1.