Use of micropollutant indicator ratios to characterize wastewater treatment plant efficiency and to identify wastewater impact on groundwater.

Contamination by wastewater has been traditionally assessed by measuring faecal coliforms, such as E. coli and entereococci. However, using micropollutants to track wastewater input is gaining interest. In this study, we identified nine micropollutant indicators that could be used to characterize water quality and wastewater treatment efficiency in pond-based wastewater treatment plants (WWTPs) of varying configuration. Of 232 micropollutants tested, nine micropollutants were detected in treated wastewater at concentrations and frequencies suitable to be considered as indicators for treated wastewater. The nine indicators were then classified as stable (carbamazepine, sucralose, benzotriazole, 4+5-methylbenzotriazole), labile (atorvastatin, naproxen, galaxolide) or intermediate/uncertain (gemfibrozil, tris(chloropropyl)phosphate isomers) based on observed removals in the pond-based WWTPs and correlations between micropollutant and dissolved organic carbon removal. The utility of the selected indicators was evaluated by assessing the wastewater quality in different stages of wastewater treatment in three pond-based WWTPs, as well as selected groundwater bores near one WWTP, where treated wastewater was used to irrigate a nearby golf course. Ratios of labile to stable indicators provided insight into the treatment efficiency of different facultative and maturation ponds and highlighted the seasonal variability in treatment efficiency for some pond-based WWTPs. Additionally, indicator ratios of labile to stable indicators identified potential unintended release of untreated wastewater to groundwater, even with the presence of micropollutants in other groundwater bores related to approved reuse of treated wastewater.

Photodegradation of a mixture of five pharmaceuticals commonly found in wastewater: Experimental and computational analysis.

Photochemical transformation of pharmaceuticals plays an important role in their natural attenuation, especially in lagoon-based wastewater treatment plants and surface waters receiving substantial sunlight. In this study, the photodegradation of five important pharmaceuticals was studied in samples obtained from a wastewater treatment plant and surface water sources. Batch photodegradation studies for a mixture of pharmaceuticals (diclofenac, sulfamethoxazole, acetaminophen, carbamazepine and gemfibrozil) were carried out in a photochemical reactor. Multiple aliquots of samples removed from the reactor during the experiment were analyzed through high-performance liquid chromatography (HPLC) coupled to a photodiode array (PDA) detector. Intermediate products formed due to photodegradation were identified by ultra-high-performance liquid chromatography coupled with a time-of-flight mass spectrometry (UHPLC-MS/MS). Diclofenac and sulfamethoxazole were found to undergo direct photodegradation due to strong light absorption, whereas the indirect route of photosensitized degradation in the presence of dissolved organic matter (DOM) and model humic acid was significant for acetaminophen, carbamazepine, and gemfibrozil. The reactive radicals such as hydroxyl (OH•), singlet oxygen (1O2) and excited states of DOM (*DOM) were predominantly responsible for the indirect photodegradation of acetaminophen, gemfibrozil and carbamazepine, respectively. Computational analysis revealed that chlorine and carbon atoms belonging to the benzene ring of diclofenac were more reactive to radical attack. Sulfamethoxazole photodegradation occurred through oxidation of the NH2 group. Acetaminophen was more susceptible to electrophilic radical attack at the O-11, and N-7 positions and carbon atoms ortho to the phenolic oxygen and the amine group. The double bonds between C-7, C-8 and C-13 were the most reactive sites for carbamazepine that participated in the phototransformation pathway. Organic matter plays a critical role in the photodegradation of emerging contaminants. The coupling of DFT calculations with UHPLC-MS/MS analysis provided insights on key functional groups participating in the phototransformation pathway. Thus, both parent pharmaceuticals and the photodegradation intermediates should be considered during wastewater treatment.

Simultaneous analysis of gemfibrozil, morphine, and its two active metabolites in different mouse brain structures using solid-phase extraction with ultra-high performance liquid chromatography and tandem mass spectrometry with a deuterated internal standard.

A rapid and sensitive bioassay was established and validated to simultaneously determine gemfibrozil, morphine, morphine-3ß-glucuronide, and morphine-6ß-glucuronide in mouse cerebrum, epencephalon, and hippocampus based on ultra-high performance liquid chromatography and tandem mass spectrometry. The deuterated internal standard, M6G-d3, was mixed with the prepared samples at 10 ng/mL as the final concentration. The samples were transferred into the C18 solid-phase extraction columns with gradient elution for solid-phase extraction. The mobile phase consisted of methanol and 0.05% formic acid (pH 3.2). Multiple reaction monitoring has been applied to analyze gemfibrozil (m/z 249.0 → 121.0) in anion mode, and M6G-d3 (m/z 465.1 → 289.1), morphine (m/z 286.0 → 200.9), and M3G and M6G (m/z 462.1 → 286.1) in the positive ion mode. The method has a linear calibration range from 0.05 to 10 ng for gemfibrozil, morphine, and M3G and M6G with correlation coefficients >0.993. The lower limit of quantitation for all four analytes was 0.05 ng/mL, relative standard deviation of intra- and interday precision was less than 10.5%, and the relative error of accuracy was from -8.2 to 8.3% at low, medium, and high concentrations for all the analytes. In conclusion, gemfibrozil can influence the morphine antinociception after coronary heart disease induced chronic angina by the change in one of morphine metabolites', M3G, distribution in mouse brain.

Analytical and biological characterization of halogenated gemfibrozil produced through chlorination of wastewater.

The cholesterol-lowering pharmaceutical gemfibrozil is a relevant environmental contaminant because of its frequency of detection in U.S. wastewaters at concentrations which have been shown to disrupt endocrine function in aquatic species. The treatment of gemfibrozil solutions with sodium hypochlorite yielded a 4'-chlorinated gemfibrozil analog (chlorogemfibrozil). In the presence of bromide ion, as is often encountered in municipal wastewater, hypobromous acid generated through a halogen exchange reaction produced an additional 4'-brominated gemfibrozil product (bromogemfibrozil). Standards of chloro- and bromogemfibrozil were synthesized, isolated and characterized using mass spectrometry and NMR spectroscopy. Mass spectrometry was used to follow the in situ halogenation reaction of gemfibrozil in deionized water and wastewater matrices, and to measure levels of gemfibrozil (254 ± 20 ng/L), chlorogemfibrozil (166 ± 121 ng/L), and bromogemfibrozil (50 ± 11 ng/L) in advanced primary wastewater treatment effluent treated by chlorination. Chlorogemfibrozil demonstrated a significant (p < 0.05) reduction in the levels of 11-ketotestosterone at 55.1 µg/L and bromogemfibrozil demonstrated a significant (p < 0.05) reduction in the levels of testosterone at 58.8 µg/L in vivo in Japanese medaka in a 21 day exposure. These results indicated that aqueous exposure to halogenated degradates of gemfibrozil enhanced the antiandrogenicity of the parent compound in a model fish species, demonstrating that chlorination may increase the toxicity of pharmaceutically active compounds in surface water.

Distribution and temporal evolution of pharmaceutically active compounds alongside sewage sludge treatment. Risk assessment of sludge application onto soils.

In this work, the distribution and the ecotoxicological risk of sixteen pharmaceutically active compounds belonging to seven different therapeutic groups (five anti-inflammatory drugs, two antibiotics, an anti-epileptic drug, a ß-blocker, a nervous stimulant, four estrogens and two lipid regulators) have been studied in sewage sludge from wastewater treatment plants. Only three of the sixteen pharmaceutical compounds were never detected in sludge while eleven of the studied pharmaceuticals were still detected in compost. Mean concentration levels of the pharmaceutically active compounds ranged between 24.9 and 4105 µg/kg dm, 14.5-944 µg/kg dm, 3.29-636 µg/kg dm and 9.19-974 µg/kg dm in primary, secondary, digested sludge and compost, respectively. An increase in the concentration levels of most of the pharmaceuticals was observed from summer to winter (mean values in primary and secondary sludge were 304 and 85.1 µg/kg dm in summer and 435 and 175 µg/kg dm in winter, respectively) probably due to an increase of their consumption during the coldest season and a reduction of the microbial activity under colder temperatures. The highest ecotoxicological risk, in digested sludge and compost, was due to the estrogenic compound 17ß-estradiol. The ecotoxicological risk significantly decreased after the application of digested sludge or compost to the soils (risk quotient values ranged between 0.04 and 252 in digested sludge and 0.002-37.8 in compost and decreased to 8·10(-4)-1.92 in digested sludge-amended soil and 1·10(-4)-0.23 in compost-amended soil).

Pharmaceuticals, natural and synthetic hormones and phenols in sediments from an eutrophic estuary, Jurujuba Sound, Guanabara Bay, Brazil.

A screening for microcontaminants performed by gas chromatography detected several microcontaminants in 12 sediment samples from the eutrophic estuary Guanabara Bay (GB) in southeastern Brazil. Bisphenol A (BPA) ranged from 1.4 to 20.3 ng g-1, 4-octylphenol, from

Methods of chromatographic determination of medicines decreasing the level of cholesterol.

With reference to common application of HPLC to routine analytical tests on medicinal products decreasing the level of cholesterol, including three compounds from this group--fenofibrate, bezafibrate and etofibrate, we developed a new method for determining two other compounds--ciprofibrate and gemfibrozil. The developed HPLC method may be used for identification and qualitative determination of selected compounds--derivatives of aryloxyalkylcarboxylic acids as well as it may be used for simultaneous separation and determination of all compounds from the group of fibrates using one column and the same methodology. The results and statistical data indicate good sensitivity and precision. The RSD value presented is equivalent to the newly developed method of determinination of ciprofibrate and gemfibrozil in the substances and medicinal products--capsules and coated tablets.

Automated zone-sampling dilution by coupling sequential injection analysis to high-throughput HPLC for the direct determination of gemfibrozil.

A novel automated analytical scheme for the rapid determination of gemfibrozil in drug dissolution samples is reported. The procedure is based on direct coupling of a low pressure continuous flow technique such as sequential injection analysis (SI) to HPLC. SI performs automated dilution of the samples based on zone sampling and fills on-line the loop of the high pressure injection valve. Rapid separation of the analyte from the samples' matrix can be achieved in less than 1.0 min, by using a short RP monolithic column (25x4.6 mm id) at a flow rate of 2 mL/min. The SI and HPLC parts of the setup operate independently: during HPLC separation the next sample is treated by SI. This way a maximum throughput of 60 samples per hour is achieved allowing the complete analysis of a batch of six dissolution samples within 12-18 min based on the replicates. The proposed method was validated in terms of linearity, LOD and LOQ, precision, selectivity and accuracy. Its applicability was tested during quality control of four validation batches of a gemfibrozil-containing formulation. The results were in good agreement with the HPLC method proposed by the US Pharmacopeia.

High-performance liquid chromatography method for determination of carnosic acid in rat plasma and its application to pharmacokinetic study.

A sensitive and reproducible high-performance liquid chromatography method with ultraviolet detection (UV) was developed for the determination of carnosic acid (CA) in rat plasma. After simple acidification and liquid-liquid extraction of plasma samples using gemfibrozil as an internal standard, the supernatant was evaporated to dryness under a gentle stream of nitrogen. The residue was reconstituted in 200 microL before being injected into the chromatographic system. The analysis was performed on a C(18) column protected by an ODS guard column using acetonitrile-0.1% phosphoric acid (55:45, v/v) as mobile phase, and the wavelength of the UV detector was set at 210 nm. The calibration curve was linear over the range of 0.265-265.0 microg/mL with a correlation coefficient of 0.9997. The recovery for plasma samples of 0.530, 13.25, 132.5 and 265.0 microg/mL was 72.2, 87.9, 90.4 and 94.7%, respectively. The intra-day and inter-day relative standard deviations for the measurements of quality control samples were less than 3.1%. The stability of the plasma samples was also validated. This method was successfully used to study the pharmacokinetics and bioavailability of CA in rats.

Occurrence and distribution of pharmaceutical compounds in the Danshuei River Estuary and the Northern Taiwan Strait.

Ten pharmaceutically active compounds (PhACs) were determined in northern Taiwan estuarine waters and Taiwan Strait (TS) seawater. The ecological risk of these PhACs was assessed using risk quotient (RQ), which is the ratio of the measured maximum concentration to the predicted no-effect concentration. Six PhACs were detected within the estuarine waters. Caffeine concentration (130-718 ng l-1) was the highest among the analyzed PhACs. The distribution of PhACs in the Danshuei River Estuary generally exhibited addition behavior, except that caffeine showed conservative behavior. Carbamazepine, gemfibrozil, caffeine, and ketoprofen were detected in TS seawaters. Their concentrations follow the sequence: gemfibrozil > ketoprofen > caffeine > carbamazepine. The caffeine concentrations in TS seawaters were 2-3 orders of magnitude lower than those in Danshuei estuarine waters. With few exceptions for caffeine, erythromycin, and sulfadiazine posing low risk in some estuarine waters, most of the RQ values were <0.01, suggesting no adverse effects on aquatic organisms.

Advances in stir bar sorptive extraction for the determination of acidic pharmaceuticals in environmental water matrices Comparison between polyurethane and polydimethylsiloxane polymeric phases.

Stir bar sorptive extraction with polyurethane (PU) and polydimethylsiloxane (PDMS) polymeric phases followed by high-performance liquid chromatography with diode array detection [SBSE(PU or PDMS)/HPLC-DAD] was studied for the determination of six acidic pharmaceuticals [o-acetylsalicylic acid (ACA), ibuprofen (IBU), diclofenac sodium (DIC), naproxen (NAP), mefenamic acid (MEF) and gemfibrozil (GEM)], selected as non-steroidal acidic anti-inflammatory drugs and lipid regulators model compounds in environmental water matrices. The main parameters affecting the efficiency of the proposed methodology are fully discussed. Assays performed on 25 mL of water samples spiked at the 10 microg L(-1) level under optimized experimental conditions, yielded recoveries ranging from 45.3+/-9.0% (ACA) to 90.6+/-7.2% (IBU) by SBSE(PU) and 9.8+/-1.6% (NAP) to 73.4+/-5.0% (GEM) by SBSE(PDMS), where the former polymeric phase presented a better affinity to extract these target analytes from water matrices at the trace level. The methodology showed also excellent linear dynamic ranges for the six acidic pharmaceuticals studied, with correlation coefficients higher than 0.9976, limits of detection and quantification between 0.40-1.7 microg L(-1) and 1.5-5.8 microg L(-1), respectively, and suitable precision (RSD <15%). Moreover, the developed methodology was applied for the determination of these target analytes in several environmental matrices, including river, sea and wastewater samples, having achieved good performance and moderate matrix effects. In short, the PU foams demonstrated to be an excellent alternative for the enrichment of the more polar metabolites from water matrices by SBSE, overcoming the limitations of the conventional PDMS phase.

Analysis of the complexation of gemfibrozil with gamma- and hydroxypropyl-gamma-cyclodextrins.

The interactions of gemfibrozil with gamma- and HP-gamma-cyclodextrin (CD) have been studied in aqueous solution by fluorescence and NMR spectroscopy and by solubility measurements and in the solid state by X-ray diffraction, thermal analysis and FTIR spectroscopy. The influence of the technique employed in the analysis of complexation is discussed. The fluorescence of gemfibrozil increased in the presence of gamma- and hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD), especially with the later, because the inclusion of the aromatic ring in the cavity, evidenced by 1H NMR, has a protective effect on the excited state of the drug. The fluorescence enhancement allowed the determination of the binding constants at pH 2.8. Complexation was a both entropy and enthalpy driven process. The solubility diagrams obtained with gamma-CD and HP-gamma-CD were B(s) and A(L) type, respectively. The apparent stability constants calculated from the solubility data at 25 degrees C were compared with those obtained from the fluorescence assays. It was found that drug solubilization with gamma-CD involves other contributions together with the inclusion phenomena. Solid complexes of gemfibrozil with gamma-CD (and not with HP-gamma-CD) have been obtained by kneading, coevaporation and coprecipitation methods. The solid complexes crystallised in the channel structure, in a process involving the carboxyl and aryl-ether groups.

Unveiling the important roles of coexisting contaminants on photochemical transformations of pharmaceuticals: Fibrate drugs as a case study.

Pharmaceuticals are a group of ubiquitous emerging pollutants, many of which have been shown to undergo efficient photolysis in the environment. Photochemically produced reactive intermediates (PPRIs) sensitized by the pharmaceuticals in sunlit natural waters may induce photodegradation of coexisting compounds. In this study, the roles of coexisting contaminants on the phototransformation of pharmaceuticals were unveiled with the fibrate drugs gemfibrozil (GMF), fenofibrate (FNF), and fenofibric acid (FNFA) as model compounds. GMF undergoes initial concentration dependent photodegradation due to the involvement of singlet oxygen (1O2) initiated self-sensitized photolysis, and undergoes pH dependent photodegradation due to dissociation and hydroxyl radical (OH) generation. The decarboxylated intermediates of GMF and coexisting FNFA significantly accelerated the photodegradation of GMF. The promotional effects of the decarboxylated intermediates are attributed to generation of PPRIs, e.g. 1O2, superoxide (O2-), that subsequently react with GMF. Besides, FNFA can also promote the photodegradation of GMF through the electron transfer reaction from ground state GMF to excited state FNFA, leading to the formation of decarboxylated intermediates. The formed intermediates can subsequently also facilitate GMF photodegradation. The results presented here provided valuable novel insights into the effects of coexisting contaminants on the photodegradation of pharmaceuticals in polluted waters.

Effects of gemfibrozil on the growth, reproduction, and energy stores of Daphnia magna in the presence of varying food concentrations.

Gemfibrozil, a common lipid regulator, enters aquatic environments through treated municipal wastewater effluent that fails to remove it completely from effluent streams. When exposed to gemfibrozil concentrations of 50, 500, 5,000, and 50,000 ng L-1, Daphnia magna showed increased lipid reserves by 14-21% (significant at 500 ng L-1), increased length by 9-13% (significant at 50 ng L-1), increased mass by 6-13% (significant at 50 ng L-1) and increased neonate production by 57-74% (significant at 50 ng L-1). Gemfibrozil-exposed Daphnia held under conditions where food availability was low, grew and reproduced as well as those in the control. Taken together, these results suggest that gemfibrozil exposure within environmentally relevant concentration ranges is not toxic to Daphnia magna but has the potential to be beneficial to the species under these conditions.

Modelling the photochemical attenuation pathways of the fibrate drug gemfibrozil in surface waters.

Gemfibrozil (GFZ) is a relatively persistent pollutant in surface-water environments and it is rather recalcitrant to biological degradation. The GFZ photochemical lifetimes are relatively short in shallow waters with low levels of dissolved organic carbon (DOC), but they can reach the month-year range in deep and high-DOC waters. The main reason is that GFZ undergoes negligible reaction with singlet oxygen or degradation sensitised by the triplet states of chromophoric dissolved organic matter, which are the usually prevalent photochemical pathways in deep and high-DOC sunlit waters. Nitrate and nitrite scarcely affect the overall GFZ lifetimes, but they can shift photodegradation from direct photolysis to the OH process. These two pathways are the main GFZ phototransformation routes, with the direct photolysis prevailing in shallow environments during summer. Under these conditions the GFZ photochemical lifetimes are also shorter and the environmental significance of photodegradation correspondingly higher. The direct photolysis of GFZ under UVB irradiation yielded several transformation intermediates deriving from oxidation or cleavage of the aliphatic lateral chain. A quinone derivative (2,5-dimethyl-1,4-benzoquinone), a likely oxidation product of the transformation intermediate 2,5-dimethylphenol, is expected to be the most acutely and chronically toxic compound arising from GFZ direct photolysis. Interestingly, literature evidence suggests that the same toxic intermediate would be formed upon OH reaction.

Occurrence of fibrates and their metabolites in source and drinking water in Shanghai and Zhejiang, China.

Fibrates, which are widely used lipidaemic-modulating drugs, are emerging environmental pollutants. However, fibrate concentrations in the environment have not been thoroughly surveyed. Here, we determined concentrations of the most commonly used fibrates and their metabolites in source water and drinking water samples from ten drinking water treatment plants in Shanghai and Zhejiang, China, using solid-phase extraction and liquid chromatography-tandem mass spectrometry. All the target compounds were detected in at least some of the source water samples, at concentrations ranging from 0.04 ng/L (fenofibrate) to 1.53 ng/L (gemfibrozil). All the compounds except fenofibrate were also detected in at least some of the drinking water samples, at recoveries ranging from 35.5% to 91.7%, suggesting that these compounds are poorly removed by typical drinking water treatment processes. In a peroxisome proliferator-activated receptor α agonistic activity assay, the target compounds showed no significant activity at nanogram per litre concentrations; therefore, our results suggest that the fibrate concentrations in drinking water in Shanghai and Zhejiang, China do not significantly affect human health. However, because of the increasing westernization of the Chinese diet, fibrate use may increase, and thus monitoring fibrate concentrations in aquatic environments and drinking water in China will become increasingly important.

Separation of fibrate-type antihyperlipidemic drugs by capillary electrophoresis and their quantitation in pharmaceuticals.

Six antihyperlipidemic agents-bezafibrate, ciprofibrate, clofibrate, clofibric acid, fenofibrate and gemfibrozil were separated by means of capillary electrophoresis, using unmodified fused silica tubing of 75 microm internal diameter and 87 cm length (65 cm to the UV detector at 227 nm). Migration time and selectivity were examined in differing pH of separation buffer, varying separation voltage and differing temperature. Optimal separation was achieved using 1/15 M phosphate buffer pH 10, 240 V/cm at 25 degrees C. The optimal separation conditions were then used to elaborate the method of quantitation of bezafibrate, ciprofibrate and gemfibrozil in Bezamidin, Lipanor and Gemfibral pharmaceuticals. The clofibric acid was used as internal standard. The calibration curve was constructed from 0.2 to 0.8 mg/ml of each compound and 0.5 mg/ml of internal standard. The calibration data were proved to be linear by Mandel and Lack-of-fit tests. Statistical evaluation of results proved proper recovery of elaborated method (102.42, 97.32 and 101.51%, respectively) and good repeatability (9.51, 5.52 and 11.15%, respectively). The linearity of recovery was also tested by analyzing increasing amount of the samples. Three fortified samples of each drug were also analyzed to perform additional accuracy validation.

ß-Cyclodextrin anchoring onto pericarpium granati-derived magnetic mesoporous carbon for selective capture of lopid in human serum and pharmaceutical wastewater samples.

Functionalized magnetic carbonaceous nanomaterials, which are important materials with many practical and research applications in biomedical, pharmaceutical and biological fields, have recently attracted much attention. In this study, a magnetic mesoporous carbon coated with ß-cyclodextrin (MMC@ß-CD) was synthesized for the first time from natural pericarpium granati (PG). The as-obtained MMC@ß-CD has high surface areas (203 m(2)g(-1)), large pore volumes (0.16 cm(3)g(-1)), relatively broad mesoporous sizes (6.8 nm) and a high saturation magnetization of 26.2 emu g(-1), which is sufficient for magnetic separation by an external magnetic field. The MMC@ß-CD was used as an innovative adsorbent for magnetic solid-phase extraction of lopid via host-guest interaction prior to spectrofluorometric analysis. The proposed method was successfully applied to analyze lopid in human serum and pharmaceutical wastewater samples with recoveries in the range of 85.0-103.5% for the spiked samples. Overall, this work not only provides an inexpensive and eco-friendly method to fabricate MMC@ß-CD (or MMC) from PG, but also develops a highly selective approach for capture of lopid in biological samples and environmental substances.

Determination of fenofibrate and gemfibrozil in pharmaceuticals by densitometric and videodensitometric thin-layer chromatography.

New thin-layer chromatography (TLC) methods with densitometric and videoscanning detection were elaborated for the quantitative determination of fenofibrate in Fenoratio capsules and gemfibrozil in Gemfibral tablets. Analysis was performed on high-performance TLC diol F254 plates using hexane-tetrahydrofuran (8 + 2, v/v) mobile phase in horizontal DS chambers using the sandwich technique. The active substances were extracted from tablets with methanol. Densitometric assay was performed at 227 nm and videoscanning quantitation at 254 nm. Calibration plots were constructed in range 5-30 microg/spot (20 microL of solutions in different concentrations) for both of the drugs. The calibration data were tested against 3 regression models, and the optimum model was selected (quadratic for videoscanning and nonlinear y = ax(m) + b for the densitometric method, R2 > 0.997 in all cases). Linearity of the methods was tested by spotting different amounts of extracted solution (15-30 mg/spot). The recovery function was sufficiently linear in all cases, with an insignificant intercept and a slope very close to 1. Accuracy was tested by quantitating 3 fortified samples (50,100, and 150% of theoretical), and the results were homogeneous with no significant differences. The recovery in the densitometric assay was 101.42% (total relative standard deviation 10.76%) for fenofibrate and 100.47% (9.7%) for gemfibrozil. Videodensitometry resulted in recoveries of 102.73% (12.59%) and 98.79% (8.56%), respectively. The F-Snedecor test and Student's t-test for 2 means showed no significant differences between the precision and accuracy of both methods.

Magnetic solid phase extraction of gemfibrozil from human serum and pharmaceutical wastewater samples utilizing a ß-cyclodextrin grafted graphene oxide-magnetite nano-hybrid.

A magnetic solid phase extraction method based on ß-cyclodextrin (ß-CD) grafted graphene oxide (GO)/magnetite (Fe3O4) nano-hybrid as an innovative adsorbent was developed for the separation and pre-concentration of gemfibrozil prior to its determination by spectrofluorometry. The as-prepared ß-CD/GO/Fe3O4 nano-hybrid possesses the magnetism property of Fe3O4 nano-particles that makes it easily manipulated by an external magnetic field. On the other hand, the surface modification of GO by ß-CD leads to selective separation of the target analyte from sample matrices. The structure and morphology of the synthesized adsorbent were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The experimental factors affecting the extraction/pre-concentration and determination of the analyte were investigated and optimized. Under the optimized experimental conditions, the calibration graph was linear in the range between 10 and 5000 pg mL(-1) with a correlation coefficient of 0.9989. The limit of detection and enrichment factor for gemfibrozil were 3 pg mL(-1) and 100, respectively. The maximum sorption capacity of the adsorbent for gemfibrozil was 49.8 mg g(-1). The method was successfully applied to monitoring gemfibrozil in human serum and pharmaceutical wastewaters samples with recoveries in the range of 96.0-104.0% for the spiked samples.