Application of solid-phase microextraction for in vivo laboratory and field sampling of pharmaceuticals in fish

Application of non-lethal bioSPME-LC-MS/MS for the detection of human pharmaceuticals in soft corals: A survey at the North Nilandhe atoll (Maldives)

At present the information regarding the occurrence of human pharmaceuticals (PhaCs) in coral reefs and their potential impacts on the associated fauna is limited. To optimize the collection of data in these delicate environments, we employed a solid-phase microextraction (bioSPME) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) procedure that enabled in vivo determinations in soft corals. Specifically, we researched the antibiotics Ofloxacin Sulfamethoxazole and Clarithromycin, the anti-inflammatory Diclofenac Propyphenazone Ketoprofen and Amisulpride, the neuroactive compounds Gabapentin-lactam, the beta-blocker Metoprolol and the antiepileptic Carbamazepine. Reproducibility was between 2.1% and 9.9% and method detection limits LODs) were between 0.2 and 1.6 ng/g and LOQs between 0.8 and 5.4 mg/g. The method was then applied to establish a baseline for the occurrence of these compounds in the Maldivian archipelago. Colonies of Sarcophyton sp. and Sinularia sp. were sampled along an inner-outer reef transect. Five of the ten targeted PhaCs were identified, and 40% of the surveyed coral colonies showed the occurrence of at least one of the selected compounds. The highest concentrations were found inside the atoll rim. Oxoflacin (9.5 ± 3.9 ng/g) and Ketoprofen (4.5 ± 2.3 ng/g) were the compounds with the highest average concentrations. Outside the atoll rim, only one sample showed contamination levels above the detection limit. No significant differences were highlighted among the two surveyed soft coral species, both in terms of average concentrations and bioconcentration factors (BCFs).

Imprinted covalent organic frameworks solid-phase microextraction fiber for in vivo monitoring of acidic per- and polyfluoroalkyl substances in live aloe

Per- and polyfluoroalkyl substances (PFASs) can lead to risks associated with animal and human health through the transfer along food chains. It is confirmed that PFASs can be transported to each part of plants after taken up by the roots. To better elucidate the underlying mechanisms for such exposure, it is highly valuable to develop analytical capabilities for in vivo monitoring of PFASs in live plants. In this work, a novel imprinted covalent organic frameworks (CMIP) solid-phase microextraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry was developed with low limits of detection for six acidic PFASs (0.1-0.3 ng g-1) and used for in vivo monitoring in live aloe. The CMIP coating shows good precision (RSD of intra and inter ≤9.6 % and 10.2 %, respectively) and possesses much higher extraction efficiency than the commercial coatings. After cultivating aloe in soil spiked PFASs, the in vivo assays gave a wealth of information, including steady-state concentrations, translocation factors, elimination rate constants, and half-life of PFASs. The in vivo tracing method for live plants can provide much needed and unique information to evaluate the risk of PFASs, which are very important for the safety of agriculture production.

Insights into the degradation of diphenhydramine - An emerging SARS-CoV-2 medicine by UV/Sulfite

As Diphenhydramine (DPH) has been considered as a drug to treat SARS-CoV-2, the degradation of DPH from water was investigated and evaluated in this study by adopting an advanced oxidation/advanced reduction process – the UV/sulfite process. The UV/sulfite system was able to eliminate DPH within 6 mins under UV_254nm and 1.0 mM sulfite. It was observed that the presence of NO3-, NO2-, Cl-, HCO3-, and SO42- anions in water can affect the performance of UV/Sulfite degradation system. The mechanism of UV/sulfite/anions was evaluated which the presence of NO3- in UV/sulfite process has revealed faster initial decay rate but lower final DPH removal. It was observed that the UV/Sulfite process was extremely sensitive to pH as the dissociation of ion species varied among pH. The reaction became sluggish in acidic solution due to the dissociation of less reactive species such as HSO₃^-. In alkaline solution, SO₃^2- was the dominant species, producing powerful SO3∙- and eaq- when activated by UV at 254 nm. By conducting LC/MS analysis, the degradation pathway was proposed and can be summarized into four main pathways: hydroxylation, side chain cleavage, losing aromatic ring or ring opening. Scavenging tests were also carried out and validated the presence of various radicals contributing to the reaction, including eaq-, H^˙, OH^˙, SO₃^˙-, O₂^•- and SO₄^˙-.

Advanced Solid-Phase Microextraction Techniques and Related Automation: A Review of Commercially Available Technologies

The solid-phase microextraction (SPME), invented by Pawliszyn in 1989, today has a renewed and growing use and interest in the scientific community with fourteen techniques currently available on the market. The miniaturization of traditional sample preparation devices fulfills the new request of an environmental friendly analytical chemistry. The recent upswing of these solid-phase microextraction technologies has brought new availability and range of robotic automation. The microextraction solutions propose today on the market can cover a wide variety of analytical fields and applications. This review reports on the state-of-the-art innovative solid-phase microextraction techniques, especially those used for chromatographic separation and mass-spectrometric detection, given the recent improvements in availability and range of automation techniques. The progressively implemented solid-phase microextraction techniques and related automated commercially available devices are classified and described to offer a valuable tool to summarize their potential combinations to face all the laboratories requirements in terms of analytical applications, robustness, sensitivity, and throughput.

Biological uptake, depuration and biochemical effects of diclofenac and carbamazepine in Carassius carassius

The uptake and depuration kinetics of diclofenac and carbamazepine alone at an environmentally relevant nominal concentration of 2 μg/L and in combination at a concentration ratio of 1:1 with total concentration of 4 μg/L were evaluated in Carassius carassius after 7 d uptake and depuration. Also, the biochemical effects of both drugs alone at nominal concentrations of 2 and 10 μg/L as well as in combination with total concentrations of 4 and 20 μg/L were investigated in Carassius carassius after 7 d exposure followed by 10 d recovery. In the single treatments, steady-state BCFs measured after the 7 d exposure were 73.05, 49.71, 38.01 and 24.93 L/kg for diclofenac and 9.25, 8.99, 5.29 and 4.11 L/kg for carbamazepine in the liver, brain, gill and muscle of Carassius carassius, respectively. Comparatively lower BCFs were measured in the tissues of Carassius carassius for both drugs in the combined treatments. Acetylcholinesterase activity in the brain was significantly induced by diclofenac while carbamazepine and the mixtures significantly inhibited it during all the exposure days as well as after the 10 d recovery in all treatments. This indicates that Carassius carassius could not recover from the neurotoxic effects caused by carbamazepine unlike the inductive effect caused by diclofenac which was recoverable after 10 days. A significant increase in the activities of 7-ethoxyresorufin O-deethylase and glutathione s-transferase for individual and mixed pharmaceuticals suggest that metabolism and detoxification of both drugs took place in the liver of Carassius carassius. Also, a significant increase in the activities of superoxide dismutase, catalase, glutathione reductase and malondialdehyde contents in the individual and mixture treatments mean that the antioxidant defence system of Carassius carassius was triggered to fight against oxidative stress but lipid peroxidation still occurred. However, Carassius carassius recovered from all these increases (superoxide dismutase, catalase, glutathione reductase and malondialdehyde) after the 10 d recovery, suggesting that oxidative damage is reversible. Our results indicate that both drugs at environmentally relevant concentrations might cause adverse effects in Carassius carassius and other fish species.

Paradigm Shift in the Arena of Sample Preparation and Bioanalytical Approaches Involving Liquid Chromatography Mass Spectroscopic Technique

Sample preparation is a highly important and integral part of bioanalysis for cleaning up the complex biological matrices and thereby minimizing matrix effect. Matrix effect can jeopardize the precise quantification and adversely affect the reliability of liquid chromatography-mass spectrometry-based analytical results by alteration of analyte ionization. Matrix components result in suppression or enhancement of the intensity of analyte response. In spite of the high specificity and selectivity of tandem mass spectrometry, a relatively higher concentration of coeluted matrix elements present in biofluids may alter the efficiency of quantification of a bioanalytical method. Numerous literature reports different types of sample preparation techniques employed in bioanalysis. In this review, the strategies for selection of the appropriate sample clean-up technique in bioanalysis are discussed extensively. A paradigm shift in the arena of sample preparation and bioanalytical approaches involving the liquid chromatography-mass spectroscopic technique has been scrutinized. Current trends and possible future advancements in the field of biological sample extraction methods, including instrumental techniques are analyzed in detail.

A Novel Water-Swelling Sampling Probe for in Vivo Detection of Neonicotinoids in Plants

Ecotoxicological risks of neonicotinoid insecticides are raising significant concerns, including their potential role in bee population declines. Neonicotinoids are water-soluble, systemic insecticides, and exposure of nontarget organisms such as pollinators occurs mainly through residues in nectar and pollens of flowering plants. To better elucidate the underlying mechanisms for such nontarget exposure, it is highly valuable to develop analytical capabilities for in vivo monitoring of neonicotinoids in live plants. In this study, we developed a novel biomimetic water-swelling solid-phase microextraction (SPME) probe, with limits of detection for neonicotinoids as low as 0.03 ng mL^-1, and applied it for in vivo detection of seven neonicotinoids in plant sap. The preparation of this fiber was simple and free of stringent or complex physical-chemical reactions. Equilibrium in neonicotinoid accumulation on the fiber was reached in <10 min, allowing for near instantaneous sampling. The water-swelling fiber displayed much greater sampling capacity than the commercially available polydimethylsiloxane and polyacrylate fibers, good reproducibility (RSD of inter- and intrafiber <8.9% and 7.8%, respectively), and antibiofouling property (no loss in performance after 20 use cycles). After treating lettuce (Lactuca sativa L.) by foliar spray and soybean (Glycine max M.) by seed soaking, the in vivo assays provided a wealth of information, including changes in levels and distribution of neonicotinoids over time in the same plants. Kinetics and distribution patterns suggested that after treatment at the same level, neonicotinoids differed significantly in their levels in the sap. The in vivo sampling and monitoring of neonicotinoids in live plants may provide unique and much needed information in achieving breakthrough understanding of the connection between neonicotinoid use and pollinator exposure.

Development and validation of a fully automated solid phase microextraction high throughput method for quantitative analysis of multiresidue veterinary drugs in chicken tissue

This paper presents the development and validation of a fully automated, high-throughput multiclass, multiresidue method for quantitative analysis of 77 veterinary drugs in chicken muscle via direct immersion solid phase microextraction (DI-SPME) and ultra-high pressure liquid chromatography-electrospray ionization - tandem mass spectrometry (UHPLC-ESI-MS/MS). The selected drugs represent more than 12 different classes of drugs characterized by varying physical and chemical properties. A Hydrophilic-lipophilic balance (HLB)/polyacrylonitrile (PAN) extraction phase, prepared using HLB particles synthesized in-house, yielded the best extraction/desorption performance among four different SPME extraction phases evaluated in the current work. The developed SPME method was optimized in terms of SPME coating and geometry, desorption solvent, extraction and rinsing conditions, and extraction and desorption times. Multivariate analysis was performed to determine the optimal desorption solvent for the proposed application. The developed method was validated according to the Food and Drug Administration (FDA) guidelines, taking into account Canadian maximum residue limits (MRLs) and US maximum tolerance levels for veterinary drugs in meat. Method accuracy ranged from 80 to 120% for at least 73 compounds, with relative standard deviation of 1-15%. Inter-day precision ranged from 4 to 15% for 70 compounds. Determination coefficients values were higher than 0.991 for all compounds under study with no significant lack of fit (p > 0.05) at the 5% level. In terms of limits of quantitation, the method was able to meet both Canadian and US regulatory levels for all compounds under study.

Implementing solid phase microextraction (SPME) as a tool to detect volatile compounds produced by giant pandas in the environment

Chemical cues are thought to play an important role in mate identification in the solitary giant panda (Ailuropoda melanoleuca). The goal of this study was to detect and identify volatile compounds present in the enclosure air of captive giant pandas. We hypothesized that a subset of compounds produced from breeding animals would be detected in environmental samples because highly volatile chemicals are likely to facilitate mate detection. Samples were collected from the enclosures of 8 giant pandas (n = 4 male, n = 4 female) during the Mar-June breeding season and the Aug-Jan non-breeding period from 2012-2015. Volatile compounds were captured by securing a solid phase micro extraction fiber approximately 3 meters above the ground within a panda enclosure for 6-12 hours. Compounds adsorbed onto the SPME fibers were analyzed by gas chromatography mass spectrometry. Thirty-three compounds were detected in at least 10% of all samples within individual and season and across all subjects within each season. Aromatic compounds made up 27.3% of the enclosure volatile profile, while 21.2% was made of cyclic aliphatic compounds and 51.5% of the enclosure profile was comprised of acyclic aliphatic compounds. Three compounds were likely to be present in male enclosures regardless of season, while Undecane, 4-methyl had a significant (p<0.05) predicted probability of being present in female enclosures. 3,3'-(1,1-Ethanediyl)bis(1H-indole) had a significant (p<0.05) probability of occurrence in male enclosures during the breeding season. Given the prevalence of these compounds, we suspect that these chemicals are important in giant panda communication. This novel sampling technique can detect volatile compounds produced by captive species and also may be a useful tool for detecting pheromones in free-ranging individuals.

Equilibrium ex vivo calibration of homogenized tissue for in vivo SPME quantitation of doxorubicin in lung tissue

The fast and sensitive determination of concentrations of anticancer drugs in specific organs can improve the efficacy of chemotherapy and minimize its adverse effects. In this paper, ex vivo solid-phase microextraction (SPME) coupled to LC-MS/MS as a method for rapidly quantitating doxorubicin (DOX) in lung tissue was optimized. Furthermore, the theoretical and practical challenges related to the real-time monitoring of DOX levels in the lung tissue of a living organism (in vivo SPME) are presented. In addition, several parameters for ex vivo/in vivo SPME studies, such as extraction efficiency of autoclaved fibers, intact/homogenized tissue differences, critical tissue amount, and the absence of an internal standard are thoroughly examined. To both accurately quantify DOX in solid tissue and minimize the error related to the lack of an internal standard, a calibration method at equilibrium conditions was chosen. In optimized ex vivo SPME conditions, the targeted compound was extracted by directly introducing a 15 mm (45 µm thickness) mixed-mode fiber into 15 g of homogenized tissue for 20 min, followed by a desorption step in an optimal solvent mixture. The detection limit for DOX was 2.5 µg g^-1 of tissue. The optimized ex vivo SPME method was successfully applied for the analysis of DOX in real pig lung biopsies, providing an averaged accuracy and precision of 103.2% and 12.3%, respectively. Additionally, a comparison between SPME and solid-liquid extraction revealed good agreement. The results presented herein demonstrate that the developed SPME method radically simplifies the sample preparation step and eliminates the need for tissue biopsies. These results suggest that SPME can accurately quantify DOX in different tissue compartments and can be potentially useful for monitoring and adjusting drug dosages during chemotherapy in order to achieve effective and safe concentrations of doxorubicin.

Procedures of determining organic trace compounds in municipal sewage sludge-a review

Sewage sludge is the largest by-product generated during the wastewater treatment process. Since large amounts of sludge are being produced, different ways of disposal have been introduced. One tempting option is to use it as fertilizer in agricultural fields due to its high contents of inorganic nutrients. This, however, can be limited by the amount of trace contaminants in the sewage sludge, containing a variety of microbiological pollutants and pathogens but also inorganic and organic contaminants. The bioavailability and the effects of trace contaminants on the microorganisms of soil are still largely unknown as well as their mixture effects. Therefore, there is a need to analyze the sludge to test its suitability before further use. In this article, a variety of sampling, pretreatment, extraction, and analysis methods have been reviewed. Additionally, different organic trace compounds often found in the sewage sludge and their methods of analysis have been compiled. In addition to traditional Soxhlet extraction, the most common extraction methods of organic contaminants in sludge include ultrasonic extraction (USE), supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), and pressurized liquid extraction (PLE) followed by instrumental analysis based on gas or liquid chromatography and mass spectrometry.

Observed and modeled effects of pH on bioconcentration of diphenhydramine, a weakly basic pharmaceutical, in fathead minnows

A need exists to better understand the influence of pH on the uptake and accumulation of ionizable pharmaceuticals in fish. In the present study, fathead minnows were exposed to diphenhydramine (DPH; disassociation constant = 9.1) in water for up to 96 h at 3 nominal pH levels: 6.7, 7.7, and 8.7. In each case, an apparent steady state was reached by 24 h, allowing for direct determination of the bioconcentration factor (BCF), blood-water partitioning (PBW,TOT), and apparent volume of distribution (approximated from the whole-body-plasma concentration ratio). The BCFs and measured PBW,TOT values increased in a nonlinear manner with pH, whereas the volume of distribution remained constant, averaging 3.0 L/kg. The data were then simulated using a model that accounts for acidification of the gill surface caused by elimination of metabolically produced acid. Good agreement between model simulations and measured data was obtained for all tests by assuming that plasma binding of ionized DPH is 16% that of the neutral form. A simpler model, which ignores elimination of metabolically produced acid, performed less well. These findings suggest that pH effects on accumulation of ionizable compounds in fish are best described using a model that accounts for acidification of the gill surface. Moreover, measured plasma binding and volume of distribution data for humans, determined during drug development, may have considerable value for predicting chemical binding behavior in fish.

In vivo and ex vivo SPME: a low invasive sampling and sample preparation tool in clinical bioanalysis

Solid phase microextraction (SPME) is well-established technology in bioanalysis. Current review discusses the features of SPME, which determine the non- or low-invasiveness of the method in biomedical analysis. In the first section we analyze the factors, which have significant influence on the SPME sampling device performance in the view of sampling safety and efficiency. In the later sections applicability of various SPME approaches for analysis of easily accessible samples routinely used for analysis (e.g., urine, blood) as well as limited availability samples (tissues) is discussed. Moreover, the examples of sampling alternative matrices such as hair, saliva, sweat or breath are presented. The advantages and limitation of the technology in the view of future development of SPME are also reviewed.

Sample preparation with solid phase microextraction and exhaustive extraction approaches: Comparison for challenging cases

In chemical analysis, sample preparation is frequently considered the bottleneck of the entire analytical method. The success of the final method strongly depends on understanding the entire process of analysis of a particular type of analyte in a sample, namely: the physicochemical properties of the analytes (solubility, volatility, polarity etc.), the environmental conditions, and the matrix components of the sample. Various sample preparation strategies have been developed based on exhaustive or non-exhaustive extraction of analytes from matrices. Undoubtedly, amongst all sample preparation approaches, liquid extraction, including liquid-liquid (LLE) and solid phase extraction (SPE), are the most well-known, widely used, and commonly accepted methods by many international organizations and accredited laboratories. Both methods are well documented and there are many well defined procedures, which make them, at first sight, the methods of choice. However, many challenging tasks, such as complex matrix applications, on-site and in vivo applications, and determination of matrix-bound and free concentrations of analytes, are not easily attainable with these classical approaches for sample preparation. In the last two decades, the introduction of solid phase microextraction (SPME) has brought significant progress in the sample preparation area by facilitating on-site and in vivo applications, time weighted average (TWA) and instantaneous concentration determinations. Recently introduced matrix compatible coatings for SPME facilitate direct extraction from complex matrices and fill the gap in direct sampling from challenging matrices. Following introduction of SPME, numerous other microextraction approaches evolved to address limitations of the above mentioned techniques. There is not a single method that can be considered as a universal solution for sample preparation. This review aims to show the main advantages and limitations of the above mentioned sample preparation approaches and the applicability and capability of each technique for challenging cases such as complex matrices, on-site applications and automation.

Profiling the physiological and molecular response to sulfonamidic drug in Procambarus clarkii

Sulfamethoxazole (SMZ) is one of the most widely employed sulfonamides. Because of the widespread use of SMZ, a considerable amount is indeed expected to be introduced into the environment. The cytotoxicity of SMZ relies mainly on arylhydroxylamine metabolites (S-NOH) of SMZ and it is associated with the production of reactive oxygen species (ROS). There is limited information about the toxic potential of SMZ at the cellular and molecular levels, especially in aquatic and/or non-target organisms. In the present study, the red swamp crayfish (Procambarus clarkii), being tolerant to extreme environmental conditions and resistant to disease, was used as a model organism to profile the molecular and physiological response to SMZ. Haemolymphatic-immunological parameters such as glucose serum levels and total haemocyte counts were altered; moreover, a significant increase in Hsp70 plasma levels was detected for the first time. Variations at the transcriptional level of proinflammatory genes (cyclooxygenase-1, COX 1, and cyclooxygenase-2, COX 2), antioxidant enzymes (glutathione-S-transferase, GST and manganese superoxide dismutase MnSOD), stress response and Fenton reaction inhibitor genes (heat-shock protein 70 HSP70, metallothionein, MT and ferritin, FT) were evaluated, and alterations in the canonical gene expression patterns emerged. Considering these results, specific mechanisms involved in maintaining physiological homeostasis and adaptation in response to perturbations are suggested.

Fish on Prozac (and Zoloft): ten years later

A decade has now passed since our research group initially reported several adverse effects of fluoxetine to aquatic organisms commonly employed for developing environmental quality criteria, evaluating whole effluent toxicity, and monitoring ambient toxicity of surface waters and sediments. Our subsequent observation of fluoxetine, sertraline and their active metabolites (norfluoxetine and desmethylsertraline, respectively) accumulating in muscle, liver and brain tissues of three different fish species from an effluent-dominated stream was termed "Fish on Prozac." Here I briefly review some scientific lessons learned from our study of antidepressants and the environment, including opportunities for research, management, environmental education and public outreach. Intrinsic chemical properties of antidepressants and other pharmaceuticals have afforded research in areas ranging from analytical chemistry and comparative pharmacology, to influences of ionization, chirality and adverse outcome pathways on hazard and risk assessment, and further promises to support sustainable molecular design of less hazardous chemicals. Using probabilistic hazard assessment and fish plasma modeling approaches, selective serotonin reuptake inhibitors and tricyclic antidepressants are predicted to result in therapeutic hazard to fish (internal fish plasma level equaling mammalian therapeutic dose) when exposed to water (inhalational) at or below 1μg/L, a common trigger value for environmental assessments. Though many questions remain unanswered, studies of antidepressants in urbanizing aquatic systems have provided, and will continue to develop, an advanced understanding of environmental hazards and risks from pharmaceuticals and other contaminants.

In vivo passive sampling of nonpolar contaminants in brown trout (Salmo trutta)

Equilibrium passive sampling through in vivo implantation can help circumvent complex extractions of biological tissues, provide more accurate information on chemical contaminant burden based on the fugacity of a chemical in an organism rather than conventional normalization to lipid content, and improve the assessment of contaminant bioaccumulation potential. Here, we explored the feasibility of in vivo implantation for the passive sampling of neutral hydrophobic contaminants through the insertion of a silicone tag into brown trout (Salmo trutta). Implanted fish from the upper reaches of the River Alna (Oslo, Norway) were relocated to a polluted section of the river for a 28 day caged exposure. "Whole fish" lipid-silicone distribution coefficients (Dlip-sil) were calculated for chlorinated compounds measured in whole fish and in silicone tags of 13 fish. Dlip-sil ranged from 13.6 to 40.0 g g(-1) for polychlorinated biphenyl congeners 28-156 (CB28 and CB156), respectively, and are in close agreement with literature in vitro lipid phase and tissue-based lipid-silicone partition coefficients. After dissection a further of eight fish, muscle and liver samples were analyzed separately. Muscle-based Dlip-sil values similar to the whole fish data were observed. However, lipid-normalized concentrations in the liver tended to be lower than in muscle for most compounds (by up to 50%). Values of whole fish Dlip-sil for brominated diphenyl ethers determined for three fish were in the range of 8.6-51 g g(-1) and in agreement with chlorinated substances. Finally, fugacity ratios calculated from equilibrium concentrations in fish-implanted and water-exposed silicone provided information on the bioaccumulation for chlorinated compounds as well as for some polycyclic aromatic hydrocarbons. Equilibrium passive sampling through in vivo implantation can allow the comparison of a chemical's activity or fugacity in biotic as well as abiotic environmental compartments and at different trophic levels up to humans.

Development and evaluation of a new in vivo solid-phase microextraction sampler

The use of solid-phase microextraction (SPME) as a nonlethal technique for in vivo sampling of pharmaceutical residue in fish tissue has been documented in the literature. However, there is need to improve its simplicity and robustness for wider applications in the laboratory and field. The objective of this research is to develop and improve the SPME device for sampling of pharmaceuticals in fish tissue. The practical application of the new device was demonstrated in the field where some wild fish (Esox masquinongy) were caught in the river and sampled by the device. The samples were analyzed using LC coupled with MS/MS (LC-MS/MS). The new in vivo SPME device with a PDMS extraction phase (sorbent) was demonstrated to a robust tool by both experts and nonexpert of the method and it is simpler than the traditional device. The detection limit of the method in gel and fish tissue was 0.01-0.26 ng/g. The interday reproducibility in gel and fish homogenized fish tissue was 8-16% RSD. This study demonstrates that the new device will provide a platform or opportunity for rapid sampling of carbamazepine, diazepam, and nordiazepam in fish muscle with acceptable precision.

In vivo solid-phase microextraction for tissue bioanalysis

Conventional in vitro or ex vivo bioanalytical quantitative sample preparation methods for the determination of compounds in biological tissues are often coupled with challenges in obtaining an assay representative of the system of interest. The rising interest in in vivo microsampling bioanalytical methods is due to the unique advantages they offer over their in vitro counterparts. In vivo solid-phase microextraction (SPME), a diffusion-based microsampling tool, has been successfully applied in recent studies to various biological systems. This review presents recent trends in tissue bioanalysis using in vivo SPME as a sample preparation tool. Efforts were made to discuss the various bioapplications of the method while highlighting possible strategies for improved sensitivity where needed. In vivo SPME devices currently employed for the various applications have also been described. In addition, we highlight selectivity of a new class of biocompatible coatings that can potentially improve the coverage of metabolites for untargeted metabolomics.

Field and laboratory fish tissue accumulation of the anti-convulsant drug carbamazepine

Understanding the potential for human and veterinary pharmaceuticals to accumulate in the tissues of biota is a topic of increasing importance in the pharmaceutical risk assessment process. However, few data are available in the literature that compare the ability of laboratory bioconcentration studies to predict field tissue concentrations. To begin to address this data gap, bioconcentration factors (BCF) for carbamazepine (CBZ), a human anticonvulsant that modulates Na+ channels, were determined using laboratory experiments with Pimephales notatus and Ictalurus punctatus. These data were compared to field derived bioaccumulation factors (BAFs) for Oreochromis niloticus from the Denton, Texas Wastewater Treatment Plant. The 42 d kinetic BCFs (BCFk) for white muscle and liver of P. notatus were 1.9 and 4.6, respectively, while the white muscle, liver, brain, and plasma BCFk's of I. punctatus were 1.8, 1.5, 1.6, and 7.1, respectively. Field derived BAF values (2.5-3.8) for O. niloticus were similar to those derived in laboratory studies. Partitioning values between blood plasma and individual tissues were calculated for I. punctatus and O. niloticus, with the values indicating that tissue levels of carbamazepine are similar or slightly higher than plasma concentrations. Collectively these data suggest that the fish laboratory BCF and field derived BCF/BAF values for carbamazepine are similar and much lower than the European Union regulatory threshold of 2000 for designation of a "B" substance.

Internal benchmarking improves precision and reduces animal requirements for determination of fish bioconcentration factors

The enactment of new chemical regulations has generated a large need for the measurement of the fish bioconcentration factor (BCF). Past experience shows that the BCF determination lacks precision, requires large numbers of fish, and is costly. A new protocol was tested that shortens the experiment from up to 12 weeks for existing protocols to 2 weeks and reduces the number of fish by a factor of 5, while introducing internal benchmarking for the BCF determination. Rainbow trout were simultaneously exposed to 11 chemicals. The BCFs were quantified using one of the test chemicals, musk xylene, as a benchmark. These were compared with BCFs measured in a parallel experiment based on the OECD 305 guideline. The agreement was <20% for five chemicals and between 20%-25% for two further, while two chemicals lay outside the BCF operating window of the experiment and one was lost due to analytical difficulties. This agreement is better than that observed in a BCF Gold Standard Database. Internal benchmarking allows the improvement of the precision of BCF determination in parallel to large reduction in costs and fish requirements.