Solid-phase Microextraction In Combination Research Articles

Determination of volatiles in beer using solid-phase microextraction in combination with gas chromatography/mass spektrometry

Headspace solid phase microextraction and purge and trap analysis were used for the determination of volatiles in beer. These methods were compared with the analysis of unconcentrated gas phase and liquid extraction. Solid phase microextraction proved to be the most useful and was investigated more closely. Volatiles were isolated by the means of different combinations of sorbents, sorption was performed at various temperatures and times. The addition of salt to the sample and stirring of the sample were examined to enhance the analyte concentration in the gas phase. Ultrasonic bath and filtration were tested to remove carbon dioxide. Not all methods improved the sorption of volatiles. Stirring was characterised by low repeatability and ultrasonic bath causes to the loss of volatile analytes. Distribution constants of volatiles depend on their boiling points and thus different sorption temperatures are suitable for different substances.

Analysis of volatile human urinary metabolome by solid-phase microextraction in combination with gas chromatography–mass spectrometry for biomarker discovery: Application in a pilot study to discriminate patients with renal cell carcinoma

A new and simple analytical approach consisting of headspace-solid phase microextraction (HS-SPME) sampling coupled with gas chromatography-ion trap/mass spectrometry (GC-IT/MS) was developed to study the volatile human urinary metabolome. A central composite design (CCD) was used in the optimisation of extraction conditions. Fibre selection and evaluation of pH influence were performed using an univariate mode and the influence of other parameters, such as the time and temperature of extraction, time of incubation and salt addition, that affect the efficiency of the SPME sampling, was carried out using a CCD. With a sample volume of 2mL, the optimal conditions in terms of total response values and reproducibility were achieved by performing analyses with a divinylbenzene/polydimethylsiloxane (DVB/PDMS) fibre, in an acidic pH (pH 2) with the addition of 0.59g of NaCl, allowing the sample to equilibrate for 9min and extracting at 68°C for 24min. The applicability of the optimised method was then tested in a pilot non-target analysis of urine samples obtained from patients with renal cell carcinoma (RCC) and healthy individuals. Chemometric unsupervised analyses performed on the volatile pattern acquired for these samples clearly showed the potential of volatile urinary metabolome to discriminate between RCC and control patients.

Characterization of Novel Single-Variety Oxygenated Sesquiterpenoid Hop Oil Fractions via Headspace Solid-Phase Microextraction and Gas Chromatography–Mass Spectrometry/Olfactometry

The volatile composition of novel varietal oxygenated sesquiterpenoid hop oil fractions ("spicy essences") was characterized by headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry. Oxygenated sesquiterpenes represent the major chemical compound class, accounting for at least 65% of the total volatile fraction. In addition to oxygenated sesquiterpenes, spicy hop essences consist of several ketones, sesquiterpene and monoterpene hydrocarbons, and a relatively high number of unidentified compounds. On the basis of their relative composition, spicy hop essences can be fully differentiated according to their varietal origin. Multidimensional gas chromatography in combination with time-of-flight mass spectrometry on spicy hop essence cv. Spalter Select further demonstrated the enormous complexity of this particular hop oil fraction. The aromagram obtained via gas chromatography-olfactometry comprised nine odor-active regions described in terms of "citrus", "green", "haylike", "earthy", "woody", and "spicy". 2-Undecanone, 2-tridecanone, γ-cadinene, α-calacorene, calarene, humuladienone, caryolan-1-ol, caryophyllene oxide enantiomers, and humulene epoxide II are tentatively identified in the odor-active zones.

Combined solid‐phase microextraction and high‐performance liquid chromatography with ultroviolet detection for simultaneous analysis of clenbuterol, salbutamol and ractopamine in pig samples

A simple and sensitive method based on the combination of solid-phase microextraction (SPME) and high-performance liquid chromatography with ultroviolet detection was developed for the simultaneous determination of clenbuterol, salbutamol and ractopamine in pig samples. Parameters of the SPME procedure affecting extraction efficiency, such as the type of fiber, extraction time, extraction temperature, ion strength, pH of sample and stirring rate, were optimized. The developed method was validated according to the International Conference on Harmonization guidelines. The calibration curves were linear over a range of 0.5-50 µg/L for clenbuterol and ractopamine, and 0.2-20 µg/L for salbutamol. The limits of detection were 0.1 µg/L for clenbuterol, 0.05 µg/L for salbutamol and 0.1 μg/L for ractopamine, respectively. The averages of intra- and inter-day accuracy ranged from 79.8 to 92.4%. The intra-day and inter-day precision were below 9.6% for the three analytes. This method exhibited the advantages of simplicity, rapidity and low solvent consumption, and was suitable for the monitoring of β2 -agonists residue in pig samples.

Improvements and application of a modified gas chromatography atomic fluorescence spectroscopy method for routine determination of methylmercury in biota samples

Improvements to the application of a combined solid-phase microextraction followed by gas chromatography coupled to pyrolysis and atomic fluorescence spectrometry method (SPME–GC–AFS) for methylmercury (MeHg) determination in biota samples are presented. Our new method includes improvements in the methodology of determination and the quantification technique. A shaker instead of a stirrer was used, in order to reduce the possibility of sample contamination and to simplify cleaning procedures. Then, optimal rotation frequency and shaking time were settled at 800rpm and 10min, respectively. Moreover, the GC–AFS system was equipped with a valve and an argon heater to eliminate the effect of the decrease in analytical signal caused by the moisture released from SPME fiber. For its determination, MeHg was first extracted from biota samples with a 25% KOH solution (3h) and then it was quantified by two methods, a conventional double standard addition method (AC) and a modified matrix-matched calibration (MQ) which is two times faster than the AC method. Both procedures were successfully tested with certified reference materials, and applied for the first time to the determination of MeHg in muscle samples of goosander (Mergus merganser) and liver samples of white-tailed eagle (Haliaeetus albicilla) with values ranging from 1.19 to 3.84mg/kg dry weight (dw), and from 0.69 to 6.23mgkg−1 dw, respectively.

Determination of N,N-dimethyltryptamine in beverages consumed in religious practices by headspace solid-phase microextraction followed by gas chromatography ion trap mass spectrometry

A novel analytical approach combining solid-phase microextraction (SPME)/gas chromatography ion trap mass spectrometry (GC-IT-MS) was developed for the detection and quantification N,N-dimethyltryptamine (DMT), a powerful psychoactive indole alkaloid present in a variety of South American indigenous beverages, such as ayahuasca and vinho da jurema. These particular plant products, often used within a religious context, are increasingly consumed throughout the world following an expansion of religious groups and the availability of plant material over the Internet and high street shops. The method described in the present study included the use of SPME in headspace mode combined GC-IT-MS and included the optimization of the SPME procedure using multivariate techniques. The method was performed with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber in headspace mode (70min at 60°C) which resulted in good precision (RSD<8.6%) and accuracy values (71–109%). Detection and quantification limits obtained for DMT were 0.78 and 9.5mgL−1, respectively and good linearity (1.56–300mgL−1, r2=0.9975) was also observed. In addition, the proposed method showed good robustness and allowed for the minimization of sample manipulation. Five jurema beverage samples were prepared in the laboratory in order to study the impact of temperature, pH and ethanol on the ability to extract DMT into solution. The developed method was then applied to the analysis of twelve real ayahuasca and vinho da jurema samples, obtained from Brazilian religious groups, which revealed DMT concentration levels between 0.10 and 1.81gL−1.

Highly sensitive determination of chlorpromazine by electrochemically treated pencil graphite fiber as both solid-phase microextraction fiber and working electrode for use in voltammetry method

This paper describes the electrochemical modification of a pencil graphite fiber used as both a solid phase microextraction fiber and a working electrode in differential pulse voltammetry (DPV). The combination of solid phase microextraction and DPV was applied as a highly selective and sensitive method for the determination of chlorpromazine. The pencil graphite fibers were electrochemically treated in phosphoric acid and sodium hydroxide solutions. Experimental parameters influencing the extraction efficiency of SPME, such as NaOH concentration, ionic strength of the sample, stirring rate, and extraction time were studied and optimized. Under the optimum conditions, analytical parameters such as linearity, precision and limit of detection were evaluated. The linear dynamic range was from 0.35 to 35 μg L−1 and the limit of detection was 0.2 μg L−1. Intra- and inter-day precision of the method was satisfactory with a relative standard deviation of 2.2 and 4.8%, respectively. The method was successfully applied for the determination of chlorpromazine in human plasma and urine.

Solid‐phase microextraction combined with comprehensive two‐dimensional gas chromatography for fatty acid profiling of cell wall phospholipids

The combination of solid-phase microextraction (SPME) with comprehensive two-dimensional gas chromatography is evaluated here for fatty acid (FA) profiling of the glycerophospholipid fraction from human buccal mucosal cells. A base-catalyzed derivatization reaction selective for polar lipids such as glycerophospholipid was adopted. SPME is compared to a miniaturized liquid-liquid extraction procedure for the isolation of FA methyl esters produced in the derivatization step. The limits of detection and limits of quantitation were calculated for each sample preparation method. Because of its lower values of limits of detection and quantitation, SPME was adopted. The extracted analytes were separated, detected, and quantified by comprehensive two-dimensional gas chromatography with flame ionization detection (FID). The combination of SPME and comprehensive two-dimensional gas chromatography with FID, using a selective derivatization reaction in the preliminary steps, proved to be a simple and fast procedure for FA profiling, and was successfully applied to the analysis of adult human buccal mucosal cells.

Measurement of pentane in expiratory gas during rabbit hepatic ischemia/reperfusion by solid-phase microextraction and gas chromatography–mass spectrometry (SPME GC/MS)

The aim of this study was to determine the changes in the pentane concentration of expiratory gas as well as the relationship between this pentane concentration and hepatic oxidative stress during rabbit hepatic ischemia/reperfusion using solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC/MS). 45 white male rabbits with body weights between 2.5 and 3.0 kg were randomly assigned to the following three groups: the 10 min ischemia group (group S); the 20 min ischemia group (group M); or the 30 min ischemia group (group L). Expiratory gases were collected prior to ischemia (T0) and for 1, 10, 20, 30, 60 and 120 min (T1–T6) following reperfusion. Pentane concentrations were determined using SPME and GC/MS. In addition, arterial blood samples were collected, and serum aminotransferase (AST) and malondialdehyde (MDA) concentrations were measured. In the three groups, the pentane concentrations of the expiratory gases at points T1 and T2 were significantly increased (P < 0.05) compared with those at point T0, and the serum AST and MDA concentrations at points T5 and T6 were also significantly increased (P < 0.05) compared with those at point T0. Therefore, the use of SPME in combination with GC/MS represents an improved anesthesia system that can be used to continuously measure the concentration of pentane in expiratory gases, which can reflect the degree of oxidative stress during hepatic ischemia/reperfusion.

Abstract 1264: Small volatile organic compounds extracted from advanced pancreatic cancer patient blood samples: Development towards a diagnostic method

Abstract Introduction Analysis of biological samples for volatile organic compound (VOC) profiles or fingerprints can potentially be utilized as a non-invasive, early stage diagnostic tool for disease related to metabolic processes. A hypothesis was presented in 1989 that dogs could detect malignant tumors by scent and several studies of canine scent detection for cancer followed. Our team has taken an analogous approach using solid phase microextraction in combination with capillary gas chromatography time of flight mass spectrometry (SPME GC-TOFMS) in place of canine scent detection to discover indicators for pancreatic cancer, a deadly cancer difficult to detect in its early development stage. VOCs are not commonly considered in “biomarker” analysis of clinical samples which usually require extensive pre-processing. The VOC fingerprint from a biological sample presumes many such substances are products, by-products, and waste resulting from human metabolism (and/or symbiotic microbiom) of nutrients and intermediates from endogenous processes, absorbed environmental contaminants, and endo/exogenous bacterial metabolism. Methods IRB approval was obtained to enroll patients with advanced pancreatic cancer and healthy volunteers. Blood was collected in pre-conditioned vacutainers from 11 patients and 5 healthy volunteers, all non-smokers, no chemotherapy in preceding 5 days, and analyzed within 2 weeks. SPME GC-TOFMS is a means for eliminating the biological matrix and pre-concentrating specific ranges of complex volatile fraction polarities at low concentrations and a very sensitive analytical instrumental platform for the characterization of VOC chromatographic profiles extracted from the 3ml blood samples. Multivariate statistical methods were used to analysis retention time exact mass observations and integrated peak areas. Results Even with the numerous variables contributing to an already diverse underlying metabolism of each participant, our chemometric approach did discriminate between “healthy” volunteers and the cancer patients with a 5% prediction error using a “leave one out” statistical analysis for 37 samplesb from the 16 subjects. Key retention time and exact mass observations from a fiber specific SPME were associated to preliminary molecule identifications via NIST data base searches. Our procedures for system tune, calibration, and monitoring achieved a response stability over a 1 month period of ∼10% rsd and accurate mass measurement of at least 5 mDa (30 - 300 Da) using benzene-d6, BFB, and naphthalene-d8. Conclusions VOC fingerprints from a SPME GC-TOFMS analysis of blood can be successful in discovering differentiating indicators related to APC. Future work will involve other SPME fibers and more samples. (Supported by the IBIS &amp; Scottsdale Health Care Foundations) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1264. doi:1538-7445.AM2012-1264

Solid Phase Microextraction Gas Chromatography Mass Spectroscopy Analysis of Confectionery Volatiles

Identification of the analytes present in the volatile portion of a number of confectionaries was made using solid phase microextraction in combination with gas chromatography mass spectroscopy. This represents a first step in formulating a database of confectionary volatiles, which considering the recent problems with food adulteration should prove useful. Keywords: Confectionary, gas chromatography, mass spectroscopy, spme, flavor component, fingerprint, GC-MS, volatiles, ion chromatogram, flavor

Comparison of solid phase microextraction versus spectroscopic techniques for binding studies of carbamazepine

The binding of carbamazepine to human serum albumin was studied in vitro using solid-phase microextraction (SPME) with liquid chromatography-ultraviolet detection (LC-UV), as well as spectroscopic fluorescence and nuclear magnetic resonance ((1)H NMR) techniques. We were able to recognize one high affinity binding site with both fluorescence and SPME methods. Additionally, SPME experiment showed the existence of one lower affinity binding site for carbamazepine at the range of concentrations studied with fluorescence. The analysis of Hill's plot indicated positive cooperativity between drugs located in these two binding sites. Two low affinity-binding sites have been found with SPME-LC-UV analysis performed in parallel to (1)H NMR study, which does not show any complex formation. In conclusion, the results of the studies with carbamazepine as a model drug showed the advantages of simultaneous use of solid phase microextraction and spectroscopic methods in protein binding studies and indicated complementary information, which can be obtained with the use of SPME. Furthermore, we show that SPME in combination with liquid chromatography-mass spectrometry permitted direct in vitro determination of plasma-protein binding and direct in vivo evaluation of inter-animal variability in free concentrations of carbamazepine at physiologically relevant concentrations, the type of experiments typically inaccessible by spectroscopic techniques due to poor sensitivity and different mode of implementation.

Semi-automated in vivo solid-phase microextraction sampling and the diffusion-based interface calibration model to determine the pharmacokinetics of methoxyfenoterol and fenoterol in rats

In vivo solid-phase microextraction (SPME) can be used to sample the circulating blood of animals without the need to withdraw a representative blood sample. In this study, in vivo SPME in combination with liquid–chromatography tandem mass spectrometry (LC–MS/MS) was used to determine the pharmacokinetics of two drug analytes, R,R-fenoterol and R,R-methoxyfenoterol, administered as 5mgkg−1i.v. bolus doses to groups of 5 rats. This research illustrates, for the first time, the feasibility of the diffusion-based calibration interface model for in vivo SPME studies. To provide a constant sampling rate as required for the diffusion-based interface model, partial automation of the SPME sampling of the analytes from the circulating blood was accomplished using an automated blood sampling system. The use of the blood sampling system allowed automation of all SPME sampling steps in vivo, except for the insertion and removal of the SPME probe from the sampling interface. The results from in vivo SPME were compared to the conventional method based on blood withdrawal and sample clean up by plasma protein precipitation. Both whole blood and plasma concentrations were determined by the conventional method. The concentrations of methoxyfenoterol and fenoterol obtained by SPME generally concur with the whole blood concentrations determined by the conventional method indicating the utility of the proposed method. The proposed diffusion-based interface model has several advantages over other kinetic calibration models for in vivo SPME sampling including (i) it does not require the addition of a standard into the sample matrix during in vivo studies, (ii) it is simple and rapid and eliminates the need to pre-load appropriate standard onto the SPME extraction phase and (iii) the calibration constant for SPME can be calculated based on the diffusion coefficient, extraction time, fiber length and radius, and size of the boundary layer. In the current study, the experimental calibration constants of 338.9±30mm−3 and 298.5±25mm−3 are in excellent agreement with the theoretical calibration constants of 307.9mm−3 and 316.0mm−3 for fenoterol and methoxyfenoterol respectively.

ChemInform Abstract: Determination of Chemical Warfare Agents and Related Compounds in Environmental Samples by Solid‐Phase Microextraction with Gas Chromatography

AbstractReview: 118 refs.

Investigation of the Volatile Composition of Pinotage Wines Fermented with Different Malolactic Starter Cultures Using Comprehensive Two-Dimensional Gas Chromatography Coupled to Time-of-Flight Mass Spectrometry (GC×GC-TOF-MS)

Headspace solid phase microextraction in combination with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (HS-SPME-GC × GC-TOF-MS) was used for the detailed investigation of the impact of malolactic fermentation (MLF) using three commercial Oenococcus oeni strains on the volatile composition of Vitis vinifera cv. Pinotage wines. GC × GC allowed the identification of 115 volatile compounds, including both major constituents and trace-level compounds, in a single analysis. A number of compounds differing in mean concentration levels between the control wines and those fermented with different starter cultures were shown for the first time to be influenced by MLF and/or the bacterial strain. Principal component analysis (PCA) provided excellent separation between the wines fermented with different MLF starter cultures and the control wine. Significantly different levels for some volatile compounds in wines fermented with one of the LAB starter cultures could be indicative of metabolic differences of this strain.

Investigation of urinary volatile organic metabolites as potential cancer biomarkers by solid-phase microextraction in combination with gas chromatography-mass spectrometry

Background:Non-invasive diagnostic strategies aimed at identifying biomarkers of cancer are of great interest for early cancer detection. Urine is potentially a rich source of volatile organic metabolites (VOMs) that can be used as potential cancer biomarkers. Our aim was to develop a generally reliable, rapid, sensitive, and robust analytical method for screening large numbers of urine samples, resulting in a broad spectrum of native VOMs, as a tool to evaluate the potential of these metabolites in the early diagnosis of cancer.Methods:To investigate urinary volatile metabolites as potential cancer biomarkers, urine samples from 33 cancer patients (oncological group: 14 leukaemia, 12 colorectal and 7 lymphoma) and 21 healthy (control group, cancer-free) individuals were qualitatively and quantitatively analysed. Dynamic solid-phase microextraction in headspace mode (dHS-SPME) using a carboxen-polydimethylsiloxane (CAR/PDMS) sorbent in combination with GC-qMS-based metabolomics was applied to isolate and identify the volatile metabolites. This method provides a potential non-invasive method for early cancer diagnosis as a first approach. To fulfil this objective, three important dHS-SPME experimental parameters that influence extraction efficiency (fibre coating, extraction time and temperature of sampling) were optimised using a univariate optimisation design. The highest extraction efficiency was obtained when sampling was performed at 50°C for 60 min using samples with high ionic strengths (17% sodium chloride, w v−1) and under agitation.Results:A total of 82 volatile metabolites belonging to distinct chemical classes were identified in the control and oncological groups. Benzene derivatives, terpenoids and phenols were the most common classes for the oncological group, whereas ketones and sulphur compounds were the main classes that were isolated from the urine headspace of healthy subjects. The results demonstrate that compound concentrations were dramatically different between cancer patients and healthy volunteers. The positive rates of 16 patients among the 82 identified were found to be statistically different (P<0.05). A significant increase in the peak area of 2-methyl-3-phenyl-2-propenal, p-cymene, anisole, 4-methyl-phenol and 1,2-dihydro-1,1,6-trimethyl-naphthalene in cancer patients was observed. On average, statistically significant lower abundances of dimethyl disulphide were found in cancer patients.Conclusions:Gas chromatographic peak areas were submitted to multivariate analysis (principal component analysis and supervised linear discriminant analysis) to visualise clusters within cases and to detect the volatile metabolites that are able to differentiate cancer patients from healthy individuals. Very good discrimination within cancer groups and between cancer and control groups was achieved.

Electrophysiological and behavioral identification of a volatile blend involved in host location of female strawberry sap beetle, Stelidota geminata

The strawberry sap beetle (SSB), Stelidota geminata (Say) (Coleoptera: Nitidulidae), is a serious direct pest of strawberries in the northeastern USA. To date, however, no food or pheromone-based attractants for SSB have been identified. A combination of solid-phase microextraction, adsorbent sampling, gas chromatography coupled with electroantennographic detection (GC–EAD), and gas chromatography–mass spectrometry was used to identify volatile compounds from strawberry fruit acting as behavioral attractants for female SSB. Consistent EAD activity was obtained for 16 ester compounds. In Y-tube olfactometer bioassays, the blend of these 16 compounds mixed at a ratio observed from strawberry headspace was significantly more attractive to adult female SSB than a control. Female SSB showed no difference in response levels between the 16-component blend and a strawberry volatile adsorbent extract. Our data indicate that the combination of the ethyl acetate with some or all of the remaining 15 compounds is necessary for this ester blend to be attractive to female SSB. Previously identified host volatiles found for other species of sap beetles included mostly alcohols associated with over-ripe fruit rather than the esters identified from ripe strawberries for SSB. A highly attractive synthetic food odor will be useful for developing new management options for SSB.

Effects of lard on the formation of volatiles from the Maillard reaction of cysteine with xylose

The presence of lipid oxidation products in the Maillard reaction pathway is of particular interest today. The objective of this study was to investigate the effect of lard and its oxidation products on the formation of volatiles from cysteine and xylose model systems. Headspace volatiles generated in reaction mixtures were examined by solid-phase microextraction in combination with gas chromatography-mass spectrometry. The addition of lipid had a suppressing effect on most of the sulfur-containing compounds derived from the reaction between cysteine and xylose, especially for 2-methyl-3-furanthiol, 2-furanmethanethiol, 2-methylthiophene, and 3-methylthiophene. One of the intermediates-furfural-was also formed in much lower concentration when lard was present. In addition, cysteine and xylose modified lipid oxidation pathways, so that lipid-derived alcohols, alkylfurans and aliphatic acids were formed rather than aldehydes. Compared with the lard heated alone, most aldehydes were formed at lower levels in the lard-containing reaction mixtures, and several aldehydes including hexanal, heptanal, (2E)-heptenal and (2E,4E)-heptadienal were absent. The addition of lipid was inhibitory to the formation of most sulfur-containing compounds in the Maillard reaction. Furthermore, Maillard reaction products influenced the formation of products from lipid oxidation.

The Evaluation of Human Hand Odor Volatiles on Various Textiles: A Comparison Between Contact and Noncontact Sampling Methods*,†

The focus of this study is to compare contact and noncontact human scent collection procedures across an array of textiles (cotton, rayon, polyester, and wool) to determine an optimized collection method for human scent evidence. Six subjects were sampled in triplicate for each textile and collection mode, and the samples were then analyzed through headspace solid-phase micro-extraction in combination with gas chromatography/mass spectrometry (SPME-GC/MS). Contact sampling with cotton material has been shown to be the collection method that yielded the greatest number of volatile compounds and the highest scent mass amounts. Through Spearman rank correlations, it was shown that an individual's scent profile is more reproducible within samples collected on the same textile type than between different materials. Furthermore, contact sampling with cotton fabric demonstrated the greatest reproducibility producing the lowest amount of type I and type II errors with 90.85% of the samples distinguished at the 0.9 match/no match threshold.

Passive dosing: An approach to control mutagen exposure in the Ames fluctuation test

One of the major challenges for mutagenicity assessment of environmental samples and individual compounds for example in the Ames fluctuation test (AFT) is the establishment and control of a well defined exposure concentration. Thus, a combination of passive dosing with silicone O-rings (SRs) together with an analytical confirmation of the freely dissolved concentration (FDC) is presented. FDCs are often determined with a combination of solid phase micro-extraction (SPME) with gas chromatography (GC). For compounds with poor performance in GC, a high performance liquid chromatography–mass spectrometry (HPLC–MS) analysis of bi-distilled water dosed with identically loaded SRs is suggested to avoid interference of the bacterial culture. The approach was tested for six amino-, nitro-, and keto-substituted polycyclic aromatic compounds with a log K OW range of 2.5–5.1 without metabolic activation. The method provided reliable concentration-effect relationships and freely dissolved 50% effect concentrations (DEC 50) 3–33 times lower than nominal effect concentrations (NEC 50) derived in parallel solvent-dosed AFT. Partition coefficients and NEC 50/DEC 50 ratios were well correlated with lipophilicity.