Analytical method for the determination of trace levels of steroid hormones and corticosteroids in soil, based on PLE/SPE/LC-MS/MS

The aim of this study was to develop an efficient, sensitive and reliable analytical method for the determination of traces of steroid hormones (including oestrogen, androgens and progestagens) and corticosteroids in soil. A method of sample preparation involving pressurized liquid extraction (PLE) and solid-phase extraction (SPE) was developed for the determination of six steroids and five corticosteroids in soils, followed by analysis by liquid chromatography-tandem mass spectrometry. The conditions employed for PLE involved acetone/methanol (50:50) as the extracting solvent, a temperature of 80 °C, two cycles and a static time of 5 min. The extraction was followed by a SPE clean-up based on a polymeric phase. With use of protocol, a residual matrix effect was, however, highlighted. The limit of detection in soil was 0.08–0.89 ng/g for steroids and 0.09–2.84 ng/g for corticosteroids.     

Extraction and clean-up strategies for the analysis of poly- and perfluoroalkyl substances in environmental and human matrices

The rapidly expanding field of per- and polyfluorinated alkyl substances (PFASs) research has resulted in a wide range of analytical methodologies to determine the human and environmental exposure to PFASs. This paper reviews the currently applied techniques for sample pre-treatment, extraction and clean-up for the analysis of ionic and non-ionic PFASs in human and environmental matrices. Solid phase extraction (SPE) is the method of choice for liquid samples (e.g. water, blood, serum, plasma), and may be automated in an on-line set-up for (large volume) sample enrichment and sample clean-up. Prior to SPE, sample pre-treatment (filtration or centrifugation for water or protein precipitation for blood) may be required. Liquid-liquid extraction can also be used for liquid samples (and does not require above mentioned sample pretreatment). Solid-liquid extraction is the commonly applied method for solid matrices (biota, sludge, soil, sediment), but automation options are limited due to contamination from polytetrafluorethylene tubings and parts applied in extraction equipment. Air is generally preconcentrated on XAD-resins sandwiched between polyurethane foam plugs. Clean-up of crude extracts is essential for destruction and removal of lipids and other co-extractives that may interfere in the instrumental determination. SPE, (fluorous) silica column chromatography, dispersive graphitized carbon and destructive methods such as sulphuric acid or KOH treatment can be applied for clean-up of extracts. Care should be taken to avoid contamination (e.g. from sample bottles, filters, equipment) and losses of PFASs (e.g. adsorption, volatilization) during sampling, extraction and clean-up. Storage at -20 degrees C is generally appropriate for conservation of samples.     

Suitability of selective pressurized liquid extraction combined with gas chromatography-ion-trap tandem mass spectrometry for the analysis of polybrominated diphenyl ethers

A one-step extraction and clean-up method using pressurized liquid extraction (PLE) (selective PLE) combined with gas chromatography-ion-trap tandem mass spectrometry (GC-ITMS-MS) was evaluated for the analysis of polybrominated diphenyl ethers (from tri- to hepta-PBDEs) at low concentrations in fish and shellfish samples. To this end, the performance of an on-line PLE extraction/clean-up method and of a classical Soxhlet extraction and clean-up method using a multi-layer modified silica column were compared. The two sample treatment methods provided similar results, although an important reduction in the sample treatment time (40 min per sample) was achieved using the selective PLE method. In addition, the suitability of the PLE combined with GC-ITMS-MS method was evaluated by comparing the results obtained in the analysis of fish samples with those obtained by gas chromatography-high resolution mass spectrometry (GC-HRMS). Good agreement between both techniques was obtained with differences between the mean values of less than 16%. The selective PLE method coupled to GC-ITMS-MS produced accurate results for PBDE determination with low limits of detection (1.0-16.8 pg g⁻¹ wet weight) and quantification (3.1-51 pg g⁻¹ wet weight) as well as good precision (RSD < 16%). This method has been applied to the analysis of PBDEs in fish and shellfish samples collected at fish markets in Catalonia (NE Spain).     

Validation of the CALUX bioassay for PCDD/F analyses in human blood plasma and comparison with GC-HRMS

Following the dioxin crisis of 1999, several studies were conducted to assess the impact of this crisis on the dioxin body burden in the Belgian population. The Scientific Institute of Public Health identified a population from whom plasma samples were available and from whom, during the follow up survey, plasma samples were obtained in 2000. In total, 496 samples were collected for GC-HRMS and CALUX analyses to verify statistical assessment conclusions. This study was seen as an opportunity to validate the CALUX bioassay for biological sample analysis and to compare toxic equivalency (TEQ) values obtained by the reference GC-HRMS technique and by the screening method. This article focuses on the validation results of the CALUX bioassay for the analyses of the dioxin fractions of blood plasma. The sample preparation is based on a liquid–liquid extraction, followed by an acid silica in series with an activated carbon clean-up. A good recovery (82%) and reproducibility (coefficient of variation less than 25%) were found for this method. Based on 341 plasma samples, a significant correlation was established between the bioassay and chemical method (R = 0.64). However, a proportional systematic error was observed when the results obtained with the CALUX bioassay were regressed with the results from the GC-HRMS analyses. The limit of quantification (LOQ) used to calculate TEQ values from the GC-HRMS determinations, the use of the relative potency values instead of the toxic equivalent factor and the potential of CALUX bioassay to measure all compounds with affinity for the AhR may partly explain this proportional systematic error. Nevertheless, the present results suggest that the CALUX bioassay could be a promising valid screening method for human blood plasma analyses.     

母乳中多种含卤持久性有机污染物的联合检测方法

建立了母乳中多种含卤持久性有机污染物(POPs)的联合检测方法,目标化合物主要包括六溴环十二烷(HBCDs)、多溴联苯醚(PBDEs)、多氯联苯(PCBs)和有机氯农药(OCPs)等.样品的前处理采用液液萃取、凝胶渗透色谱(GPC)净化和固相萃取(SPE)等技术,目标化合物经气相色谱-质谱联用仪(GC-MS)、液相色谱-三重四极杆串联质谱联用仪(LC-MS/MS)和气相色谱-三重四极杆串联质谱联用仪(GC-MS/MS)等进行检测.样品通过GPC除去脂肪,然后经SPE柱进一步净化并进行多组分分离,极大程度地减小了生物样品中复杂基质的干扰,适合样品量相对较小的人体样本中多种超痕量POPs的分析.应用灵敏度高、选择性更好的GC-MS/MS对样品中的PCBs和OCPs等进行分析,进一步降低基质的干扰.方法经过小牛血清加标实验验证,稳定可靠.POPs的加标回收率分别为88.7％～98.8％(PBDEs), 88.5％～92.5％(HBCDs), 67.9％～82.3％(PCBs)和81.7％～116.1％(OCPs),方法检出限分别为0.13～1.8 pg/mL(PBDEs), 0.31～1.2 pg/mL(HBCDs), 0.22～1.4 pg/mL(PCBs)和0.20～1.5 pg/mL(OCPs).采用本方法对潍坊地区20例母乳样品进行分析,结果显示,潍坊市母乳中HBCDs, PBDEs, PCBs、HCHs和DDTs的中值浓度分别为2.86, 7.76, 8.84、140和503 ng/g 脂重,此浓度水平与国内其它地区人群相当.     

Sample handling strategies for the determination of persistent trace organic contaminants from biota samples

Even after emergence of most advanced instrumental techniques for the final separation, detection, identification and determination of analytes, sample handling continues to play a basic role in environmental analysis of complex matrices. In fact, sample preparation steps are often the bottleneck for combined time and efficiency in many overall analytical procedures. Thus, it is not surprising that, in the last two decades, a lot of effort has been devoted to the development of faster, safer, and more environment friendly techniques for sample extraction and extract clean up, prior to actual instrumental analysis. This article focuses on the state of the art in sample preparation of environmental solid biological samples dedicated to persistent organic pollutants (POPs) analysis. Extraction techniques such as Soxhlet extraction, sonication-assisted extraction, supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), pressurised liquid extraction (PLE) and matrix solid-phase dispersion (MSPD) are reviewed and their most recent applications to the determination of POPs in biota samples are provided. Additionally, classical as well as promising novel extraction/clean-up techniques such as solid phase microextraction (SPME) are also summarized. Finally, emerging trends in sample preparation able to integrate analytes extraction and their adequate clean-up are presented.     

Selective pressurized liquid extraction for multi-residue analysis of organochlorine pesticides in soil

A selective pressurized liquid extraction (SPLE) procedure capable of performing simultaneous extraction and clean-up has been demonstrated for multi-residue analysis of organochlorine pesticides (OCPs) in soil. The final method was performed at 100 degrees C for 3 x 10 min using acetone/n-heptane (1:1, v/v). Florisil was placed inside the extraction cell downstream the sample to remove interfering compounds. Extraction of two soil samples by SPLE gave a recovery which was over 80% for beta-endosulfan, endosulfan sulfate, p,p'-DDT and p,p'-DDE compared to PLE with off-line clean-up. The same trend was observed when applying the SPLE method to a certified reference soil sample (CRM 811-050) containing 13 OCPs, where the SPLE method gave 80-90% recovery vis-à-vis the PLE method with off-line clean-up. Feasibility of the SPLE method was further demonstrated by applying it to five real soil samples collected in Ethiopia.     

Development of a pressurized liquid extraction and clean-up procedure for the determination of alpha-endosulfan, beta-endosulfan and endosulfan sulfate in aged contaminated Ethiopian soils

Pressurized liquid extraction (PLE) was investigated for the extraction of two endosulfan isomers and their metabolite from two real contaminated soil samples. PLE for 3x10min at 100 degrees C was proven to be more exhaustive than Soxhlet extraction (SOX) in one soil sample. On the other soil sample investigated the method was found to be equally exhaustive as SOX. The use of hazardous organic solvents such as n-hexane, toluene, and diethyl ether has been avoided in PLE and clean-up. Instead less toxic solvents have been used both at the extraction step (acetone/n-heptane) and clean-up step (ethyl acetate/n-heptane). A column Florisil clean-up procedure that consumes relatively low solvent volumes has been optimized and applied to purify soil extracts. The developed analytical procedure was validated by applying it to a certified reference soil material (CRM811-050). A recovery of 103% total endosulfan residue was obtained versus certified values.     

Clean-up techniques in the pressurized liquid extraction of abiotic environmental solid samples

Pressurized liquid extraction (PLE) uses high pressure and temperature to perform exhaustive extraction and is one of the extraction techniques widely used for determining contaminants in environmental solid samples. However, under these conditions, compounds from the matrix are also extracted. Therefore, clean-up strategies must be often applied to remove interferences and avoid matrix effect in the subsequent determination. There are different clean-up strategies that can be used in PLE, some of which are applied during the extraction procedure and some are applied to the PLE extract. The aim of this review is to critically discuss these clean-up techniques used in PLE of abiotic environmental solid samples in the last 10 years. We provide the readers with information about the weaknesses and strengths of each strategy so they can select the most suitable clean-up technique for a specific environmental analytical problem.     

Large volume sample stacking in capillary zone electrophoresis for the monitoring of the degradation products of metribuzin in environmental samples

A capillary zone electrophoresis (CZE) method with UV-vis detection has been developed for the simultaneous monitoring of the major degradation products of metribuzin, i.e. deaminometribuzin (DA), deaminodiketometribuzin (DADK) and diketometribuzin (DK). The dissociation acid constants have also been estimated by CE and no significant differences have been observed with the values obtained by applying other techniques. Optimum separation has been achieved in less than 9 min in 40 mM sodium tetraborate buffer, pH 9.5 by applying a voltage of 15kV at 25 degrees C and using p-aminobenzoic acid as internal standard. In order to increase sensitivity, large volume sample stacking (LVSS) with polarity switching has been applied as on-line pre-concentration methodology. Detection limits of 10, 10 and 20 ng/mL for DA, DADK and DK, respectively were obtained. The method has been applied to soil samples, after pressurized liquid extraction (PLE). Samples were extracted at high temperature (103 degrees C and 1500 psi) using methanol as extraction solvent and sodium sulphate as drying agent. This PLE procedure was followed by an off-line pre-concentration and sample clean-up procedure by solid-phase extraction (SPE) using a LiChrolut EN sorbent column. These last two procedures were also suitable for the direct treatment of groundwater samples before CE analysis. The combination of both off-line and on-line pre-concentration procedures provided a significant improvement in sensitivity. LVSS provided pre-concentration factors of 4, 36 and 28 for DK, DA and DADK, respectively and with SPE a pre-concentration of 500-fold for the case of water samples and of 2.5-fold in the case of soil samples was obtained. The method is suitable for the monitoring of these residues in environmental samples with high sensitivity, precision and satisfactory recoveries.     

Automated trace level determination of glyphosate and aminomethyl phosphonic acid in water by on-line anion-exchange solid-phase extraction followed by cation-exchange liquid chromatography and post-column derivatization.

An automated method based on the on-line coupling of anion-exchange solid-phase extraction (SPE) and cation-exchange liquid chromatography followed by post-column derivatization and fluorescence detection has been developed for the trace level determination of glyphosate and its primary conversion product aminomethyl phosphonic acid (AMPA) in water. PRP-X100 poly(styrene-divinylbenzene)-trimethylammonium anion-exchange cartridges (20 x 2 mm, 10 microm) were selected for the SPE of glyphosate and AMPA. The ionic compounds present in the samples strongly influenced the extraction of both analytes; however, when an on-line ion-exchange clean-up step was introduced before sample SPE, the problem was largely solved. By processing 100-ml samples detection limits better than 0.02 microg/l for glyphosate and 0.1 microg/l for AMPA were achieved in river water. Both analytes were unstable in solution and the approach of storing samples on the PRP-X100 SPE cartridges was evaluated for a period of 1 month under three different storage conditions (deep freeze, refrigeration and 20 degrees C).     

Miniaturised pressurised liquid extraction of polycyclic aromatic hydrocarbons from soil and sediment with subsequent large-volume injection-gas chromatography

Analyte extraction is the main limitation when developing at-line, or on-line, procedures for the preparation of (semi)solid environmental samples. Pressurised liquid extraction (PLE) is an analyte- and matrix-independent technique which provides cleaner extracts than the time-consuming classical procedures. In the study, the practicality of miniaturised PLE performed in a stainless-steel cell, and combined with subsequent large-volume injection (LVI)-GC-MS was studied. As an example, the new system was applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in soils and a sediment. Variables affecting the PLE efficiency, such as pressure and temperature of the extraction solvent and total solvent volume, were studied. Toluene was selected as extraction solvent and a total solvent volume of 100 microl was used for the 10 min static-dynamic PLE of 50-mg samples. Additional clean-up or filtration of the sample extracts was not required. Detection limits using LVI-GC-MS were below 9 ng/g soil for the 13 PAHs more volatile than indeno[1,2,3-cd]pyrene in real soil samples and the repeatability of the complete PLE plus LVI-GC-MS method for the analysis of the endogenous PAH was better than 15%. Comparison of PLE and Soxhlet or liquid-partitioning extraction results for the analysis of non-spiked samples showed that the efficiency of PLE is the same or better than for the other two extraction methods assayed.     

Sensitive determination of herbicides in food samples by nonaqueous CE using pressurized liquid extraction

We have developed a method involving extraction with mixtures of solvents under pressure (pressurized liquid extraction (PLE)) for the determination of triazine herbicides in a series of samples from the food industry. The organic extracts obtained were subjected to a clean-up step with SPE, using Oasis MCX sorbents, after which they were analyzed by NACE. Potato was chosen as a representative matrix of horticultural products since it has a high water content. Spiked potato samples were used to optimize extraction conditions. In order to compare the results obtained with NACE, different studies were also conducted using HPLC. The detection limits in NACE were similar to those found with HPLC and were of the order of 10-15 microg/kg, depending on the analyte. Satisfactory results were obtained on applying the method proposed for the potato matrix (PLE with separation by electrophoresis) to other food matrices such as other tubercles, fruits, vegetables and cereals.     

Simultaneous extraction and determination of anionic surfactants in waters and sediments

A new method has been developed for the simultaneous determination of the most frequently used anionic surfactants - linear alkylbenzene sulfonates (LAS), alkyl ethoxysulfates (AES) and alkyl sulfates (AS) - in aqueous and sediment samples. Preconcentration and purification of water samples are carried out by means of solid-phase extraction (SPE). The efficiency of two different extraction methods for the analysis of sediments - Soxhlet extraction and pressurized liquid extraction (PLE) - has been compared. Identification and quantification of the target compounds is performed using a liquid chromatography - mass spectrometry (LC-MS) system equipped with an electrospray interface (ESI) in negative ion-mode. Homologue recoveries are 85-123% for SPE, 94-112% for Soxhlet extraction and 81-125% for PLE in the case of LAS, and 60-94% for SPE, 61-109% for Soxhlet extraction and 55-99% for PLE in the case of AES, whereas the limits of detection are 0.1-0.5 ngml(-1) in water and 1-5 ngg(-1) in sediment. This method has been applied to the determination of anionic surfactants in the Guadalete estuary (SW Spain), and LAS concentration levels from 538 to 1014 ngg(-1) in sediments and from 25.1 to 64.4 ngml(-1) in waters have been found. AES values from 168 to 536 ngg(-1) in sediments and from 4.5 to 11.9 ngml(-1) in waters are reported for the first time in European rivers.     

Advances in sample preparation in electromigration, chromatographic and mass spectrometric separation methods

The quality of sample preparation is a key factor in determining the success of analysis. While analysis of pharmaceutically important compounds in biological matrixes has driven forward the development of sample clean-up procedures in last 20 years, today's chemists face an additional challenge: sample preparation and analysis of complex biochemical samples for characterization of genotypic or phenotypic information contained in DNA and proteins. This review focuses on various sample pretreatment methods designed to meet the requirements for the analysis of biopolymers and small drugs in complex matrices. We discuss the advances in development of solid-phase extraction (SPE) sorbents, on-line SPE, membrane-based sample preparation, and sample clean-up of biopolymers prior to their analysis by mass spectrometry.     

Extractability of dioxins from soil: II. Effects of acid or alkaline pretreatment on the extractability of dioxin homologues from soil samples

The effects of sample pretreatment on the extractability of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (CoPCBs) from three suburban soil samples were evaluated. The samples were treated with 0.1?M HCl or 0.1?M NaOH and extracted by pressurized liquid extraction (PLE) with toluene. In addition, untreated soil samples were subjected to PLE with acetone. The extractability values were compared to values obtained by toluene extraction without pretreatment. Alkaline pretreatment increased the extractability of higher-chlorinated CDDs (HiCDDs), whereas acid pretreatment slightly decreased their extractability. No change in extractability was observed for higher-chlorinated CDFs under any conditions. The extractability of lower-chlorinated CDD/Fs (LoCDD/Fs) and CoPCBs was increased only by acetone extraction. PCDD/F homologue profiles in soil humic acid fractions and those in dead leaves, a major raw material of soil humus, were also determined. These results suggest that the variations in the extractability of dioxin homologues are due mainly to variations in their physical state in the soil, especially their interactions with soil humus.     

Determination of endocrine-disrupting compounds in cereals by pressurized liquid extraction and liquid chromatography-mass spectrometry. Study of background contamination

A sensitive method based on pressurized liquid extraction (PLE) and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) has been developed for the determination in cereal samples of seven endocrine-disrupting compounds: bisphenol A (BPA), 4-tert-butylbenzoic acid (BBA), 4-nonylphenol (NP), 4-tert-butylphenol (t-BP), 2,4-dichlorophenol (DCP), 2,4,5-trichlorophenol (TCP) and pentachlorophenol (PCP). For the PLE procedure, methanol was selected as the extraction solvent. An experimental design approach was applied to optimize other PLE parameters. The recoveries achieved for the all seven compounds were in the 81-104% range, with relative standard deviations of 4-9%. An additional preconcentration step, based on solid-phase extraction (SPE), after the PLE step proved to be a successful way for obtaining a more sensitive method. The detection limits achieved in corn breakfast cereals were in the 0.003-0.013 microg g(-1) range, except for BPA, with a detection limit of 0.043 microg g(-1), for a sample size of 2.5 g. These values are similar to or even lower than currently legislated limits for pesticides in cereals and cereal-based foodstuffs. We also investigated possible contamination during the experimental process by the target compounds released from purified water, plastics, syringes, peristaltic pump tubes, glassware and other laboratory materials in contact with the samples along the analytical process.     

Development of an analytical procedure for quantifying the underivatized neurotoxin β-N-methylamino-l-alanine in brain tissues

The cyanotoxin β-methylamino-l-alanine (BMAA) has received renewed attention as an environmental risk factor for sporadic cases of amyotrophic lateral sclerosis (ALS) (Nunn et al., Brain Res 410:375–379, 1987). The aim of the present study was to develop and to validate an analytical procedure that allows the quantification of native BMAA and of its natural isomer, 2,4 diaminobutyric acid (DAB), in brain tissues. An analytical procedure was previously reported by our group for the determination of underivatized BMAA in environmental samples. It included a step of sample clean-up by solid phase extraction (SPE) with a mixed-mode sorbent and the analyses were performed by LC/MS-MS using hydrophilic interaction chromatography and multiple reactions monitoring scan mode. As brain tissues have a higher lipid content, the crucial step of sample clean-up had been optimized by evaluating the efficiency of the addition of a liquid/liquid extraction step prior to the SPE procedure or alternatively, of washing steps to the SPE extraction procedure. The efficiency was checked by visualizing the complexity of the resulting chromatograms in LC/MS and their performance by using spiked brain samples. The optimized analytical procedure, including a washing step with cyclohexane to the SPE with a recovery yield close to 100 %, was validated using the total error approach and allowed the quantification of BMAA in a concentration level ranging from 20 to 1,500 ng/g in brain samples. Finally, the feasibility of implementation of this procedure was verified in human brain samples from two patients who died of ALS.     

Determination of chlormequat and mepiquat in pear,tomato, and wheat flour using on-line solid-phase extraction (Prospekt) coupled with liquid chromatography-electrospray ionization tandem mass spectrometry

A new methodology based on pressurized liquid extraction (PLE) followed by LC-MS is presented for the simultaneous and unequivocal determination of alkylphenol ethoxylates (APEOs) and their degradation products, alkylphenols (APs) and alkylphenoxy carboxylates (APECs), in sediment samples. The protocol, applicable to a full range of APEO oligomers and degradation products, permits the sensitive and selective determination of APEOs (nEO = 1-15), APECs (nEO = 0-1) and APs at low ppb levels (LODs = 1-5 microg/kg) in sediment samples. Optimization of the operational parameters of PLE clearly demonstrates that significant thermal losses of APs occur during extraction at elevated temperatures. The loss of octylphenol (OP) at 100 degrees C was 61.2% and of nonylphenol (NP) 40.0%, whereas other compounds were completely recovered. Thus, to avoid losses due to the volatility of alkylphenols, a low extraction temperature should be applied. The conditions that gave the best results for all target compounds were as follows: extraction solvent mixture, methanol-acetone (1:1, v/v); temperature, 50 degrees C; pressure, 1500 p.s.i.; two static cycles. Using PLE and a subsequent clean-up with solid-phase extraction (SPE), the simultaneous extraction of APEOs, APs and APECs from sediment samples was achieved yielding recoveries >70% and producing low MS background noise. The developed methodology was applied on a routine basis to the analysis of alkylphenolic compounds in sediment samples. APEOs and their persistent degradation products were detected in significant concentrations in sediments from Portuguese rivers, especially at sites situated in the proximity of industrial plants (mainly the textile industry). The total concentration of alkylphenolic compounds (APEOs+APs+APECs) ranged from 155 to 2400 microg/kg. Of all the alkylphenolic compounds, NP comprised 40 to 50% with concentrations up to 1172 microg/kg.     

Closed-loop stripping analysis of synthetic musk compounds from fish tissues with measurement by gas chromatography-mass spectrometry with selected-ion monitoring

Synthetic musk compounds have been found in surface water, fish tissues, and human breast milk. Current techniques for separating these compounds from fish tissues require tedious sample clean-up procedures. A simple method for the determination of synthetic musk compounds in fish tissues has been developed. Closed-loop stripping of saponified fish tissues in a 1-1 Wheaton purge-and-trap vessel is used to strip compounds with high vapor pressures such as synthetic musks from the matrix onto a solid sorbent (Abselut Nexus). This technique is useful for screening biological tissues that contain lipids for musk compounds. Analytes are desorbed from the sorbent trap sequentially with polar and nonpolar solvents, concentrated, and directly analyzed by high resolution gas chromatography coupled to a mass spectrometer operating in the selected ion monitoring mode. In this paper, we analyzed two homogenized samples of whole fish tissues with spiked synthetic musk compounds using closed-loop stripping analysis and pressurized liquid extraction (PLE). The analytes were not recovered quantitatively but the extraction yield was sufficiently reproducible for at least semi-quantitative purposes (screening). The method was less expensive to implement and required significantly less sample preparation than the PLE technique.