Commercial Solid-phase Extraction Cartridges Research Articles

For the occurrence of PPCPs from source to tap: A novel approach modified in terms of sample preservation and SPE cartridge to monitor PPCPs in our water supply

BackgroundThe ongoing infusion of pharmaceutical and personal care products (PPCPs) into ecosystems sustains a perpetual life cycle and leads to multi-generational exposures. Limited understanding of their environmental impact and their intrinsic ability to induce physiological effect in humans, even at low doses, pose great risks to human health. Few scholarly works have conducted systematic research into the occurrence of PPCPs within potable water systems. Concurrently, the associated monitoring techniques have not been comprehensively examined with regards to the specific nature of drinking water, namely whether the significant presence of disinfectants may influence the detection of PPCPs. ResultsA modified approach in terms of detailed investigation of sample preservation and optimization of an in-lab fabricated solid phase extraction (SPE) cartridge filled with DVB-VP and PS-DVB sorbent was proposed. Favorable methodological parameters were achieved, with correlation coefficients spanning from 0.9866 to 0.9998. The LODs of the PPCPs fluctuated from 0.001 to 2 μg L−1, while the LOQs varied from 0.002 to 5 μg L−1. The analysis of spiked samples disclosed a methodological precision of 2.31–9.86 % and a recovery of 52.4–119 %. We utilized the established method for analyzing 14 water samples of three categories (source water, finished water and tap water) from five centralized water supply plants. A total of 24 categories encompassing 72 PPCPs were detected, with the concentrations of PPCPs manifested a marked decrease from source water to finished water and finally to tap water. SignificanceOur research meticulously examined the enhancement and purification effects of widely used commercial SPE cartridges and suggested the use of in-lab fabricated SPE cartridges packed with DVB-VP and PS-DVB adsorbents. We also conducted a systematic evaluation of the need to incorporate ascorbic acid and sodium thiosulfate as preservatives for PPCP measurement, in consideration of the unique characteristics of drinking water matrices, specifically, the significant concentration levels of disinfectants. Furthermore, the proposed method was effectively employed to study the presence of PPCPs in source water, finished water, and tap water collected from centralized water supply plants.

Preparation of chemically modified cellulose filter paper for extracting amphetamine-type stimulants from water followed by HPLC-MS/MS determination

A novel chemically modified cellulose filter paper (CMCFP) was prepared by a two-step reaction of esterification and thiol-ene click reaction with cellulose filter paper (CFP). The paper based CMCFP extraction material was used to extract amphetamine-type stimulants (ATSs) from water, followed by high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-MS/MS) determination. The FT-IR, XPS, and SEM characterizations showed that the modifiers of 3-mercaptopropionic acid and sodium 4-vinylbenzenesulfonate were successfully covalently grafted onto the CFP. The recovery rates of the 7 target ATSs by CMCFP extraction had a maximum value in the pH range of 4.0–7.0. The kinetic experiments indicated that the main adsorption mechanism of CMCFP for ATSs was chemisorption. The adsorption capacity was greater than 37 ng·cm-2. Surface water and wastewater spike experiments revealed that the determination of 7 ATSs by CMCFP extraction coupled with HPLC-MS/MS method had recoveries of 80.5–116%. Meanwhile, the detection limits were 0.40–3.03 ng·L-1, and the linear range was 20–1000 ng·L-1 with relative standard deviations of 2.2–11%. The CMCFP extraction material obtained in this study is environmentally friendly and economical, and has the same good extraction efficiency as the commercial solid phase extraction cartridges.

Sugarcane bagasse as low-cost solid-phase extraction sorbent for pesticides in water

Effective recycling of organic residues contributes to solving energy crisis and resource recycling. In Egypt, sugarcane is considered one of the most produced agricultural product, which in terms leads to the production of a vast amount of its by-products. In this work, for the first time, untreated sugarcane bagasse (SCB) was utilised as a sorbent in the solid-phase extraction (SPE) of selected pesticides including chlorfenvinphos, chlorpyrifos, diazinon, ethion, profenofos (organophosphorus compounds) and cyprodinil (anilinopyrimidine) from water. Optimal parameters influencing the recovery of the studied pesticides including eluting solvent (type, volume and pH), amount of sorbent and water pH were adjusted. Method performance criteria using SCB cartridges were compared with that of commercial SPE cartridges, indicating SCB as an effective and green chemistry alternative. The final SPE procedure can be briefly described as follows: the SCB (500 mg) SPE cartridge was conditioned with 5 mL methanol followed by 5 mL distilled water. Then, 500 mL water sample (DIW) was loaded on the SCB SPE cartridge. Afterwards, the cartridge was dried using nitrogen for 15 min. Then, 4 mL acetonitrile containing 5% formic acid was used as the eluting solvent to be analysed using LC-MS/MS. The method was validated in accordance with (SANTE/2020/12830 and Eurachem Second Edition 2014). Rapid adsorption and desorption performance for SCB was confirmed by using adsorption kinetic and isotherm studies. Finally, five environmental water samples were analysed using the developed method, only one sample had positive result (profenofos 0.01 µg/L), which is below the accepted limits.

Porous electrospun microfibers for low flow-resistant solid phase extraction of fluoroquinolones in tap water, egg and milk samples

In this work, porous electrospun microfibers (PEMFs) were prepared using a polyimide/polyvinylpyrrolidone/polyethylene glycol (PI/PVP/PEG) solution mixture with coaxial ultrasonic water vapor spraying. After removing PVP and PEG by ultrasonic water washing, the PEMFs were successfully demonstrated as adsorbents for solid phase extraction (SPE). Most non-porous electrospun nanofibers are hundreds of nanometers in diameter, with a specific surface area of dozens of square meters per gram. In contrast, the diameter of the as-prepared PEMFs was tuned between 3 and 8μm, the specific surface area was 76 m2g-1 and the pore size was ca 25nm. Therefore, the flow resistance of the PEMF-SPE cartridges was similar to those of conventional commercial SPE cartridges, and much lower than those of SPE cartridges packed with electrospun nanofibers. Using the PEMF-SPE cartridges with ultra-performance liquid chromatography-fluorescence detector (UPLC-FLD), five fluoroquinolones (FQs) in tap water, egg and milk samples were extracted and quantified successfully. After optimizing the extraction conditions, FQs in water samples were extracted and eluted with high recoveries of 84.8-114.8%. The inter-batch and intra-batch relative standard deviation (RSD) values for the FQs were in the range of 1.9-9.5% (n=3), and the limits of detection were between 0.0024-0.014μg L-1. The method was linear in the concentration range of 0.005-10μg L-1. The reliability of the developed method was validated by analyzing tap water, egg and milk samples, and the recovery values were found to be in the range of 74.8-116.6% under the optimized conditions.

Surface modification of coconut shell activated carbon for efficient solid-phase extraction of N-nitrosodimethylamine from water.

A practical and cheap methodology in modifying commercial coconut shell activated carbon for solid-phase extraction of N-nitrosodimethylamine in water was developed through an understanding of activated carbon surface chemistry. In comparison with commercial activated carbon, extraction recoveries by activated carbon treated with sulfuric acid decreased by 50%, while those of activated carbon heated at 800°C improved by more than 100%. Acid treatment increased the oxygen content on the carbon's surface. In contrast, heat treatment decreased the surface oxygen content, resulting in a more hydrophobic surface, which favoured adsorption and extraction of N-nitrosodimethylamine. The influence of different activated carbon sizes, amount of modified activated carbon, and pH on the N-nitrosodimethylamine recoveries was assessed and compared with the commercial solid-phase extraction cartridge. The recommended amount of powder activated carbon treated at 800°C was 3g to yield an optimum recovery of 130%, which was superior to the commercial solid-phase extraction cartridges. The method validation results confirmed the high accuracy, reproducibility, and precision of the method. The study indicated that chemisorption plays a significant role in the adsorption of N-nitrosodimethylamine on activated carbon, and the optimization of its surface chemistry can enhance N-nitrosodimethylamine adsorption/extraction from water.

Effect of flow rate and freezing on cyanocobalamin recovery using a commercial solid phase extraction cartridge

Analysis of vitamin B₁₂ in sea water is laborious, time consuming, and often requires storage of relatively large-volume water samples. Alleviating these major limitations will increase the throughput of samples and, as a consequence, improve our understanding of the distribution and role of vitamin B₁₂ in the oceans.

Development of a solid-phase extraction method with simple MEKC-UV analysis for simultaneous detection of indole metabolites in human urine after administration of indole dietary supplement

This work presents the development of a solid phase extraction method with simple MEKC-UV analysis for the simultaneous determination of indole-3-carbinol (I3C) and its metabolites (3, 3′-diindolylmethane (DIM), indole-3-carboxaldehyde (I3CAL), indole-3-acetonitrile (I3A)) in human urine after oral administration of an indole dietary supplement. Solid phase extraction (SPE) method was applied for the first time for simultaneous analysis of these indole metabolites. The MEKC separation method was developed in a previous work. Three commercial SPE cartridges, each with different sorbent materials, were investigated: Sep-Pak® C18, Oasis® HLB and Oasis® WCX. The Sep-Pak® C18 material provided the highest extraction recovery of 88–113% (n = 9), for the four target indole metabolites (I3C, DIM, I3CAL and I3A). The optimal washing and elution solutions were 40% methanol/water (v/v) and 100% methanol, respectively, and optimal elution volume was 2.0mL. The specificity of the proposed SPE method was evaluated with negative control urine samples (n = 10) from healthy volunteers who had not taken the dietary supplement or vegetables known to contain indole compounds. Linear calibration curves were in the range of 0.2–25μgmL−1 (r2 > 0.998) using diphenylamine (DPA) as the internal standard. Intra-day and inter-day precisions were 3.5–12.3%RSD and 2.7–14.1%RSD, respectively. Limits of detection and quantification were 0.05–0.10μgmL−1 and 0.10–0.50μgmL−1, respectively. The four target indole compounds were separated within only 5min by MEKC-UV analysis. Urine from 5 subjects who had taken a dietary supplement containing I3C and DIM were found to contain only the DIM metabolite at concentrations ranging from 0.10 to 0.35µgmL−1. Accuracy of the proposed method based on the percentage recovery of spiked urine samples were 70–108%, 82–116%, 82–132% and 80–100% for I3C, I3CAL, I3A and DIM, respectively. The Sep-Pak®C18 cartridge was highly effective in extraction and sample cleanup for the downstream simultaneous detection of urinary indole metabolites by MEKC-UV method.

Synthesis and evaluation of a molecularly imprinted polymer for selective adsorption and quantification of Acid Green 16 textile dye in water samples

An alternative for determining environmental pollutants, like textile dyes, is the use of molecularly imprinted polymers (MIPs) as solid phase extraction (SPE) or as sensor recognition systems. MIPs are tailor-made artificial receptor sites in a polymer, which present good affinity and selectivity. This work shows the synthesis of MIPs for the Acid Green 16 (AG16) textile dye and the results of rebinding, selectivity and application of this MIP in water samples. MIP synthesis was performed using AG16 dye (template), 1-vinylimidazole (functional monomer), ethylene-glycol-dimethacrylate (cross-link), 2,2′-azobis(2-methylpropionitrile) (initiator) and methanol (solvent) by bulk synthesis. The imprinted polymer presented excellent rebinding of 83%, an imprinted factor of 6.91 and great selectivity in comparison with other textile dyes. Additionally, the MIP showed high efficiency in the extraction of this dye in water samples, presenting a recovery rate close to 100% and a better performance when compared to commercial SPE cartridges. Due to this excellent performance for AG16, the application of this MIP to determine dyes in different matrices of environmental importance is promising.

Determination of Tetracyclines in Milk by Graphene-Based Solid-Phase Extraction and High-Performance Liquid Chromatography

ABSTRACTA graphene-based solid-phase extraction (SPE) column was prepared for the isolation of tetracyclines from milk followed by determination by high-performance liquid chromatography. Graphene provided better separation for tetracyclines than amine-modified graphene and carboxyl-modified graphene. The optimized graphene-based SPE column showed high absorption capacities (greater than 4,660 ng) and high recoveries (exceeding 92%) for tetracycline, oxytetracycline, chlortetracycline, and doxycycline and was successfully reused at least fifty times. The limits of detection in milk were from 10 to 20 ng/mL, with recoveries between 82.3 and 103.6%. Furthermore, the system showed superior performance than two commercial SPE cartridges with respect to recovery, purification, and reusability. Therefore, this approach is suitable for the determination of tetracyclines in milk.

Evaluation of Molecularly Imprinted Polymers for the Simultaneous SPE of Six Corticosteroids in Milk

A molecularly imprinted solid-phase extraction procedure was optimized for the simultaneous extraction of six corticosteroids commonly employed in animal husbandry. Two different molecularly imprinted polymers (MIPs) were synthetized by precipitation polymerization, using dexamethasone (DM) and flumethasone (FLU) as template molecules. Methacrylic acid was used as functional monomer and divinylbenzene as cross-linker, and the selected porogen was a solution of acetonitrile and toluene (3:1). After removal of the template, both molecularly imprinted and non-imprinted polymers were placed into glass cartridges to perform solid-phase extraction experiments. Loading, washing and elution steps were optimized for each MIP in order to test the suitability of the selected template molecules DM and FLU to provide selective polymeric sites for corticosteroids. Recovery measurements were performed by HPLC–MS/MS. The maximum recovery for all corticosteroids was achieved with DM-based MIP when loading with toluene and washing with 5% acetonitrile in toluene, and eluting with 1% acetic acid in methanol. When cleaning-up milk samples spiked with corticosteroids, the recovery of DM-based polymer decreased. However, the efficiency of FLU-based polymer clearly improved even when a strong matrix effect was observed. Additionally, two frequently used commercial solid-phase extraction (SPE) cartridges were compared with imprinted polymers. The commercial SPE cartridges gave good recoveries only for specific analytes while MIPs provided good recoveries for all analyzed corticosteroids.

Simple preparation and purification of ethanol-free solutions of 3′-deoxy-3′-[18F]fluorothymidine by means of disposable solid-phase extraction cartridges

3'-Deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) shows great potential as a tracer for proliferative studies with PET. However, its regular application is often limited by low radiochemical yields and the use of a troublesome HPLC separation. Moreover, a high content of ethanol, at least one-fold higher than the European Pharmacopoeia and US Pharmacopoeia's established limit, is always present in the final product. The present study reports an optimization of the reaction conditions and a simple and straightforward purification step which affords a solution of [(18)F]FLT suitable for human use. Several conditions and materials were tested for both the nucleophilic substitution and purification step. The latter was achieved by means of a series of commercial solid-phase extraction cartridges. Very conveniently, the whole one-pot synthesis was carried out on commercial automated modules using basically the same setup employed for the synthesis of [(18)F]FDG. Under routine conditions, radiochemical yields of 37% [decay-corrected to start of synthesis (SOS)] were achieved in ca. 39 min from SOS, with radiochemical purities >98% (usually >99%). The negligible radiolysis observed could be easily suppressed by adding 0.5% of EtOH. Typical unlabelled chemical impurities detected were thymidine (0.15 ppm), thymine (0.28 ppm) and stavudine (0.05 ppm). A reliable, simple and efficient preparation of [(18)F]FLT has been developed, able to afford an ethanol-free solution of the tracer with no need for any HPLC purification. Because of its similarity to the [(18)F]FDG synthesis, the method can be readily implemented on basically all the commercial modules developed for this common radiotracer.

Selective enrichment of the degradation products of organophosphorus nerve agents by zirconia based solid-phase extraction

Selective extraction and enrichment of nerve agent degradation products has been achieved using zirconia based commercial solid-phase extraction cartridges. Target analytes were O-alkyl alkylphosphonic acids and alkylphosphonic acids, the environmental markers of nerve agents such as sarin, soman and VX. Critical extraction parameters such as modifier concentration, nature and volume of washing and eluting solvents were investigated. Amongst other anionic compounds, selectivity in extraction was observed for organophosphorus compounds. Recoveries of analytes were determined by GC–MS which ranged from 80% to 115%. Comparison of zirconia based solid-phase extraction method with anion-exchange solid-phase extraction revealed its selectivity towards phosphonic acids. The limits of detection (LOD) and limit of quantification (LOQ) with selected analytes were achieved down to 4.3 and 8.5 ng mL −1, respectively, in selected ion monitoring mode.

An analytical method for the simultaneous trace determination of acidic pharmaceuticals and phenolic endocrine disrupting chemicals in wastewater and sewage sludge by gas chromatography-mass spectrometry

This article presents an analytical method based on solid-phase extraction (SPE) and gas chromatography coupled with mass spectrometry for the simultaneous determination of the most frequently used acidic pharmaceutical residues, ibuprofen, diclofenac, naproxen and ketoprofen (KFN), and phenolic endocrine disruptors, bisphenol (BPA), triclosan (TCS), nonylphenol, nonylphenol monoethoxylate and nonylphenol diethoxylate, in wastewater and sewage sludge samples. In the first phase of the study, each compound has been characterized individually and afterwards in mixture as a trimethylsilyl derivative in order to identify the characteristic ions (m/z ratio) constituting the mass spectrum and to choose the ions for quantification and confirmation. Subsequently, derivatization was evaluated by testing different variables such as the volume of the derivatization solvent bis(trimethylsilyl)trifluoroacetamide and the effect of each catalyst, pyridine and 1% trimethyl chlorosilane, in the derivatized solution. For the analysis of wastewater samples, two commercial SPE cartridges, C18 and Oasis HLB, were compared for their extraction efficiency of the target compounds. The key parameter of extraction procedure included the effect of pH (2.5, 5.3 and 7) of the loading solution. For solid samples, parameters such as the extracted biomass, the volume of the extraction organic solvent and the effect of matrix interferences in chromatographic analysis were evaluated. By using C18 cartridges as purification procedure and ultrasound sonication, satisfactory mean relative recoveries with BPA-d16 and meclofenamic acid as surrogates were obtained ranging from 91% to 117% for wastewater and 84% to 107% for sewage sludge samples. Nine-point calibration of the standard mixture was performed by linear regression analysis with a correlation coefficient >0.99 for all the tested compounds. Limits of detection for the developed methods were established between 0.3 (KFN) and 14.8 (BPA) ng L(-1), and 15.0 (TCS) and 32.9 (BPA) ng g(-1) for wastewater and sewage sludge, respectively. Application to real samples of the wastewater treatment plant in Athens, the capital of Greece, demonstrated the presence of all tested compounds in most of the samples.

Determination of decamethylcyclopentasiloxane in air using commercial solid phase extraction cartridges

Decamethylcyclopentasiloxane (D 5), a high production volume chemical used in personal care products, has been designated for regulation in Canada and is under review in the EU because of concerns about its persistence and potential for bioaccumulation in the environment. D 5 is a volatile compound expected to be found primarily in air, but there is little information on atmospheric concentrations due to the lack of sensitive analytical methods. Here a simple and sensitive method to determine D 5 in ambient air is presented. The challenge in the environmental analysis of D 5 is avoiding contamination. Our method is based on the high trapping efficiency of the sorbent Isolute ENV+, combined with a comparably high sampling rate. A small amount of sorbent (10 mg) is eluted in a small volume of n-hexane (0.1–0.6 mL), which is injected onto a GC/MS system without further processing. The simplicity of the method enables the use of a field blank for every sample to trace contamination. The method provides low limits of quantification (∼0.3 ng/m 3), good repeatability and limited breakthrough (∼1%). By lowering the limit of quantification compared to published work by almost two orders of magnitude, it became possible to quantify D 5 in ambient air at locations remote from strong point sources. The concentrations at a rural Swedish site ranged from 0.7 to 8 ng/m 3 over a period of 4 months.

Evaluation of carbon nanocones/disks as sorbent material for solid-phase extraction

The potential of carbon nanocones/disks as sorbent material in solid-phase extraction (SPE) procedures has been evaluated. For this aim, a model analytical problem, the determination of chlorophenols in water samples, was selected. An accurately weighed amount of 20 mg of purified carbon nanocones/disks was packed in 3 mL commercial SPE cartridges. Once conditioned, up to 8 mL of water samples can be preconcentrated without analyte losses. The chlorophenols were eluted by using 200 μL of hexane. Aliquots of 2 μL of the organic extract were injected in the gas chromatograph–mass spectrometer for separation and quantification. The purification of the commercial nanocones/disks to reduce the presence of amorphous carbon has been successfully achieved by heating the carbon nanocones/disks at 450 °C for 20 min. Detection limits of chlorophenols were in the range 0.3–8 ng mL −1 by using 2 mL of sample. Moreover, excellent average recovery values (98.8–100.9%) have been obtained after the analysis of water samples from different nature. Finally, the performance of the carbon nanocones/disks as sorbent material has been compared with that of multiwalled carbon nanotubes, providing the former better results under the experimental conditions assayed.

Development and application of a method for the analysis of N-acylhomoserine lactones by solid-phase extraction and ultra high pressure liquid chromatography

A robust method based on solid-phase extraction (SPE) followed by ultra high pressure liquid chromatography (with trade name of Ultra Performance Liquid Chromatography: UPLC; Waters, Milford, MA, USA) is proposed for the determination of five derivatives of N-acylhomoserine lactones (AHLs) that play a biological role as signal molecules of several gram-negative bacteria. Different commercial SPE cartridges were tested for sample extraction, clean-up and preconcentration. Since the sample matrix was a complex growth media, careful optimization of the SPE with respect to washing procedure, elution solvent and sample solvent was necessary. No sample loss was observed when up to 100 mL spiked full media was added onto the cartridge. Applying UPLC for the determination of AHLs, the performance characteristics of the method showed good separation efficiency and high speed. In order to demonstrate the applicability of the method, supernatants with the known AHL producer Burkholderia cepacia LA3 grown in different media were investigated. Additionally, the method was successfully used for the degradation/uptake study of AHLs from a liquid matrix in which barley was grown under controlled condition.

Supercritical fluid extraction and clean-up of organochlorine pesticides in ginseng

A method involving the simultaneous extraction and clean-up of nine organochlorine pesticides (OCPs) from the actual ginseng was developed using supercritical fluid extraction (SFE) and off-line solid-phase extraction (SPE) cartridge. The pesticides in the study consisted of α-, β-, γ- and δ-benzene hexachloride (BHC), pentchloronitrobenzene and DDT and its metabolites. The target analytes extracted were collected with an off-line commercial solid-phase extraction cartridge, recovered with eluting solvent and quantified by gas chromatography-electron-capture detection together with mass spectrometric confirmation. The optimal extraction conditions was obtained from a series of experiments in which samples preloaded by 10 wt.% ethanol–H 2O solutions, 300 bar extraction pressure, 60 °C extraction temperature, with C 18 as trap adsorbent and n-hexane as eluting solvent. Additionally, Soxhlet extraction of organochlorine pesticides in actual ginseng was also carried out. Experimental results showed that SFE was more rapid and more effective than Soxhlet extraction.

Comparison of different commercial solid-phase extraction cartridges used to extract heterocyclic amines from a lyophilised meat extract

Heterocyclic amines are a group of potent mutagenic compounds which are generated when muscle meat is cooked. Since they are possible human carcinogens, these mutagens have received considerable attention in recent years, and several analytical techniques have been developed for their quantification. Although the purification step is one of the most important, there are a great number of variables influencing the recovery of the amines, especially when real samples are analysed. In this work we studied the influence of sample spiking mode on the recoveries. Furthermore, on the basis of a previously developed clean-up method, the effect of changing commercial source and structure of the sorbents used in two solid-phase extraction steps was examined. This purification method was applied to the quantification of the heterocyclic aromatic amines present in a lyophilised meat extract by means of liquid chromatography–mass spectrometry.

Validation and robustness testing of a HPLC method for the determination of avermectins and moxidectin in animal liver samples using an alumina column clean-up.

A multi-residue method has been developed for the quantitative determination of moxidectin, abamectin, doramectin and ivermectin in liver samples, with capability for qualitative identification of the presence of eprinomectin. Liver samples are extracted with isooctane, followed by clean-up on alumina-N solid phase extraction (SPE) cartridges. Extracts are derivatised and determined by high-performance liquid chromatography (HPLC) with fluorescence detection. The method was validated using bovine liver fortified at levels of 4 and 20 micrograms kg-1 with the drugs. The mean recovery from bovine liver ranged between 90 and 96%. The intra and inter-assay variations showed RSD typically of < 5% and < 10%, respectively. The procedure was applied also to ovine and porcine liver, giving similar results. A robustness study, carried out on the alumina clean-up step, indicated that the step is relatively insensitive to method changes. However, significant differences overall were found for the type of alumina and/or commercial SPE cartridge used. The limit of quantitation of the method is 2 micrograms kg-1 (ppb).

Multiresidue recovery at PPB levels of 10 nitrosamines from frankfurters by supercritical fluid extraction.

The design of a laboratory-assembled supercritical fluid extractor is described for the efficient recovery of volatile nitrosamines from a common-cured meat product, frankfurters. The principal feature of the apparatus was a newly designed restrictor-collector interface where a commercial solid-phase extraction cartridge was directly attached to the micrometering valve. This reduced the path length between the discharge tube and the 1 g silica gel sorbent bed. The elapsed time for each 2.5 g sample extraction with supercritical CO2 was 17 min. The nitrosamines were separated and detected using a gas-chromatographic chemiluminescence (Thermal Energy Analyzer, Thermedics, Inc.; Woburn, MA) system. Recovery of 10 volatile aliphatic and alicyclic nitrosamines from frankfurters, fortified at the 20 ppb level, ranged from 84.3 to 104.8% with relative standard deviation of 2.34 to 6.13%.