Automated Solid-phase Extraction Research Articles

Determination of nine pesticide residues in honey using high performance liquid chromatography-tandem mass spectrometry

A method is proposed for the simultaneous determination of nine benzimidazole and neonicotinoid pesticides present in honey by employing automatic solid-phase extraction with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A honey sample was dissolved in a phosphate buffer (pH=7.8) followed by ultrasonic extraction. The extracts were then purified through solid-phase extraction (SPE) with hydrophilic-lipophilic balance (HLB) cartridges. Finally, nitrogen was blown on the obtained mixture, and the mixture was subsequently filtered for conducting HPLC-MS/MS analysis. Nine compounds were detected under the multiple reaction monitoring (MRM) mode, and the corresponding quantification was performed by employing the method of internal standards. The nine detected pesticides demonstrated good linearity in the range of 0.002-0.05 mg/L, with the correlation coefficient values (r2) being higher than 0.99. The limits of detection (LODs) (S/N=3) and limits of quantification (LOQs) (S/N=10) were found to be in the ranges of 0.1-1.0 μg/kg and 0.3-2.0 μg/kg, respectively. Furthermore, the results indicated that the recoveries of the nine detected pesticides range from 78.2%-101.2% at three spiked levels of 5.0, 10.0, and 20.0 μg/kg with a relative standard deviation (RSD) range of 1.3%-14.3% (n=6). Hence, the proposed method is rapid and can be employed for accurate determination of pesticide residues in large quantities of honey samples.

Development and application of gas chromatographymass spectrometry method for quantitive determination of volatile N-nitrosamines in smoked meat products

The article presents the results of experimental studies on the development of highly sensitive and selective chromatography-mass spectrometry technique for the determination of 9 N-nitrosamines in food samples (sausage products) using distillation and an automatic solid-phase extraction system on Coconut cartridges for sample preparation. In the elaborated conditions of sample preparation (distillation and solid-phase extraction) and chromatography-mass spectrometric analysis, we achieved a high recovery and efficiency of the separation of nine N-nitrosamines. The quantitation limit was at level of 0.0002 mg/kg with maximum error not exceeding 19%. The complex use of the distillation of N-nitrosamines with the addition of potassium hydroxide in combination with the optimal elution scheme for solid-phase extraction and concentrating the distillate into a Coconut carbon cartridge of 6 ml ensures the recovery of N-nitrosamines from the food product sample (sausage products) up to 93.2-100%. The process of approbation of the chromatography-mass spectrometric method in the samples of food products (sausage products) of various manufacturers revealed the content of N-nitrosamines in the concentration range 0.00029±0.000055÷0.350±0.05 mg/kg. The conducted studies of the content of the sum of highly toxic N-nitrosamines (N-nitrosodimethylamine, N-nitrosodiethylamine) made it possible to disclose that in sample No. 5 the maximum allowable concentration was exceeded by 47 times, in samples No. 2 and 16, to 57.5 and 22.9 times and in sample No. 4 to 88 times, respectively.

Complexing porous polymer monoliths for online solid-phase extraction of metals in sequential injection analysis with electrochemical detection

A monolithic column affording complexing groups was synthesized for automated solid-phase extraction of potentially toxic metal ions in a low-pressure sequential injection analyzer. Poly(glycidyl methacrylate-co-ethylene dimethacrylate) monoliths were synthesized by free-radical polymerization in the coffins of fused silica-lined stainless-steel tubes (2.10 mm i.d. × 5–6 cm length). High permeability (4.33 × 10–13 m2) was achieved for monoliths polymerized for 24 h at 60 °C from a mixture of 30 wt% glycidyl methacrylate, 10 wt% ethylene glycol dimethacrylate, 35 wt% n-propanol, 20 wt% 1,4 butanediol and 5 wt% water. Azobisisobutyronitrile (1 wt% with respect to the monomers) initiated the free-radical polymerization. These generic columns were modified with iminodiacetate to create complexing functionalities on the polymer surface, being further used for online solid-phase extraction of Cu2+, Pb2+ and Cd2+ from natural, tap and drinking waters prior to their determination by stripping chronopotentiometry. The high permeability of the column allowed the loading, washing, eluting and reconditioning steps to be made at flow rate of 10 µL s–1. The limits of detection and quantification achieved by processing 1500 µL of sample were 0.51 and 1.7 µg L–1 for Cu2+, 1.4 and 4.7 µg L–1 for Pb2+, and 1.2 and 3.8 µg L–1 for Cd2+, respectively. Recoveries were between 75.5% and 117%, obtained by quantification via external calibration curves, thus eliminating the need for the laborious standard addition strategies.

METHODOLOGICAL SUPPORT OF CONTROL OF THE CONTENT OF N-NITROZODIPHENYLAMINE IN FOOD MEAT AND MEAT/PLANT PRODUCTS

The methodical methods used in the practice of the development and application of methods for the determination of chemical compounds in food products for practical instrumental studies used in conducting laboratory studies of food safety are considered. An algorithm for the development of a chromatography-mass spectrometric technique for the determination of one of the group of highly toxic, carcinogenic N-nitrosamines (N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosopyrrolidineamin, N-nitrosomorpholinamine, N-nitrosodipropylamine, N- nitrosopiperidinamine N-nitrosoperidineamine and N-nitrosodiphenylamine in homogenized canned meat and meat products (canned meat) is supposed. The algorithm included experimental development of chromium parameters of chromatography-mass spectrometric determination of an analyte, the selection of optimum conditions of sample preparation of samples of canned meat to minimize the influence of the matrix: the transesterification reaction of fatty acids, organic solvent extraction, solid phase extraction, study of extraction completeness by means of the method “introduced - found”, establishment of metrological characteristics of the process of the measurement. The high sensitivity and selectivity of the chromatography-mass spectrometric determination of N-nitrosodiphenylamine in canned meat samples with a lower limit of 0.0002 mg/kg and a maximum error of not more than 23% was achieved owing to the use of a set of methodical techniques - the selection of optimal chromatographic analysis conditions: capillary column series HP-FFAP 50m • 0,320 mm • 0,50 μm, temperature programming of the column: initial temperature of 50ºС, the temperature rise up to 120ºС at a speed of 8ºC/min; from 120º to 185° C at a rate of 12° C min and from 185º to 240° C at a rate of 25°C/min with exposition at a final temperature of 5 minutes; mode of operation of the mass spectrometric detector: selective ion monitoring (SIM) for three characteristic ions of the analyzed compound of 167, 168, 169 m/z. Using the reaction of transesterification of fatty acids contained in canned meat, potassium methylate, removal of the formed esters from samples of canned meat with an organic solvent (hexane), concentration of N-nitrosodiphenylamine in the aqueous layer on cartridges of an automatic solid-phase extraction system provides the extraction of N-nitrosodiphenylamine from the test samples by 99.94%. In the process of approbation of the chromatography-mass spectrometric method, the content of N-nitrosodiphenylamine in the concentration range 0.030 ± 0.011 ÷ 3.89 ± 0.83 mg/kg was found in samples of homogenized canned food meat and meat products (canned meat) from various manufacturers. The highest concentration of N-nitrosodiphenylamine C = 3.89 ± 0.83 mg/kg was found in the sample of canned meat «beef + chicken».

Automatic solid-phase extraction by programmable flow injection coupled to chromatographic fluorimetric determination of fluoroquinolones

Automatic sample preparation targeting preconcentration of fluoroquinolones present in environmental waters.

Determination of polycyclic aromatic hydrocarbons in environmental waters from southern Spain by using a continuous solid-phase extraction system and gas chromatography-mass spectrometry

Environmental contextPolycyclic aromatic hydrocarbons are widespread carcinogenic compounds resulting from incomplete combustion of fossil fuels. We report a robust analytical method suitable for detecting these compounds at trace levels in various types of environmental waters. The method allows for accurate monitoring of the levels and behaviour of these priority environmental pollutants. AbstractHuman exposure to polycyclic aromatic hydrocarbons (PAHs) is a major challenge for the scientific community. The European Commission and the European Food Safety Agency have declared PAHs as priority pollutants, and sanctioned their quantification and monitoring in water and foods, owing to their carcinogenic, teratogenic, and mutagenic properties. We report a method for determining sixteen PAHs in various types of environmental water samples collected from various sources and places in the south of Spain. The target compounds were preconcentrated to a reduced volume (350 µL) with an automatic solid-phase extraction system and determined by gas chromatography–mass spectrometry. Optimising the operational variables, such as the type and nature of sorbent, and analytical variables resulted in a very low limit of detection (0.01–0.3 ng L−1), high accuracy and precision (RSD < 7.5 %), and recoveries of 86–102 % from 200 mL of sample. The method was applied to a variety of environmental water samples, many of which were found to contain PAHs at different levels, depending on the nature and origin the sample. In any case, such levels were lower than the maximum tolerated limits except for sea and waste water. In the case of waste water, a comparison between influent and effluent from the waste water treatment plant was performed to assess the effect over the environment after their treatment, where a reduction of the presence of PAHs in the samples was observed.

Fast trace determination of nine odorant and estrogenic chloro- and bromo-phenolic compounds in real water samples through automated solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

A fast and reliable method was developed for simultaneous trace determination of nine odorous and estrogenic chloro- and bromo-phenolic compounds (CPs and BPs) in water samples using solid-phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). For sample preparation, the extraction efficiencies of two widely applied cartridges Oasis HLB and Sep-Pak C18 were compared, and the Oasis HLB cartridge showed much better extraction performance; pH of water sample also plays important role on extraction, and pH = 2-3 was found to be most appropriate. For separation of the target compounds, small addition of ammonium hydroxide can obviously improve the detection sensitivity, and the optimized addition concentration was determined as 0.2%. The developed efficient method was validated and showed excellent linearity (R 2 > 0.995), low limit of detection (LOD, 1.9-6.2ng/L), and good recovery efficiencies of 57-95% in surface and tap water with low relative standard deviation (RSD, 1.3-17.4%). The developed method was finally applied to one tap and one surface water samples and most of these nine targets were detected, but all of them were below their odor thresholds, and their estrogen equivalent (EEQ) were also very low.

Determination of N-nitrosodiphenylamine in meat canned food for children by the method of chromato-massspectrometry

This study demonstrates the results obtained from the GC/MS experimental determination of low concentrations of N-nitrosodiphenylamine in meat canned baby food in the concentration range of 0.027-3.89 mg/kg. The perfect conditions of sample preparation (extraction with organic solvent and solid phase extraction) as well as the application of the chromatography-mass spectrometry allowed us to detect N-nitrosodiphenylamine in samples of the meat canned baby food with high selectivity in concentrations ranged from 0.016 to 5 mg/kg when an error of 23% was assumed. The use of the reaction of transesterification of fatty acids by potassium methylate, the removal of the ester generated from the samples of canned meat by organic solvent (hexane), concentrating of N-nitrosodiphenylamine in the aqueous layer on the cartridges of an automatic solid-phase extraction system provided 99.94% extraction of N-nitrosodiphenylamine from the canned meat samples. The experiment has made evident the presence of N-nitrosodiphenylamine in the samples of canned meat (beef + chicken) with the help of mass-spectrometry method in the mode of full ion scanning using the AMDIS automatic mass-spectral identification system.

Automated microfluidic devices integrating solid-phase extraction, fluorescent labeling, and microchip electrophoresis for preterm birth biomarker analysis.

We have developed multichannel integrated microfluidic devices for automated preconcentration, labeling, purification, and separation of preterm birth (PTB) biomarkers. We fabricated multilayer poly(dimethylsiloxane)-cyclic olefin copolymer (PDMS-COC) devices that perform solid-phase extraction (SPE) and microchip electrophoresis (μCE) for automated PTB biomarker analysis. The PDMS control layer had a peristaltic pump and pneumatic valves for flow control, while the PDMS fluidic layer had five input reservoirs connected to microchannels and a μCE system. The COC layers had a reversed-phase octyl methacrylate porous polymer monolith for SPE and fluorescent labeling of PTB biomarkers. We determined μCE conditions for two PTB biomarkers, ferritin (Fer) and corticotropin-releasing factor (CRF). We used these integrated microfluidic devices to preconcentrate and purify off-chip-labeled Fer and CRF in an automated fashion. Finally, we performed a fully automated on-chip analysis of unlabeled PTB biomarkers, involving SPE, labeling, and μCE separation with 1h total analysis time. These integrated systems have strong potential to be combined with upstream immunoaffinity extraction, offering a compact sample-to-answer biomarker analysis platform. Graphical abstract Pressure-actuated integrated microfluidic devices have been developed for automated solid-phase extraction, fluorescent labeling, and microchip electrophoresis of preterm birth biomarkers.

3D printed device including disk-based solid-phase extraction for the automated speciation of iron using the multisyringe flow injection analysis technique

The development of advanced manufacturing techniques is crucial for the design of novel analytical tools with unprecedented features. Advanced manufacturing, also known as 3D printing, has been explored for the first time to fabricate modular devices with integrated features for disk-based automated solid-phase extraction (SPE). A modular device integrating analyte oxidation, disk-based SPE and analyte complexation has been fabricated using stereolithographic 3D printing. The 3D printed device is directly connected to flow-based analytical instrumentation, replacing typical flow networks based on discrete elements. As proof of concept, the 3D printed device was implemented in a multisyringe flow injection analysis (MSFIA) system, and applied to the fully automated speciation, SPE and spectrophotometric quantification of Fe in water samples. The obtained limit of detection for total Fe determination was 7ng, with a dynamic linear range from 22ng to 2400ng Fe (3mL sample). An intra-day RSD of 4% (n = 12) and an inter-day RSD of 4.3% (n = 5, 3mL sample, different day with a different disk), were obtained. Incorporation of integrated 3D printed devices with automated flow-based techniques showed improved sensitivity (85% increase on the measured peak height for the determination of total Fe) in comparison with analogous flow manifolds built from conventional tubing and connectors. Our work represents a step forward towards the improved reproducibility in the fabrication of manifolds for flow-based automated methods of analysis, which is especially relevant in the implementation of interlaboratory analysis.

Quantitative determination of AVI-7100 (Radavirsen), a phosphorodiamidate morpholino oligomer (PMOplus® ), in human plasma using LC-MS/MS.

AVI-7100 (Radavirsen) is a 20-mer phosphorodiamidate morpholino oligomer (PMOplus®) for the treatment of influenza. Results/methodology: An automated solid-phase extraction method was used to extract plasma samples (200 μl). The extracts were analyzed using liquid chromatography coupled with tandem mass spectrometry under the positive ionization mode. This method was fully validated over the calibration curve range of 5.00-1000 ng/ml. The between-run precision and accuracy ranged from 0.0 to 5.2% relative standard deviation and 91.6 to 100.0% of nominal for all quality control concentrations, including the lower limit of quantitation. This is the first liquid chromatography coupled with tandem mass spectrometry method for the measurement of AVI-7100 concentrations in human plasma. It has been used to support regulated bioanalysis.

An ultra-high-pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the detection of cannabinoids in whole blood using solid phase extraction

ABSTRACTA novel high-throughput method using automated solid-phase extraction (SPE) coupled with ultra-high-pressure liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) was developed in order to quantify Δ9-tetrahydrocannabinol (THC) and its major metabolites and screen for several synthetic cannabinoids. Cannabinoids and synthetic cannabinoids were extracted from ovine whole blood using Phenomenex Strata-X Drug B SPE columns. Multiple reaction monitoring (MRM) mode was used to monitor at least two transitions of the analyte and its deuterated internal standard. Calibration was fitted quadratically (R2 > 0.995) over a range from 1 to 20 ng/mL for THC, 11-hydroxy-THC, cannabinol and cannabidiol, and 10 to 200 ng/mL for 11-nor-Δ9-carboxy-tetrahydrocannabinol and its glucuronide. Inter-assay accuracy and precision were evaluated over n = 3 analyses spanning six days. With the exception of cannabidiol, the accuracies ranged from 0.52% to 8.63% and the coefficient of variation (%CV) was found to range from 1.91% to 7.69%. Intra-assay accuracy and the precision of these analytes (n = 16) was found to range from 0.16% to 11.42% and from 1.10% to 8.40%, respectively. Cannabidiol intra- and inter-assay accuracy and precision were more variable than for other analytes. The procedure minimized specimen handling, extraction and reduced runtime as compared with an existing gas chromatography–mass spectrometry method and permitted the qualitative identification of several synthetic cannabinoid species.

RapidFire Mass Spectrometry with Enhanced Throughput as an Alternative to Liquid-Liquid Salt Assisted Extraction and LC/MS Analysis for Sulfonamides in Honey.

The use of veterinary drugs in honey bees for the prevention of infectious disease is ever increasing due to the spread of colony collapse disorder around the world. The United States Food and Drug Administration is concerned about the presence of these drugs residues in honey as they often lead to health concerns or potential antibiotic resistance. Currently there is a need for a rapid screening method for the detection of veterinary drugs in honey. Herein is a method that utilizes automated solid-phase extraction that is directly coupled to a mass spectrometer for the quantitative screening of 12 different regulated sulfonamides in honey. Identification of the residues was performed using tandem mass spectrometry (MS/MS) with a triple quadrupole mass spectrometer. The acquisition method developed for this analysis can extract with the automated solid-phase extraction system and analyze a single sample on the mass spectrometer in approximately 20 s, with minimal sample preparation. A target testing limit of 10 ng/g in honey for the sulfonamides was used based upon action limits set for other food commodities regulated by the United States Food and Drug Administration. A complete method validation procedure was conducted to evaluate the effectiveness of this quantitative screening method.

Metal-organic framework mixed-matrix disks: Versatile supports for automated solid-phase extraction prior to chromatographic separation

We present for the first time the application of metal-organic framework (MOF) mixed-matrix disks (MMD) for the automated flow-through solid-phase extraction (SPE) of environmental pollutants. Zirconium terephthalate UiO-66 and UiO-66-NH2 MOFs with different size (90, 200 and 300nm) have been incorporated into mechanically stable polyvinylidene difluoride (PVDF) disks. The performance of the MOF-MMDs for automated SPE of seven substituted phenols prior to HPLC analysis has been evaluated using the sequential injection analysis technique. MOF-MMDs enabled the simultaneous extraction of phenols with the concomitant size exclusion of molecules of larger size. The best extraction performance was obtained using a MOF-MMD containing 90nm UiO-66-NH2 crystals. Using the selected MOF-MMD, detection limits ranging from 0.1 to 0.2μgL−1 were obtained. Relative standard deviations ranged from 3.9 to 5.3% intra-day, and 4.7–5.7% inter-day. Membrane batch-to-batch reproducibility was from 5.2 to 6.4%. Three different groundwater samples were analyzed with the proposed method using MOF-MMDs, obtaining recoveries ranging from 90 to 98% for all tested analytes.

Residue depletion of ivermectin in broiler poultry

ABSTRACTHelminth infections are widespread in the poultry industry. There is evidence of extra-label use of some drugs, such as ivermectin (IVM), in broiler poultry. Pharmacokinetic and residual studies of IVM in poultry, however, are rather scarce. Our aim was to determine time restrictions for broiler chickens fed with balanced feed mixed with IVM for 21 days, and thus achieve acceptable residual levels for consumption as established by the European Union. Sixty 1-day-old chicks were fed with food supplemented with IVM at 5 mg kg–1 feed for 21 days. Groups of six treated animals were sacrificed at 0, 1, 2, 4, 8, 10, 15, 20 and 28 days after treatment. Liver, skin/fat, kidney and muscle samples were obtained. IVM were determined by liquid chromatography with fluorescence detection after automatic solid-phase extraction with SPE C18 cartridges. The highest concentrations were measured in the liver, which is logical given that IVM is a drug that undergoes extensive hepatic metabolism. The optimal withdrawal time for edible tissues of these animals to stay within the permitted residual levels were: 12 days for liver, 8 days for skin/fat, 0 days for muscle and 10 days for kidney.

Automatic solid phase extraction of cadmium exploiting a multicommutated flow system previous ICP-MS detection: Application to tobacco samples

A miniaturized automatic sample pre-treatment system, based on multicommutated flow techniques, i.e. Lab on Valve (LOV) and Multisyringe Flow Injection Analysis (MSFIA) techniques, for cadmium determination by ICP-MS in organic samples is presented. The on-line extraction and preconcentration system retains the analyte on the resin (Dowex 50W-X8), followed of elution with 1molL−1 HNO3. The LOV-MSFIA system allows the fully automation of solid phase renewal, which shown a durability of 130 injections without its replacement. The optimal operating conditions were investigated using multivariate optimization tools. The detection limit was 0.05ng of cadmium, while the mass linear working range was 0.2–100ng. The precision of the proposed methodology was 2.4% (RSD, n=10) with a sample frequency of 9 injections h−1.The accuracy of the method was established by means of an organic matrix certified reference material (DORM-2), and the method has been successfully applied to different samples of tobacco (commercial cigarettes, pipe tobacco and tobacco leaves), obtaining recoveries between 90 and 105%. Main advantages of the proposed methodology are a minimal sample handling, good precision, high stability of the column and the versatility achieved by a variety of managed sample volumes.

Submicrometric Magnetic Nanoporous Carbons Derived from Metal-Organic Frameworks Enabling Automated Electromagnet-Assisted Online Solid-Phase Extraction.

We present the first application of submicrometric magnetic nanoporous carbons (μMNPCs) as sorbents for automated solid-phase extraction (SPE). Small zeolitic imidazolate framework-67 crystals are obtained at room temperature and directly carbonized under an inert atmosphere to obtain submicrometric nanoporous carbons containing magnetic cobalt nanoparticles. The μMNPCs have a high contact area, high stability, and their preparation is simple and cost-effective. The prepared μMNPCs are exploited as sorbents in a microcolumn format in a sequential injection analysis (SIA) system with online spectrophotometric detection, which includes a specially designed three-dimensional (3D)-printed holder containing an automatically actuated electromagnet. The combined action of permanent magnets and an automatically actuated electromagnet enabled the movement of the solid bed of particles inside the microcolumn, preventing their aggregation, increasing the versatility of the system, and increasing the preconcentration efficiency. The method was optimized using a full factorial design and Doehlert Matrix. The developed system was applied to the determination of anionic surfactants, exploiting the retention of the ion-pairs formed with Methylene Blue on the μMNPC. Using sodium dodecyl sulfate as a model analyte, quantification was linear from 50 to 1000 μg L(-1), and the detection limit was equal to 17.5 μg L(-1), the coefficient of variation (n = 8; 100 μg L(-1)) was 2.7%, and the analysis throughput was 13 h(-1). The developed approach was applied to the determination of anionic surfactants in water samples (natural water, groundwater, and wastewater), yielding recoveries of 93% to 110% (95% confidence level).

Automated solid-phase extraction of organic pollutants using melamine–formaldehyde polymer-derived carbon foams

Solid-phase extraction of environmental pollutants is accomplished using carbon foams derived from melamine–formaldehyde polymer foams.

Lipidomics of tobacco leaf and cigarette smoke

Detailed lipidomics experiments were performed on the extracts of cured tobacco leaf and of cigarette smoke condensate (CSC) using high-resolution liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-Q-TOF MS). Following automated solid-phase extraction (SPE) fractionation of the lipid extracts, over 350 lipids could be annotated. From a large-scale study on 22 different leaf samples, it was determined that differentiation based on curing type was possible for both the tobacco leaf and the CSC extracts. Lipids responsible for the classification were identified and the findings were correlated to proteomics data acquired from the same tobacco leaf samples. Prediction models were constructed based on the lipid profiles observed in the 22 leaf samples and successfully allowed for curing type classification of new tobacco leaves. A comparison of the leaf and CSC data provided insight into the lipidome changes that occur during the smoking process. It was determined that lipids which survive the smoking process retain the same curing type trends in both the tobacco leaf and CSC data.

Identification and Quantification of Aromatic Hydrocarbons Adsorbed on Soot from Premixed Flames of Kerosene, Synthetic Kerosene, and Kerosene–Synthetic Biofuels

In the current study, the chemical characterization of polycyclic aromatic hydrocarbons (PAHs) adsorbed on soot from premixed flames of synthetic paraffinic kerosene (SPK), conventional kerosene (Jet A-1), and Jet A-1/synthetic biofuel blends was carried out. Jet A-1 and SPK liquid fuels were analyzed with NMR to provide supporting information on their chemical composition. The analytical procedure used to characterize PAHs fraction in soot samples includes the following: (i) filtration of the soot samples diluted into n-hexane through PTFE filters, (ii) automated solid-phase extraction (A-SPE) for fractioning and cleaning-up the soot extracts, and (iii) chromatographic analysis of every fraction by reverse high-performance liquid chromatography (RPLC) with photodiode array (PDA) detection. Application of the aforementioned methodology allowed the identification of 78 compounds including indene, toluene, and 76 PAHs. Moreover, the relative abundance of five-membered-ring PAHs and alkyl PAHs was evaluated, and 19 PAHs (16 EPA PAHs, 1-methylnaphthalene, 2-methylnaphthalene, and coronene) were quantified. The PAH characterization should contribute to improve our understanding of atmospheric reactivity of soot and other environmental aspects of aromatic compounds adsorbed on soot.