Solubility and partitioning studies with polycyclic aromatic hydrocarbons using an optimized SPME procedure

In order to determine the water solubilitiy (S _W) and octanol/water partition coefficient (K _OW) of polycyclic aromatic hydrocarbons, we have optimized the direct solid-phase microextraction (SPME) of selected compounds (fluoranthene (FLU), phenanthrene (PHE), pyrene (PYR), benz[a]anthracene (BaA), benz[a]pyrene (BaP), and coronene) from the matrices water and octanol-saturated water. By the use of a 100 μm polydimethylsiloxane fibre and magnetic stirring of the sample with glass-coated mini-impellers in combination with gas chromatography we obtained limits of determination (GC-MS) comparable to standard HPLC procedures. Only coronene could not be quantified. The determined S _W of FLU agree with reference data; for B[a]P we have obtained a 2 to 3 times higher value than described in recent literature. The obtained K _OW values are close to reference data for both single components. For a mixture of FLU, PHE, PYR, and B[a]A the measured K _OW values are 0.2–0.3 log units below tabulated values for the single components. Received: 22 July 1998 / Revised: 28 October 1998 / Accepted: 1 November 1998     

Microheterogeneity evaluation of polycyclic aromatic hydrocarbons in particulate standard reference materials

With the emergence of highly sensitive analytical techniques, the microanalysis of natural-matrix materials employing smaller sample sizes is increasingly more common, which subsequently warrants a homogeneity assessment for the individual components at the appropriate sampling level. Pressurized liquid extraction (PLE) in combination with gas chromatography/mass spectrometry (GC/MS) has been used to determine the sampling constants and evaluate the relative homogeneity of trace levels of polycyclic aromatic hydrocarbons (PAHs) for two previously certified particulate standard reference materials, SRM 1649a Urban Dust and SRM 1650b Diesel Particulate Matter, in the milligram sampling range. Fluoranthene, pyrene, benz[a]anthracene and benzo[e]pyrene within SRM 1650b Diesel Particulate Matter were deemed to be homogeneous, based on relatively small sampling constants (K _S<100 mg), whereas the larger sampling constants (K _S>100 mg) obtained for all PAHs in SRM 1649a Urban Dust suggest more material heterogeneity. The material heterogeneity of ten individual PAHs (phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene) was also described via nonlinear relationships (i.e., power law) between subsampling error S _s (%) and sample mass, which are used to predict analyte-specific minimum sample masses that result in a specific level of analytical uncertainty. Electronic supplementary material Supplementary material is available for this article at and is accessible for authorized users.     

Determination of Polycyclic Aromatic Hydrocarbons in Airborne Particulate by High Performance Liquid Chromatography

This paper presents a trisolvent ultrasonic extraction and HPLC analysis method for the determination of 11 polycyclic aromatic hydrocarbons in air particulate collected on an air filter by a commercial high volume air sampler. A reverse phase column, Vydac 201 TP, and a gradient mobile phase, acetonitrile/water, were used. The 11 PAHs, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a, h]anthracene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and coronene were completely resolved under experimental conditions. All the PAHs except coronene were monitored by fluorescence with λ_ex=270 nm, λ_em>389 nm. Coronene was monitored by UV with λ=300 nm. The methodology was evaluated by spiking SRM 1649 with a PAH standard and then going through different extraction procedures and analyzing the PAH concentrations without clean-up. An external standard method was used for quantitation. The recovery yields for fluoranthene, benz[a]anthracene, benzo[a]pyrene, benzo[ghi]perylene and indeno[l,2,3-cd]pyrene were above 90%. The detection limits of PAH with fluorescence at λ_ex=270 nm, λ_em>389 nm ranged from 5.7 pg to 69.5 pg.     

Development of negligible depletion hollow fiber membrane-protected liquid-phase microextraction for simultaneous determination of partitioning coefficients and acid dissociation constants

A new method based on negligible depletion hollow fiber-protected liquid-phase microextraction coupled with high-performance liquid chromatography (HPLC) was developed for the simultaneous determination of partitioning coefficients (K_OW) and acid dissociation constants (pK_a), by using phenol, 4-chlorophenol and 2,4-dichlorophenol as model compounds. A 37-mm length polypropylene hollow fiber membranes (600 μm inner diameter, 200 μm wall-thickness, 0.2 μm pore size, ∼70% porosity) with two-end sealed were filled with 1-octanol by ultrasonic agitation to prepare the extraction device. The extraction device was deployed in sample solutions, prepared by spiking target analytes in 1-octanol saturated aqueous solutions (500 mL), for negligible depletion extraction. After equilibrium was reached (∼5 h), the 1-octanol in the lumen of the hollow fiber membrane was collected for HPLC determination of the target analytes. As the depletion of the analytes in aqueous samples was negligible, the distribution coefficient (D_OW) could be calculated based on the measured equilibrium concentration in 1-octanol (C_O) and the initial concentration (C_W) in the aqueous sample of the target analyte (D_OW = C_O/C_W). The D_OW values measured at various pH values were nonlinearly regressed with pH to obtain the K_OW and pK_a values of a compound. Results showed that the measured values of the K_OW and pK_a of these model compounds agreed well with literature data.     

Sample preparation of sewage sludge and soil samples for the determination of polycyclic aromatic hydrocarbons based on one-pot microwave-assisted saponification and extraction

A microwave-assisted sample preparation (MASP) procedure was developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge and soil samples. The procedure involved the simultaneous microwave-assisted extraction of PAHs with n-hexane and the hydrolysis of samples with methanolic potassium hydroxide. Because of the complex nature of the samples, the extracts were submitted to further cleaning with silica and Florisil solid-phase extraction cartridges connected in series. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene, were considered in the study. Quantification limits obtained for all of these compounds (between 0.4 and 14.8 μg kg⁻¹ dry mass) were well below of the limits recommended in the USA and EU. Overall recovery values ranged from 60 to 100%, with most losses being due to evaporation in the solvent exchange stages of the procedure, although excellent extraction recoveries were obtained. Validation of the accuracy was carried out with BCR-088 (sewage sludge) and BCR-524 (contaminated industrial soil) reference materials.     

PARAFAC and MCR-ALS applied to the quantitative monitoring of the photodegradation process of polycyclic aromatic hydrocarbons using three-dimensional excitation emission fluorescent spectra: Comparative results with HPLC

Two methods were developed for the simultaneous quantitative monitoring of photodegradation process of dibenz[a,h]anthracene (DibA), benz[a]anthracene (BaA), benz[a]pyrene (BaP) and benz[k]fluorantene (BkF) using excitation-emission fluorescence spectroscopy. Parallel factor analysis (PARAFAC) and multivariate curve resolution-alternating least squares (MCR-ALS) were satisfactory applied to the data obtained during this process. The results achieved were statistically compared by means of the joint interval test of slope and intercept, with the data obtained using the reference methodology, high performance liquid chromatography (HPLC) method. There are not significant differences between the methodologies proposed and the standard one, and may be a good alternative to the traditional methods of analysis for monitoring the degradation of these pollutants.     

New Hexachalcogeno–Hypodiphosphates of the Alkali Metals: Synthesis,Crystal Structure and Vibrational Spectra of the Hexathiodiphosphate(IV) Hydrates K4[P2S6] · 4 H2O,Rb4[P2S6] · 6 H2O,and Cs4[P2S6] · 6 H2O

The new hexathiodiphosphate(IV) hydrates K₄[P₂S₆] · 4 H₂O ( 1 ), Rb₄[P₂S₆] · 6 H₂O ( 2 ), and Cs₄[P₂S₆] · 6 H₂O ( 3 ) were synthesized by soft chemistry reactions from aqueous solutions of Na₄[P₂S₆] · 6 H₂O and the corresponding heavy alkali‐metal hydroxides. Their crystal structures were determined by single crystal X‐ray diffraction. K₄[P₂S₆] · 4 H₂O ( 1 ) crystallizes in the monoclinic space group P 2₁/n with a = 803.7(1), b = 1129.2(1), c = 896.6(1) pm, β = 94.09(1)°, Z = 2. Rb₄[P₂S₆] · 6 H₂O ( 2 ) crystallizes in the monoclinic space group P 2₁/c with a = 909.4(2), b = 1276.6(2), c = 914.9(2) pm, β = 114.34(2)°, Z = 2. Cs₄[P₂S₆] · 6 H₂O ( 3 ) crystallizes in the triclinic space group with a = 742.9(2), b = 929.8(2), c = 936.8(2) pm, α = 95.65(2), β = 112.87(2), γ = 112.77(2)°, Z = 1. The structures are built up by discrete [P₂S₆]^4? anions in staggered conformation, the corresponding alkali‐metal cations and water molecules. O ··· S and O ··· O hydrogen bonds between the [P₂S₆]^4? anions and the water molecules consolidate the structures into a three‐dimensional network. The different water‐content compositions result by the corresponding alkali‐metal coordination polyhedra and by the prefered number of water molecules in their coordination sphere, respectively. The FT‐Raman and FT‐IR/FIR spectra of the title compounds have been recorded and interpreted, especially with respect to the [P₂S₆]^4? group. The thermogravimetric analysis showed that K₄[P₂S₆] · 4 H₂O converted to K₄[P₂S₆] as it was heated at 100 °C.     

Improved efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) from the National Institute of Standards and Technology (NIST) Standard Reference Material Diesel Particulate Matter (SRM 2975) using accelerated solvent extraction

The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) with molecular masses of 252, 276, 278, 300, and 302 Da from standard reference material diesel particulate matter (SRM 2975) has been investigated using accelerated solvent extraction (ASE) with dichloromethane, toluene, methanol, and mixtures of toluene and methanol. Extraction of SRM 2975 using toluene/methanol (9:1, v/v) at maximum instrumental settings (200 °C, 20.7 MPa, and five extraction cycles) with 30-min extraction times resulted in the following elevations of the measured concentration when compared with the certified and reference concentrations reported by the National Institute of Standards and Technology (NIST): benzo[b]fluoranthene, 46%; benzo[k]fluoranthene, 137%; benzo[e]pyrene, 103%; benzo[a]pyrene, 1,570%; perylene, 37%; indeno[1,2,3-cd]pyrene, 41%; benzo[ghi]perylene, 163%; and coronene, 361%. The concentrations of the following PAHs were comparable to the reference values assigned by NIST: indeno[1,2,3-cd]fluoranthene, dibenz[a,h]anthracene, and picene. The measured concentration of dibenzo[a,e]-pyrene was lower than the information value reported by the NIST. The measured concentrations of other highly carcinogenic PAHs (dibenzo[a,l]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene) in SRM 2975 are also reported. Comparison of measurements using the optimized ASE method and using similar conditions to those applied by the NIST for the assignment of PAH concentrations in SRM 2975 indicated that the higher values obtained in the present study were associated with more complete extraction of PAHs from the diesel particulate material. Re-extraction of the particulate samples demonstrated that the deuterated internal standards were more readily recovered than the native PAHs, which may explain the lower values reported by the NIST. The analytical results obtained in the study demonstrated that the efficient extraction of PAHs from SRM 2975 is a critical requirement for the accurate determination of PAHs with high molecular masses in this standard reference material and that the optimization of extraction conditions is essential to avoid underestimation of the PAH concentrations. The requirement is especially relevant to the human carcinogen benzo[a]pyrene, which is commonly used as an indicator of the carcinogenic risk presented by PAH mixtures.     

Crystal Structure and Vibrational Spectrum of Dipotassium Manganese(II) Hexathiodiphosphate(IV), K2Mn[P2S6]

K₂Mn[P₂S₆] was synthesized from the elements in sealed quartz ampoules at 1 173 K. The compound forms transparent light brown crystals, stable against air and moisture. The crystal structure (monoclinic; space group P2₁/n, No. 14; a = 6.1966(9), b = 12.133(2), c = 7.424(1) Å, β = 101.52(1)°, Z = 2; Pearson code mP22) consists of columns of face-sharing S₆ polyhedra (distorted octahedra and trigonal antiprisms) parallel to the a axis, interconnected by inserted K⁺ (CN 10; d(K? S) = 3.23–3.92 Å). The S₆ polyhedra of the columns are centered alternately by Mn (in octahedra with d?(Mn? S) = 2.647 Å) and P₂ pairs (in trigonal antiprisms) which are inclined to the a axis by 73.1°. The bond lengths in the resulting hexathiodiphosphate(IV) anions, [P₂S₆]^4?, with approximate 3 2/m–D_3d symmetry, are d(P? P) = 2.211 Å and d(P? S) = 2.018 Å. K₂Mn[P₂S₆] is isotypic to K₂Fe[P₂S₆], being the second member of this structure type. The internal modes of the observed Raman and FIR/IR spectra of K₂Mn[P₂S₆] are in accord with the factor group analysis, and the fundamentals are assigned on the basis of [P₂S₆]^4? units, taking into account the deviation of the D_3d symmetry.     

Synthetic Amebicides. VIII. 7,7′-[Iminobis(alkyleneimino) [bis[benz[c] acridines] and Congeneric 9-Aminoacridines, 12-Aminobenz[a] acridines, [2-Aminobenz[b] acridines,and 4-Aminoquinolines

Thirty-five 7,7′-(iminodialkylenediimino))bis[benz[c]acridines] (VII), 7,7′-(alkylene- and phenylenediimino)bis[benz[c]acridines] (VIII and IXa-c), [iminobis(alkyleneimino)]bis[acridines, benz[a]acridines, benz[b]acridines, and quinolines] (X, Xla-c, XII, XIII, and XIVa-c), and [alkylenebis(iminoalkyleneimino)]bis[acridines, benz[c]acridines, and quinolincs] (XVI, XVII, XVIIIa and b, and XIXa-c) were synthesized by the condensation of one equivalent of the appropriate alkylenediamine with two equivalents of the requisite chloroheterocycle in phenol. Many of the bis(aminoheterocyclic) compounds are highly active against Entamoeba histolytica in vitro and in experimental animals.     

Resolution of four k-region arene imines and mutagenicity of the optically pure aziridines

Racemic K-region imines of benz[a]anthracene, 7-methylbenz[a]anthracene, chrysene and benzo[a]pyrene ( 1–4 , respectively) have been resolved by high performance liquid chromatography on a column packed with amylose tris(3,5-dimethylphenylcarbamate) on silica gel. The absolute configuration of the resolved aziridines was assigned by comparison of their circular dichromism spectra to those of the corresponding enantiomerically pure arene oxides. The mutagenicity of the enantiomers of the arene imines was investigated using Salmonella typhimurium strains TA98 and TA100. Although all arene imines investigated were potent mutagens, quantitative and qualitative differences in the mutagenic activity were observed between enantiomers.     

Synthesis of derivatives of the new heterocyclic systems benz[f] imidazo [2,1 -a ] isoquinoline and benz [f] pyrimido [2,1 -a] isoquinoline

The synthesis of several derivatives of benz [f] imidazo [2,1 -a] isoquinoline and benz [f] pyrimido-[2,l-a]isoquinoline, both new heterocyclic structures, is described.     

Hydrogenation of arenes by the RhCl3-aliquat® 336 catalyst: Part 3. Selective reduction of polycyclic compounds

Acenaphthylene, fluorene, anthracene, phenanthrene, benz[a]anthracene, pyrene, fluoranthene, benzo[c] phenanthrene and some of their derivatives were shown to undergo partial hydrogenation in the presence of the RhCl₃-Aliquat^® 336 catalyst in a highly selective manner. Olefinic double bonds were found to be hydrogenated prior to aromatic moieties. In linear aromatic molecules, only the terminal rings are reduced. In phenanthrene the C₉-C₁₀ bond and in pyrene the C₄-C₅ linkage are the only ones to be affected. Benz [a] anthracene is converted exclusively into 7,8,9,10-tetrahydrobenz[a]anthracene. Benzo[c] phenanthrene is hydrogenated to give primarily the 5,6-dihydro derivative. Chlorine and bromine substituents were found to undergo hydrogenolysis when attached to the reacting moieties, but usually remain unaffected when located on non-reacting aromatic rings.     

An Analysis of the Bonding Properties of Benz[a]azulene by X-Ray,NMR, and Computational Studies

The X-ray crystal structures of 9-phenylbenz[a]azulene ( 4 ) and the corresponding non-benzannelated form, 4-phenylazulene ( 5 ), have been determined (cf. Fig.2). In contrast to 5 , the skeleton of which shows nearly equal C,C bond lengths (cf. Table 1), the seven-membered ring of 4 exhibits clearly alternating C,C bond lengths (cf. Table 1). This is in agreement with a strong accentuation of the heptafulvene substructure in 4 by the [a] benzannelation. The alternating bond lengths of 4 and of its parent structure 3 are also reflected in the corresponding variations of the ³J(H,H) and ¹J(¹³C,¹³C) values of these benz[a]azulenes (cf. Tables 4 and 5). Computations on the MP2/6-31G^* level as well as on the BP86/6-31G^* level for azulene ( 6 ), benz[a]azulene ( 3 ), and heptafulvene ( 7 ) are in good agreement with the experimental values (cf. Tables 6–8).     

Synthesis and structure of [Ni(dien)2]3[W4S4(CN)2]·20H2O and [Cu(dien)(Hdien)]2[W4S4(CN)12]·8H2O

[Ni(dien)₂]₃[W₄S₄(CN)₁₂]·20H₂O and [Cu(dien)(Hdien)]₂[W₄S₄(CN)₁₂]·8H₂O were obtained by evaporating water-ammonia solutions containing K₆[W₄S₄(CN)₁₂]·2H₂O·2CH₃OH, diethylene triamine, and NiCl₂·6H₂O or CuCl₂·6H₂O. The crystals of the complex compounds were obtained within 3 days. The complex compounds were characterized by IR spectroscopy and by XRD and elemental analysis. XRD data for the complex [Ni(dien)₂]₃[W₄S₄(CN)₁₂]·20H₂O are: triclinic system, , a = 14.671(2) Å, b = 16.448(3) Å, c = 19.814(3) Å, α = 67.841(3)°, β = 68.996(3)°, γ = 67.527(3)°, V = 3961.6(11) ų, Z = 2; for the complex [Cu(dien)(Hdien)]₂[W₄S₄(CN)₁₂]·8H₂O: monoclinic system, C2/c, a = 37.4290(1) Å, b = 17.7370(1) Å, c = 25.7370(2) Å, β = 105.3840(2)°, V = 16474.02(16) ų, Z = 12. Original Russian Text Copyright ? 2005 by I. V. Kalinina, D. G. Samsonenko, Z. A. Starikova, A. A. Korlyukov, J. Lipkowski, V. P. Fedin, and M. Yu. Antipin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 1, pp. 139–148, January–February, 2005.     

Interaction of pyrimethamine and sulfadiazine with ionic and neutral micelles: Electronic absorption and fluorescence studies

The binding of two antitoxoplasmosis drugs, pyrimethamine (PYR) and sulfadiazine (SDZ) to cationic cetyltrimethylammonium chloride (CTAC), anionic sodium dodecylsulfate (SDS), zwiterionic N-hexadecyl-N,N-dimethyl-2-ammonium-1-propanesulfonate (HPS) and neutral polyoxyethylene-dodecyl-ether (Brij-35^®) micelles was studied using absorption and fluorescence spectroscopic methods. The pK_a of PYR changed in the presence of charged anionic, cationic and zwiterionic micelles, indicating that interaction is influenced by the micellar charge. For SDZ, pK_a changes were lower than 1 for all micelles, suggesting the occurrence of low binding constants in addition to a reasonable influence of the micellar charge. The values of binding constants K_b, obtained from fluorescence measurements, for PYR to CTAC micelles were very low at pH 4.0, where the drug is in a complete protonated state, increasing at pH 9.0 to long-chained CTAC and HPS micelles since this factor also favors accomodation of the neutral drug in the hydrophobic compartments. For SDZ the binding constants were determined from optical absorption measurements. Low binding constants were observed to charged surfactant micelles, with influence of micellar charge. It must be stated however that those values can be underestimated due to the relatively low sensitivity of the method based on absorption measurements.     

Zweikern-Komplexe des Wolframs und Molybdäns mit zentraler {XMS2 MX}2+-Einheit (X=O,S) und S 2 2− -bzw. S 4 2− -Liganden

The synthesis and crystal structures of the compounds [PPh ₄]₂[W₂S₁₂]·0.5DMF, [PPh ₄]₂[W₂O₂S₁₀]·0.5DMF, [PPh ₄]₂[W₂S₁₀]··0.5DMF, [PPh ₄][NEt ₄][Mo₂OS₇]·CH₃CN, and [PPh ₄]₂[Mo₂O₂S₁₀] are reported.

     

Synthesis,crystal structure,magnetism and vibrational spectrum of Dipotassium Iron(II) Hexathiodiphosphate(IV), K2Fe[P2S6]

K₂Fe[P₂S₆] was synthesized from the elements at 1173 K in sealed quartz tubes. The compound forms transparent orange crystals, stable against air and moisture. K₂Fe[P₂S₆] crystallizes in the monoclinic system, space group P2₁/n (No. 14), with cell dimensions (T = 298.5 K) a = 6.0622(4), b = 12.172(1) and c = 7.3787(8) Å, β = 101.113(7)°, Z = 2. The novel structure type (mP22) is characterized by columns of alternating face-sharing S₆ octahedra and trigonal antiprisms (both distorted) parallel to the a axis, which are interconnected by inserted K⁺ (CN 10; {2,6,2}-polyhedra; d(K? S) = 3.231 ? 3.845 Å). The S₆ polyhedra of the columns are centered alternately by Fe (d?(Fe? S) = 2.577 Å) and P₂ pairs which are inclined to the a axis by 73.4°. The bond lengths in the hexathiodiphosphate(IV) anions, [P₂S₆]^4?, with approximate 3 2/m – D_3d symmetry, are d?(P? P) = 2.20 and d?(P? S) = 2.02 Å. The compound is paramagnetic above T_N = 28 K with μ = 4.69 B.M. and orders antiferromagnetically below T_N. The internal modes of the observed Raman and FIR spectra of K₂Fe[P₂S₆] are in accord with the factor group analysis, and the spectra are assigned on the basis of [P₂S₆]^4? units, taking into account the deviation from D_3d symmetry.     

Thermal Reaction of Azulenes with Dimethyl Acetylenedicarboxylate in Supercritical Carbon Dioxide

1,3,4,6,8-Pentamethylazulene ( 9 ), when heated at 100° in supercritical CO₂ at 150 bar in the presence of 4 equiv. of dimethyl acetylenedicarboxylate (ADM), led to the formation of 16% of a 1:1 mixture of dimethyl 3,5,6,8,10-pentamethylheptalene-1,2-dicarboxylate 12a ) and its double-bond-shifted isomer 12b as well as 4% of the corresponding azulene-1,2-dicarboxylate 13 (Scheme 4). The formation of the [1 + 2] adduct 11 (cf. Scheme 2) was not observed. Similarly, benz[a]azulene ( 25 ) yielded in supercritical CO₂ (150°/170 bar) in the presence of 4 equiv. of ADM dimethyl benzo[d]heptalene-6,7-dicarboxylate ( 29 ; 30%) and dimethyl benzo[a]cyclopent[cd]azulene-1,2-dicarboxylate ( 28 ; 22%; Scheme 5). The reaction of 5,9-diphenylbenz[a]azulene ( 26 ) and ADM in supercritical CO₂ (100°/150 bar) gave the corresponding benzo[d]heptalene-6,7-dicarboxylate 31 (22%) and dimethyl 5,9-diphenyl-4b,10-etheno-10H-benz[a]azulene-11,12-dicarboxylate( 30 ; 25%; Scheme 5).     

Detection of Benzo[a]pyrene in Fried Food by Ultrasound-Assisted Matrix Solid-Phase Dispersion and Isotope Dilution GC–MS

A simple, sensitive and reliable analytical method was developed for the detection of benzo[a]pyrene in fried food using gas chromatography-mass spectrometry with an isotope-labelled internal standard. Samples were directly extracted and purified by the ultrasound-assisted matrix solid-phase dispersion (MSPD) procedure. The simple pretreatment procedures were tested with different absorbents (C18, NH₂, Oasis, and SiO₂). The optimal ultrasonication-assisted MSPD was achieved by MSPD-SiO₂ and sonication for 10 min in an ultrasonic bath. The samples were quantified using benzo[a]pyrene-d₁₂ as the internal standard. An analysis of the samples spiked with different levels of benzo[a]pyrene showed recoveries ranging from 84.6 to 103.2 %, with an RSD of 3.21–8.32 %, depending on the spiking level. This method was thus shown to be suitable for the detection of benzo[a]pyrene in fried food.