Leite Natalicio Ferreira, Peralta-Zamora Patricio, Grassi Marco Tadeu
Instituto de Tecnologia do Paraná (TECPAR), 81350-010 Curitiba, PR, Brazil.
J Chromatogr A. 2008 May 30;1192(2):273-81. doi: 10.1016/j.chroma.2008.03.067. Epub 2008 Mar 28.
A procedure for the determination of very low polycyclic aromatic hydrocarbons (PAHs) concentrations in sediment samples has been developed by gas chromatography-quadrupole ion trap mass spectrometry (GC-QIT MS) after extraction with dichloromethane and purification by using silica gel cleanup. Identification and quantification of analytes were based on the selected ion storage (SIS) strategy using deuterated PAHs as internal standards. In order to search out the main factors affecting the SIS mass spectrometry efficiency, four MS parameters, including target total ion count (TTIC), waveform amplitude (WA), transfer line (XLT) and ion trap temperatures (ITT) were subjected to a complete multifactorial design. The most relevant parameters obtained (TTIC and WA) were optimized by a rotatable and orthogonal composite design. Optimum values for these parameters were selected for the development of the method involving PAH determination in sediment samples. The optimized method exhibited a range of 111-760% higher signal-to-noise (S/N) ratios for PAHs in comparison with the method operated by the default conditions, demonstrating that the multifactorial optimization contributed to substantially improve the sensitivity of the GC-QIT MS determination. The accuracy of the method was verified by analyzing NWRI EC-3 certified reference material (Lake Ontario sediment). The selectivity, sensitivity (limits of quantification were in the range of 0.02-11.0 ng g(-1)), accuracy (recoveries >or=77%) and precision (RSD<or=30%) obtained were quite adequate for the determination of very low target PAHs in sediment samples. The established method was then applied to determine 16 PAHs in river sediments from the Metropolitan Region of Curitiba, Brazil. Two selected sediment samples were analyzed, one from the Canguiri River (a slightly urbanized area), and the other from the Iguaçu River (a heavily urbanized area), illustrating the capabilities of the method to detect PAHs at the threshold concentrations necessary to classify the sediments as well as the status of contamination.
建立了一种测定沉积物样品中极低浓度多环芳烃（PAHs）的方法。该方法采用二氯甲烷萃取，硅胶净化，然后通过气相色谱 - 四极杆离子阱质谱（GC - QIT MS）进行分析。以氘代PAHs作为内标，基于选择离子存储（SIS）策略对分析物进行定性和定量。为了找出影响SIS质谱效率的主要因素，对四个质谱参数，包括目标总离子计数（TTIC）、波形幅度（WA）、传输线（XLT）和离子阱温度（ITT）进行了完全多因素设计。通过旋转和正交复合设计对获得的最相关参数（TTIC和WA）进行优化。选择这些参数的最佳值用于开发沉积物样品中PAHs测定方法。与默认条件下运行的方法相比，优化后的方法对PAHs的信噪比（S/N）提高了111 - 760%，表明多因素优化极大地提高了GC - QIT MS测定的灵敏度。通过分析NWRI EC - 3认证参考物质（安大略湖沉积物）验证了该方法的准确性。所获得的选择性、灵敏度（定量限在0.02 - 11.0 ng g⁻¹范围内）、准确性（回收率≥77%）和精密度（相对标准偏差≤30%）足以用于测定沉积物样品中极低浓度的目标PAHs。然后将所建立的方法应用于测定巴西库里蒂巴大都市区河流沉积物中的16种PAHs。分析了两个选定的沉积物样品，一个来自坎古里河（城市化程度较低的地区），另一个来自伊瓜苏河（城市化程度较高的地区），展示了该方法在检测将沉积物分类所需的阈值浓度PAHs以及污染状况方面的能力。
