Determination of volatile and semivolatile mutagens in air using solid absorbents and supercritical fluid extraction.
Determination of volatile and semivolatile mutagens in air using solid absorbents and supercritical fluid extraction.
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使用固体吸收剂和超临界流体萃取测定空气中的挥发性和半挥发性诱变剂。
DOI：
10.1021/ac00015a027
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发表时间：
1991
影响因子：
7.4
通讯作者：
Seiber,JN
中科院分区：
文献类型：
--
作者：
Wong,JM;Kado,NY;Kuzmicky,PA;Ning,HS;Woodrow,JE;Hsieh,DP;Seiber,JN
0003 - 2700/91/0363 - 1644 $02.50/0（例如Tenax）和在低温阱中收集分析物（15，16）。该技术受到分析物和吸附剂稳定性的限制，并且它也可能导致不完全回收。超临界流体萃取（SFE）的有机物吸附剂代表了一个强大的替代传统的样品制备方法。与传统的萃取方法相比，超临界流体萃取可以提供更快速、更有效的萃取，提高选择性，并具有潜在的样品分离能力。这些优点可归因于溶剂在高于其临界点的温度和压力下的性质。超临界流体表现出与液体相似的密度，但溶质扩散率和粘度更接近气体;这些特性促进溶质的传质，从而实现快速有效的提取。取决于密度的流体的溶剂强度可以通过改变压力或使用溶剂改性剂（17）来改变。此外，具有低临界温度的流体允许在相对温和的条件下进行提取，从而最大限度地减少化学变化。通常，二氧化碳的临界温度为304.2 K，临界压力为72 atm（7295 kPa），临界密度为0.468 g/mL，一直是首选流体（18）。临界点是可接近的，它是有机物的良好溶剂，并且它无毒、不易燃、便宜。几项研究表明，使用CO2的SFE可以快速定量地从土壤和植被中回收农药（19，20），从食物中回收天然产物（21），从固体基质中回收多环芳烃、多氯联苯和二恶英（22 - 26）。SFE在空气样品中的应用包括从Tenax、氧化铝和木炭中提取多环芳烃，从Tenax中提取无烟污染物和有毒有机物，从XAD-2中提取多环芳烃，以及从PUF中提取木烟流出物（13，27 - 30）。用超临界流体萃取可以对分离挥发性物质构成主要优点，因为容易从分析物中除去作为气体的萃取流体，例如CO2。不需要溶剂蒸发步骤或用于生物测定测试的交换溶剂的步骤。通过产生浓缩的提取物，分析物回收可以大大简化，潜在的样品损失可以最小化，因为提取物可以直接分析，而无需额外的样品制备。以二氯甲烷、二溴乙烯、4-硝基联苯、2-硝基芴和荧蒽为模型挥发性致突变化合物，对空气样品的采集和提取方法进行了优化。这些化合物代表不同类别的化学品，挥发物范围从349 mmHg（二氯甲烷）到0.01 mmHg（荧蒽）。测试的吸附剂包括木炭、Carbosieve Sill、XAD-4、Tenax TA和Chromosorb 102。通过使用以CO2作为溶剂的SFE研究分析物回收。在CO2挥发后，直接分析浓缩的提取物，无需额外的浓缩步骤。用二溴化乙烯和4-硝基联苯证明了捕获和解吸方法与沙门氏菌生物测定的集成。实验部分
0003-2700/91/0363-1644 $02.50/0 (eg Tenax) and collection of analytes in a cryogenic trap (15, 16). This technique is limited by analyte and adsorbent stability, and it too may result in incompleterecovery. Supercritical fluid extraction (SFE) of organics from ad-sorbents represents a powerful alternative to traditional methods of sample preparation. When compared to con-ventional extraction methods, SFE can provide a more rapid and efficient extraction, increased selectivity, and potential sample fractionation. These advantages can be attributed to properties of a solvent at temperatures and pressuresabove its critical point. Supercritical fluids exhibit densities similar to those of a liquid, yet with solute diffusivities and viscosities closer to those of a gas; these properties facilitate mass transfer of solutes resulting in a rapid and efficient extraction. The solvent strength of the fluid, which depends on density, may be varied by changes in thepressure or by using solvent modifiers (17). In addition, fluids with low critical temperatures allow extractions at relatively mild conditions, thus minimizing chemical changes. Typically, carbon dioxide, with its critical temperature of 304.2 K, critical pressure of 72 atm (7295 kPa), and critical density of 0.468 g/mL, has been a fluid of choice (18). The critical point is accessible, it is a good solvent for organics, and it is nontoxic, nonflammable, and inexpensive.Several studies have shown that SFE with C02 can yield rapid and quantitative recoveries of pesticides from soil and vegetation (19, 20), natural products from foods (21), and PAHs, PCBs, and dioxins from solid matrices (22-26). Applications of SFE for air samples include extracting PAHs from Tenax, alumina and charcoal, cigarettesmoke pollutants and toxic organics from Tenax, PAHs from XAD-2, and woodsmoke effluent from PUF (13, 27-30). Extracting with supercritical fluids can pose a major advantage for isolating volatile species, since it is easy to remove the extracting fluid, such as C02, as a gas from the analyte. There is no need for a solvent evaporation step or a step to exchange solvents for bioassay testing. By producing concentrated extracts, analyte recovery can be drastically simplified and potential sample loss can be minimized, since the extracts can be directly an-alyzed without additional sample preparation. In the present study, the model volatile mutagenic com-pounds dichloromethane, ethylene dibromide, 4-nitrobiphenyl, 2-nitrofluorene, and fluoranthene were used to optimize collection and extraction methods for air samples. These compounds represented different classes of chemicals with volatiles ranging from 349 mmHg (dichloromethane) to 0.01 mmHg (fluoranthene). Adsorbents tested included charcoal, Carbosieve Sill, XAD-4, Tenax TA, and Chromosorb 102. Analyte recovery was investigated by using SFE with C02 as the solvent. Upon volatilization of the C02, concentrated extracts were analyzed directly without additional concen-tration steps. Integration of trapping and desorption methods with theSalmonella bioassay was demonstrated with ethylene dibromide and 4-nitrobiphenyl. EXPERIMENTAL SECTION