Seyyal Emre, Malik Abdul
Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE 205, Tampa, FL 33620-5250, USA.
Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE 205, Tampa, FL 33620-5250, USA.
Anal Chim Acta. 2017 Apr 29;964:96-111. doi: 10.1016/j.aca.2017.02.031. Epub 2017 Mar 6.
Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C) and phenethyl (PhE) ligands. Here, the ability of the PF-C ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania-based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L limit of detections (LOD) (4.2-26.3 ng L) for environmentally important analytes including polycyclic aromatic hydrocarbons, ketones and aliphatic hydrocarbons. In CME-GC experiments (n = 5), the capillary-to-capillary RSD value was ∼2.1%; such a low RSD value is indicative of excellent reproducibility of the sol-gel method used for the preparation of these CME coatings. The dual-ligand sol-gel coating provided stable performance in capillary microextraction of analytes from saline samples.
利用溶胶 - 凝胶化学原理制备了基于二氧化硅和锗酸盐的双配体表面键合溶胶 - 凝胶涂层，通过配体超疏水性和π - π相互作用的结合，在毛细管微萃取（CME）中提供了增强的性能。这些有机 - 无机杂化涂层是使用带有键合全氟十二烷基（PF - C）和苯乙基（PhE）配体的溶胶 - 凝胶前驱体制备的。在此，PF - C配体提供增强的疏水相互作用的能力与PhE部分的π - π相互作用能力有利地结合，以在CME中获得所需的吸附剂性能。通过比较基于二氧化硅和锗酸盐的溶胶 - 凝胶吸附剂的微萃取特性，探索了无机吸附剂组分对微萃取性能的影响。与基于二氧化硅的对应物相比，基于锗酸盐的双配体溶胶 - 凝胶吸附剂表现出优异的CME性能。对制备的基于二氧化硅和锗酸盐的双配体溶胶 - 凝胶吸附剂进行热重分析（TGA）表明，基于锗酸盐的吸附剂上的碳负载量更高。这可能表明在溶胶溶液中，带有有机配体的溶胶 - 凝胶活性化学物种与基于锗酸盐的溶胶 - 凝胶网络（比与基于二氧化硅的对应物）的缩合更有效。在溶胶 - 凝胶吸附剂中改变有机配体的类型和浓度，以微调对不同类分析物的萃取选择性。使用特定萃取（SE）值对制备的溶胶 - 凝胶CME吸附剂进行客观比较。PF - C含量较高的吸附剂对脂肪烃表现出显著的亲和力。与它们的单配体溶胶 - 凝胶对应物相比，双配体溶胶 - 凝胶涂层在烷基苯的萃取中表现出明显优异的CME性能，提供高达约65.0％更高的SE值。制备的溶胶 - 凝胶CME涂层对包括多环芳烃、酮类和脂肪烃在内的环境重要分析物提供了低至纳克/升的检测限（LOD）（4.2 - 26.3纳克/升）。在CME - GC实验（n = 5）中，毛细管间的相对标准偏差（RSD）值约为2.1％；如此低的RSD值表明用于制备这些CME涂层的溶胶 - 凝胶方法具有出色的重现性。双配体溶胶 - 凝胶涂层在从盐水样品中毛细管微萃取分析物时提供了稳定的性能。
