Department of Chemistry, 4000 Central Florida Blvd, University of Central Florida, Orlando, Florida 32816-2366, USA.
Analyst. 2011 Aug 21;136(16):3366-74. doi: 10.1039/c1an15309a. Epub 2011 Jul 2.
Monitoring of high-molecular weight polycyclic aromatic hydrocarbons (HMW-PAH) via simple and cost effective methods still remains a challenge. In this article, we combine solid-phase nano-extraction (SPNE) and 4.2 K laser-excited time resolved Shpol'skii spectroscopy (LETRSS) into a valuable alternative for the water analysis of dibenzo[a,l]pyrene, dibenzo[a,h]pyrene, dibenzo[a,i]pyrene and naphtho[2,3-a]pyrene. In comparison to the original SPNE procedure, the present method improves PAH recoveries and reduces extraction time from 30 to 20 min per sample. Quantitative release of HMW-PAH into the Shpol'skii matrix (n-octane) is best accomplished with a mixture of 48 μL of methanol and 2 μL of 1-pentanethiol. Their migration into the 50 μL layer of n-octane provides highly resolved spectra with distinct fluorescence lifetimes for unambiguous isomer determination. Complete analysis takes less than 30 min per sample and consumes only 100 micro-liters of organic solvents. 500 μL of water are sufficient to obtain limits of detection ranging from 16 ng L(-1) (dibenzo[a,l]pyrene) to 55 ng L(-1) (dibenzo[a,i]pyrene), relative standard deviations better than 3% and analytical recoveries above 90%. Although a straightforward comparison to chromatographic methods is not possible because of the lack of analytical figures of merit on HMW-PAH, the excellent precision of measurements, limits of detection and overall recoveries makes SPNE-LETRSS an attractive approach to water analysis of HMW-PAH.
通过简单且经济有效的方法监测高分子量多环芳烃（HMW-PAH）仍然是一个挑战。在本文中，我们将固相纳米萃取（SPNE）和 4.2 K 激光激发时间分辨的 Shpol'skii 光谱（LETRSS）结合起来，为水中二苯并[a,l]蒽、二苯并[a,h]蒽、二苯并[a,i]蒽和萘并[2,3-a]蒽的分析提供了一种有价值的替代方法。与原始 SPNE 程序相比，本方法提高了 PAH 的回收率，并将每个样品的萃取时间从 30 分钟缩短至 20 分钟。用 48 μL 甲醇和 2 μL 1-戊硫醇的混合物可以最好地将 HMW-PAH 定量释放到 Shpol'skii 基质（正辛烷）中。它们迁移到 50 μL 层的正辛烷中，提供了具有独特荧光寿命的高分辨率光谱，可用于明确异构体的确定。每个样品的完整分析时间不到 30 分钟，仅消耗 100 微升有机溶剂。500 μL 的水足以获得从 16 ng L(-1)（二苯并[a,l]蒽）到 55 ng L(-1)（二苯并[a,i]蒽）的检测限，相对标准偏差优于 3%，分析回收率高于 90%。尽管由于缺乏 HMW-PAH 的分析质量指标，无法与色谱方法进行直接比较，但测量的出色精密度、检测限和整体回收率使得 SPNE-LETRSS 成为分析水中 HMW-PAH 的一种有吸引力的方法。
