Department of Civil, Architecture and Environmental Engineering, Missouri University of Science and Technology, 207 Butler Carlton Hall, 1401 N. Pine St., Rolla, MO 65401, USA.
Talanta. 2010 Oct 15;82(5):1884-91. doi: 10.1016/j.talanta.2010.08.004. Epub 2010 Aug 12.
Dynamic gas sampling using solid phase microextraction (SPME) was evaluated for recovery of reactive terpenes and terpenoids in the presence of ozone. For limonene, α-terpineol and dihydromyrcenol in the 20-60 ppb range, this method achieves >80% recovery for ozone mixing ratios up to 100 ppb. Both the experimental results and a model analysis indicate that higher ozone concentrations and longer sampling times result in lower percent recovery. Typically greater than 90% recovery and ppb level method detection limits were achieved with a 5 min sample time. Increasing the flow rate from 100 to 400 sccm flow (5-20 cms(-1)) through the active sampler did not significantly affect sensitivity or recovery in most cases, probably due to negligible mass-transfer improvements. The recovery for each compound improves when sampling from a mixture of different species than that from a single compound sample. This may be due to competition for ozone amongst adsorbed species. Dynamic SPME sampling can improve detection and quantification of terpenes in reactive environments, especially for low vapor pressure (<5 mm Hg at 25°C) compounds that can be adsorbed to ozone scrubbers used in other methods.
采用固相微萃取（SPME）的动态气体采样方法，评估了其在臭氧存在下对反应性萜烯和萜类化合物的回收效果。对于浓度范围在 20-60 ppb 的柠檬烯、α-松油醇和二氢月桂烯醇，该方法在臭氧混合比高达 100 ppb 时，回收率超过 80%。实验结果和模型分析均表明，臭氧浓度越高，采样时间越长，回收率越低。通常情况下，采用 5 分钟的采样时间，即可实现大于 90%的回收率和 ppb 级别的方法检测限。在大多数情况下，将流量从 100 sccm 增加到 400 sccm（5-20 cm s(-1))）不会显著影响灵敏度或回收率，这可能是由于传质改进可忽略不计。与从单一化合物样品相比，从不同物种的混合物中采样时，每种化合物的回收率都会提高。这可能是由于吸附物种之间对臭氧的竞争。动态 SPME 采样可以提高反应性环境中萜烯的检测和定量水平，特别是对于那些蒸气压较低（在 25°C 时低于 5 mmHg）的化合物，这些化合物可以被其他方法中使用的臭氧洗涤器吸附。
