嗅觉实验配气方法的改进及影响因素研究

Improvement on gas sample preparation of odor test and study on influencing factors

配制气体样品是异味测试及相关研究的基础工作,配气稳定性直接影响测试结果准确度。三点比较式臭袋法使用微量进样针量取并转移液体标准物质到3 L无臭气袋的传统配气方法。对于异味阈值较小物质或样品浓度处于较低范围时,为了降低取样体积波动对配气精度和稳定性的影响。提出先将标准注入100 mL玻璃注射器,充分挥发混匀后再转移部分气体到无臭气袋的两步式配气方法。结果表明,2种配气方法的准确度不存在显著差异,但两步式配气法的配气稳定性明显优于传统方法。此外,研究还发现,常见异味物质在被注入气袋后3 min内便能完全挥发并混合均匀。除一些挥发性和吸附性极强的物质外,气袋内的异味物质气体浓度能在配好后20 min内基本保持不变。

Gas sample preparation is fundamentally important for odor tests and relative scientific research, and directly affects the precision of test results. The traditional way, triangle odor bag method, is to inject liquid standard reagents into a 3L odorless bag with micro-syringe. The fluctuation of sample volume can influence the precision and stability of sample preparation, which should be possibly reduced when preparing the odorants with low thresholds or samples at low concentration levels. In the present work, a two step preparation method was es- tablished by injecting standard reagents into a 100 mL glass syringe and then transferring part of the well volatil- ized and mixed gas into the odorless bag. The results showed no distinct difference of precisions between the two methods, but our two-step one showed better stability. At the same time, we found that ordinary odorants could completely volatilize and mix well within 3 min after being injected into odorless bags. The concentrations of o- dorants in the odorless bag kept constant in 20 min after preparation except for those with strong volatility and ad- sorptivity.