这个气体ppb浓度是怎么计算出来的?
用红外分光计测得某乙酸戊酯溶液(n-amylacetate,nAA;CAS;628-63-7;MW130.18;99%purity)挥发速度为68ng/min,加载到速度为4升每分钟(4lpm)的气流中,那么该气流中的nAA浓度为3.13ppb.
这个气流浓度是怎么算出来的?
文献原文:
Inordertocharacterizelab-madePTs,weusedanIRspectrometer(MIRANSapphIReAmbientAirAnalyzer,model205B;ThermoEnvironmentalInstrumentsInc.;Franklin,MA)inaclosedloopsystemofknownvolume.Therateofincreaseinconcentrationallowedthereleaseratetobecalculated.Forexample,onePThadareleaserateof68ng/min,whichwouldresultinaconcentrationof3.13ppbwhenthisPTwasplacedinastreamof4litresperminute(lpm).