at 400 ppm with multipath cell
12CO2 : 400 ppm +- 0.3 ppb = around 0.000075 %
13CO2 : around 4.4ppm +-0.1 ppb = 0.002 %
Delta = around 0.002 % at 400 ppm ( with 10 s integration)
Delta = around 0.001% at 400pmm (with 60 s integration)
基于光声光谱技术,直接吸收检测,测试ppb结果。比值可以一算即可。
国内很多测试机构。