by
Hornet » Tue May 08, 2018 9:54 am
sana70 wrote:
HI
I want to measure the detection limit of the GC-FID , which i analyse the gas samples like propane and ethylene.
please help me to measure the LOD and LOQ.
also i have just one standard mix gas( all component about 18 ppm).
thank you.
I don't use LOD, no one asks for it and to me (ISO 17025 as well) the only value that counts is LOQ.
My LOQ is always my lowest calibration point, i put it in these terms: if i can't calibrate it, i can't quantify it.
If you can calibrate it and R2 is good and avg RSD% is less than 25% i'm done.
Probably it won't be the lowest possible LOQ you can get, but as soon as it's ok for your job (for example, at least 10 times less than maximum allowed concentration for your regulatory limit) it's way more accurate than using S/N.
Just my 2 cents.