I'm triyng to analyze USP OVI impurities (CH2Cl2, CHCl3, Dioxane and Trichloroetylene) with GC-FID without head space. I'm using a 0.53 I.D. 30 m 1 um film HP-INNOWAX column with both spliless or split techniques . Standard solution, in water, contains from 8 ppm of CHCl3 to 80 ppm of dioxane.
Despite a good sensibilty, I've got a poor reproducibility of peak area, RSD% n=3 inj is between 10% to 15%.
How can I improve reproducibilty ?
Thanks a lot
By Consumer Products Guy on Friday, March 12, 2004 - 06:36 am:
Inject 0.5 ul. More than that volume of water expands to more than your liner volume. One needs to especially be aware of expansion volumes when injecting water.
By vijay on Sunday, March 14, 2004 - 11:05 pm:
1. For ovi impurities rsd should be calculated for any successive six replicates.
2. Keep your initail oven temperature above 80°C
3. liner volume problem will come with agilent gc
not with all (more than 3 mL linear volume injector port systems available)
By Anonymous on Thursday, April 22, 2004 - 08:56 am:
In quantitative GCMS analysis, which parameter is most reliable or most reproducible, is it peak area or peak height? why?