Hi all,

Recently I was promoted to a Laboratory analyst and now I can do the test using Perkin Elmer Clarus 600.

However, my supervisor has suddenly resigned and leave nobody to teach me how to use GCMS. Right now I run the phthalates test using the CPSC method CPSC-CH-C1001-09.3.

I followed the method and have been ran the test for a month.
I found the following problem,

1) At the first time I did the test, the GCMS can detect the present of phthalate (e.g DEHP). However, when I did the second test (same sample), GCMS didn't detect anything from it. Provided that I am sure there was no contamination as I did the sample preparation at the same time.

2) I always got DEHP failed in a lot of sample, and their readings are so close. I do not know if it is coincidence or not, but I seldom see products that fail in other component, is DEHP so common or is there anything I have done wrong?

3) The response is getting low since the first time I ran the test, is there anything I can do to restore it?