Check over some of the posts from the past few weeks there have been others with similar problems. The first question that I have on hearing of this problem is what is the quality of gas you are using for carrier, FID fuel, and air? Hydrocarbon background in any of these gasses will raise the background. Second question I have is what are you using for plumbing? Connections with tubing that has been contaminated with oil ( or not properly cleaned after manufacturing) can result in the addition of hydrocarbons to the gas stream. And regulators: the diaphram material is important. Rubber or plastic can add organic compund to the gas stream. (GC vendors typicall specify stainless steel diaphrams in regulators.)
