I am the responsible person for standard solutions room, I introduce the purity of the active ingridient purity in calculations, So I want to check it annualy for quality control requirements. I have HPLC-UV&flourscence GC-ECD&NPD. I need accurate method to check the purity of the active ingridients.

I guess you are trying to assay the purity of your standard which you use to assay samples. If this is the case, you may want to check the Aldrich catalog and see if they have that chemical. You may then ask their technical support for assay methodology. Good lock

In this lab we acquire standard materials of the highest purity (usually 99+%) available from different sources, compare those to each other, and then use those high grade standards for analytical standards on our GC and LC equipment. These standards are available from several sources that specialize in that type of work. Chemservice is one we use a lot.

If you are analyzing formulations, then the AOAC (Association of Official Agricultural Chemists, AOAC.org, I think--search engines should find it) methods are a good place to start. LC/UV and GC/FID are the most-used tools. Typical concentrations run on the systems are 0.5 to 1 mg/mL, which cuts instrument error to 1 or 2%. 'Samples' and standards are run in triplicate, and the results averaged. Your ECD and NPD probably won't be very useful.

It is surprising how often these materials are not what they say they are, and the only way to know is to compare them to each other.

You are obviously thinking--many people wouldn't ask the question. It can be a difficult job, but you obviously realize the importance of doing it.

Usually organic environmental standards are tested
for purity and identity: GC/FID and GC/MS rsp.

Inorganic stds, wherever possible, are assayed vs
NIST stds.

Some good sources of stds, aside from ChemService,
are Ultra Sci., Accustandard and Restek