How to quantify salivary cortisol accurately

[Mountain]

I need to purchase the equipment and learn how to use it to monitor salivary cortisol and catechols as accurately as a medical lab. Any suggestions to get me started?

[HW Mueller]

Are you talking about a clinical chemistry lab? You would then probably want to do RIA or ELISA (immunoassays). For the catecholamines you may even adopt a HPLC kit from Chromsystems.
I still think that most of these are estimates rather than analyses. See for instance J Chrom B, 678, 137 (1996) for problems involved with cortisol determonation in plasma.

[Mountain]

Yes, I'm talking about a clinical lab. For cortisol I believe HPLC is much more accurate than RIA, right? All assays will be done with salivary biomarkers.

But I don't really have any idea what equipment will be needed or how to get started. I would prefer something like a "laptop chromatography" system (using a laptop computer). I've heard ion chromatography might be best for us. Again, I'm just started to educate myself, so recommendations and additional references are appreciated.

We have a limited budget too, so that's a factor.

Thanks for your suggestions.

[HW Mueller]

If you do it corretly HPLC will be a lot better. The above citation is a comparison of RIA and ELISA with two HPLC methods. Incidentally, I wouldn´t attempt to ionize cortisol.
I never worked with catecholamines, I did extensive lit. searches, quite some years ago, also had extensive discussions with someone who started HPLC of them. I was very glad that interest had vanished among the physicians by the time I was ready to start. I remember that I was going to do it with fluorescence derivatization. The kit by chromsystems does this also, I think.
Anyway, all this refers to the substances in blood, saliva might be a bit easier. Nevertheless, I wouldn´t spend one penny before having completed a nearly exhaustive literature search. Maybe you can even find some personal contact(s) this way.