hi, I'm using a Peak Performer 1 (Peak Laboratories, www.peaklaboratories.com), it is a relatively small GC that measures both CO and H2, and I get (with calibration) a precision better than 1 ppb at atmospheric CO levels (100 - 200 ppb). It needs carrier gas, so it depends on your application if you can use it. It also needs external calibration and it it not very linear at CO>500 ppb. I used in the field and in the lab, and I am really happy both with the instrument and with the support from the company.

Success!

hai..how about ECOTECH Serinus 30? the analyser Autoranging 0-200ppm (Analogue ranges 0-50ppb to 0-200 ppm) and also selectable unit of concentration mg/m3, μg/m3, ppm, ppb, ppt.

Good Luck

Hi Admir, 

You can check out the Ateknea LEO: http://citisense.ateknea.com/sensors/technicalspecifications

Bets wishes

Many thanks for that, Francisco!

I've used the Langan model T15n. At the time it was the cheapest electrochemical option available.

http://www.langan.biz/Site/CO%20Measurer.html