There are provided systems, devices and methods for operating a light source with a light sensor to provide a desired light output. The housing defines a pocket open to the channel and sized to both collect a metered dose of the sample liquid, and to retain the collected dose by capillary force when the channel is emptied. The second FBG has second transmittance distribution or second reflectance distribution. cooling and depressurizing the mixture resulting from the previous step; andiv. The epoxy resins are preferably a Bisphenol A or Bisphenol F Epichlorohydrin based epoxy or epoxy novalac.