Ten microliters of the calibrator were added to the sample substrate (Whatman 1-Chr-grade
chromatography paper, 2 X 2 cm) and allowed to dry overnight in the fume hood before being extracted and analyzed as detailed above.
By operating under the optimized conditions, that is, by using dichloromethane/isopropanol (9:1 v/v) as a spray solvent mixture, limits of quantitation of about 0.1 ng/mL were achieved, with a sensitivity gain of 5-50-fold in comparison to
chromatography papers.
Due to the sensitivity of
chromatography paper, always store it in an airtight container, away from [CO.sub.2], [SO.sub.2], acid and alkaline fumes--as well as moisture and bright light.
Chromatography paper is used by chemical engineers to determine simply the filterability of muds and slurries.
They did this by applying six samples of ink to a strip of
chromatography paper which was dipped in distilled water.
This device is the "Hemoglobin Color Scale." (1,2,3) It consists of a series of printed colors on a card with special
chromatography paper onto which a blood sample is placed.