Generally used to quantify the experimental filter paper called quantitative filter paper, because of his ash <0.007%. Ash We know that the filter paper is calcined at high temperature after the residue, generally burned after leaving most of the metal can not burn. We converted this 0.007% to ppm (ppm can be understood as 10-6) equal to 70ppm, because this is the quality of 70, we assume that the general metal ion molecular weight of 100 (copper molecular weight of 63), 70/100 = 0.7ppm. If you add half of the metal in the ash, then 0.7 / 2 = 0.35ppm. Now we see that in fact the quantitative filter paper about the metal impurity content in this left and right (excluding the assumption that the general is also several times the increase decreases, not 10 times the increase decreases). 1ppm in the chromatographic analysis is a big number, in many cases the customer analysis of the sample concentration may be in the case of 0.001ppm, so for chromatographic analysis, especially metal plasma analysis, our quantitative filter paper impurity content is very high The value. In fact, for most of the big names, do trace analysis, ion detection will not choose quantitative filter paper. Will be more inclined to quartz filter paper and other types.
