Filter Paper Quantitative Medium 12.5 cm. 100 Filter Circles. Excellent Quality. Pre-treated with double acid. Ash Content 0.01%. Washed with distilled acid. For precise Quantitative Analysis. Medium "Smooth". Ash Content : 0.01%, for Quantitative Analysis. Filter Paper grades have varying particle retention and flow speeds. Fast Papers will retain larger sized particles and Slow Papers will retain smaller sized particles. The ideal choice is a Filter Paper that is fast, and able to retain the precipitate load. We offer a wide range of Qualitative ( indentifying the presence of a substance ) and Quantitative ( determining numerical amounts and percentages of substances ) Filter Papers.