Identification of Category of Blank Gel Pen Ink by TLC

TLC was applied to identify category of ink used in black gel pen.In the proposed method,ethanol-water(1+1) solution was used as extraction solvent,and a mixed solution,containing n-butanol,absolute ethanol,water and acetic acid mixed in the ratio of 14 to 10 to 6 to 1 by volume,was used as developing solvent.Based on the number of developed spots,their colors and Rf values,37 kinds of black ink of gel pens made in different places were identified and classified into 13 categories by this method.