In order to maintain precise channels, chromatography paper
was chosen to cut into tree-shaped sheet and Y-shaped sheet. Treeshaped
sheet was cut with seven branches (4 mm
×
45 mm) and
a stem (8 mm
×
55 mm) (as shown in Scheme 2a) [20]. Y-shaped
sheet was cut into a strip with two branches (3 mm
×
45 mm) and
a stem (6 mm
×
55 mm) (as shown in Scheme 2c). The detection
zones were 30 mm from the top of the stem and substrate zones
were 5 mm from the top of the stem (Scheme 2b and d).