Basic dyes, basic dye(s), also known as basic dyes. Dyes that can dissociate to form cationic pigments in aqueous solutions are classified as cationic dyes. Since basic dyes have poor color fastness to light and color to washing after dyeing fibers, they are now rarely used in fabric dyeing, and are mainly used for the coloring of cultural and educational supplies, paper, and the manufacture of lakes.
For basic dyes, most of their chromophores are organic bases, and a few of them form salts (chlorides) with inorganic acids. When the dye is dissociated in an aqueous solution, it is a cationic dye because the pigment group has a positive charge. It is characterized by bright color, magnificent fluorescence (mainly rose red, yellow, orange, etc.), and strong coloring power, and a deep and rich color can be obtained with a small amount of dye. The color fastness and light fastness are poor, but it has better fastness for acrylic fiber (polyacrylonitrile fiber). Basic dyes do not color cellulose fibers. In the early 1970s, my country adopted the grafting method to dye silk with cationic dyes.
After this type of dye ionization, the dye ion is positively charged and can combine with acidic substances to form a salt. The basic dyes commonly used in microbiology laboratories include methylene blue, methyl violet, ammonium oxalate crystal violet, acetic magenta, basic fuchsin, neutral red, malachite green and safranin. In general, bacteria are easily Basic dyeing.
Common basic dyes are: basic brilliant green (green 1), basic green (green 4), basic rose essence B (violet 10), basic blue, basic violet 5BN (violet 3), alkali Orange block (orange 2), basic fuchsine (purple 14), basic bright yellow O (yellow 2), basic brown G (brown 1), basic brilliant blue BO (blue 7), basic blue G ( Blue 1), Basic Blue B (Blue 5), Basic Lake Blue BB (Blue 9), Basic Scarlet (Basic Flag Red), Basic Black, Basic Dark Green, Basic Brilliant Blue, etc.