Multiple choice Which of the following dyes is used as a fluorescent stain? Rhodamine Auramine O Sulforhodamine 101 Texas Red Reveal answer Fill a bubble to check yourself B Correct answer Explanation Auramine O, is a diarylmethane dye used as a fluorescent stain. In its pure form, Auramine O appears as yellow needle crystals. It is very soluble in water and soluble in ethanol.