 Actually the dye does not necessary contain all 4 substituents but might contain 2 or 3 of them and have various geometric isomers.But anyhow the manufacture of 8GX by ICI had stopped by Mid-1970s because of environmental hazards and very small lots were available that were received from alternate sources.Only recently Alcian Blue has been re manufactured in bulk using safer procedures but the newer product does not have the suffix X (or S) since the manufacture process (and the exact product composition) is somewhat different.