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Alcian Blue-PAS (ABPAS)
The Alcian Blue/PAS Stain Kit is used to identify acidic and neutral mucins. This procedure clearly separates the acidic and neutral mucins by color and can be used to distinguish all mucins in tissue sections. The positive charge imparted by isothiouronium groups’ results in the attraction of the alcian blue dye molecules to the anionic sites in mucin molecules. The blue color is due to the presence of copper in the molecule. The 3% acetic acid solution (pH 2.5) with alcian blue is believed to form salt linkages with the acid groups of acid mucopolysaccharides. The tissue sections are first oxidized using periodic acid which oxidizes the vicinal bonds in these sugars, breaking the carbon-carbon bonds resulting in the pair of aldehydes. The Schiff’s reagent reacts with the aldehyde groups forming colorless, unstable dialdehyde compound which transforms to insoluble magenta-colored complex by restoration of quinoid chromophoric grouping.
The Alcian Blue/PAS Stain Kit is used to identify acidic and neutral mucins. This procedure clearly separates the acidic and neutral mucins by color and can be used to distinguish all mucins in tissue sections. The positive charge imparted by isothiouronium groups’ results in the attraction of the alcian blue dye molecules to the anionic sites in mucin molecules. The blue color is due to the presence of copper in the molecule. The 3% acetic acid solution (pH 2.5) with alcian blue is believed to form salt linkages with the acid groups of acid mucopolysaccharides. The tissue sections are first oxidized using periodic acid which oxidizes the vicinal bonds in these sugars, breaking the carbon-carbon bonds resulting in the pair of aldehydes. The Schiff’s reagent reacts with the aldehyde groups forming colorless, unstable dialdehyde compound which transforms to insoluble magenta-colored complex by restoration of quinoid chromophoric grouping.
