We have used high pH anion-exchange chromatography to analyze low level (below $20{mu}M$) $alpha$-D-glucose-1-phosphate (G-1-P) that can be used as a cytostatic compound, an antibiotic, and immunosuppressive drug. Our chromatographic method afforded excellent peak resolution and seletivity for glucose-6-phosphate and various maltooligosaccharides as well as G-1-P. The pulsed amperometric detector yielded linear response on G-1-P ranging from 2 - $20{mu}M$, giving slope of $4.8{ imes}10^4$(peak area/${mu}M$). The detection limit was $2{mu}M$. This method was applied to the purification of thermophilic $alpha$-glucan phosphorylase from Thermus caldophilus. The technique will be extremely useful in future studies concerning carbohydrate metabolism in living organisms.