“…Ghose and Dey (43) used the ring oven in combination with chromatography for the separation and determination of various metals, and Frei and Stockton (86) have combined the use of the ring oven and circular chromatography for trace metal analysis. Trace metal analysis has also been accomplished combining thin-layer chromatography and ring colorimetry (57). Thabet and his coworkers have utilized the ring oven and redox reactions for determining traces of silver (99) and mercury (100).…”