• Analytical Science and Technology
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• v.10 no.3
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• pp.216-224
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• 1997

In the study of cyclic voltammogram of rubeanic acid, rubeanic acid has two reduction peaks; first peak is similar with that of $S^{2-}$ and thiourea, which is conceded to by HgS, second peak is very weak and unidentified. The study also describes the differential pulse cathodic stripping voltammetric method for the determination of rubeanic acid. The followings were optimal conditions of rubeanic acid for the study : 0.05M borate buffer solution(pH 10.0) ; an accumulation potential of -0.30V(vs. Ag/AgCl); accumulation time of 120sec. : scan rate of 10mV/sec. The detection limit of trace analysis shows $2.7{\times}10^{-8}M$ of rubeanic and at optimal conditions.

• Analytical Science and Technology
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• v.6 no.5
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• pp.435-442
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• 1993

Carboxymethylated polyamine-polyurea resin loaded with rubeanic acid (RCCPPI resin) was obtained by 1 step chemical reaction between chlorocarboxymethylated polyamine-polyurea(CCPPI) resin as matrix polymer and rebeanic acid. This resin was confirmed with infrared spectrometry, elemental analysis, and thermal analysis(DSC). The adsorption characteristics of the heavy metal's on the resin were studied by measuring distribution coefficient($K_d$) with changing pH of the solutions and frontal chromatography. The enrichment, recovery, and analysis of trace heavy metals, such as cadmium, cerium, copper, nikel, lead, and zinc, in the presence of high concentrations of sodium, calcium, and acetate salts was possible quantitatively by a column packed with the resin at each optimum pH. Preconcentration factors were more than 25. To elute the adsorbed heavy metals on the resin, 0.025M EDTA solution(pH 9.0) was used.

• Journal of Ginseng Research
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• v.26 no.4
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• pp.213-218
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• 2002

Crystalline calcium oxalate occur throughout near)y all plants species in five major forms; styloids, druses, raphids, prisms and sands. These crystals are known to be distributed in specific tissue such as cortex, xylem, phloem, cambium and epidermis. This research was undertaken to identify the occurrence, type, location and ultrastructure of druse crystals in Panax ginseng. In situ visualization, conventional light microscopy, histochemistry and scanning electron microscopy were applied for these purposes. Druse crystals in ginseng were identified as calcium oxalate by silver nitraterubeanic acid histochemistry. Calcium oxalate crystals are observed in nearly all plant organs such as leaf, petiole, peduncle, stem, rhizome, tap root and lateral root except fine root. Most frequent observation of crystals in the leaf and rhizomes were noticed. Three different types of calcium of oxalate druse crystals were identified by scanning electron microscopy.