Acidity of several chromotropic acid azo derivatives

Chloride anion interference in the spectrophotometric determination of Arsenazo III

“…nAzIII + mCl ^AzIII"Clm (1) culated a maximum at 570 nm. On the contrary, Budesinsky (23) reported the association of two protons with the azo groups for AzIII in perchloric acid.…”

Development of a new measurement method for serum calcium with chlorophosphonazo-III

“…Figure 1 depicts the constitutional formula of CPZ-III, which has properties of combination for actinide, calcium, magnesium,and so on in the ratio of 1:1 -1:3 as a chelate compound. According to Budesinsky, 11…”

“…Figure 1 depicts the constitutional formula of CPZ-III, which has properties of combination for actinide, calcium, magnesium,and so on in the ratio of 1:1–1:3 as a chelate compound. According to Budesinsky, 11 the dissociation constants (p K a) of CPZ-III are −1.1, −1.1, 0.6, 0.8, 1.5, 2.5, 5.47, 7.20, 12.15 and 15.3 (20°C). Its reaction solution, after chelating, becomes purple or violet.…”

Development of novel measurement assay for calcium in serum by the chlorophosphonazo-III vanadate method

“…In the present situation, it would be extremely useful to develop a reagent for calcium determination that is inexpensive and stable, which depends on a chelating method, and that gives satisfactory performance. We considered that chlorophosphonazo-III (2,7-bis(4-chloro-2-phosphonophenylazo)-1,8-dihydroxy-3,6-naphthalenedisulphonic acid, disodium salt; CPZ-III), 9–11 which is a chelating compound used for the analysis of dried diagnostic reagents, 12 might be a suitable substance to fulfil these criteria. Fergusons et al 13 has reported that the CPZ-III spectrophotometric procedure can be used to determine additively calcium and magnesium concentrations in the same sample.…”