| 1. |
Eleven bis-azo derivatives of chromotropic acid, containing a COOH group in the o-position to the azo group in one of the benzene rings and NO2, SO3H, AsO3H2, COOH, CH3, Cl, and OCH3 groups in the m- and p-position to the azo group, were studied as reagents for Ca, Sr, Ba, and sulfates.
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| 2. |
Most of the compounds considered are highly sensitive reagents for Sr, Ba, and sulfates.
|
| 3. |
The possibility of a photometric determination of Sr, Ba, and SO
4
2–
with a reagent containing a NO2 group in the p-position to the azo group, i.e., carboxynitrazo, was demonstrated.
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Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 259–265, February, 1970.