Orthophenanthroline method

The compositions of solutions were determined by a timed spectro-photometric method. The technique was a modification of a standard ferron-orthophenanthroline method for aluminum (27, 28) and is identical in principle to a method developed by Turner (22). The method was modified in the following manner. 

We studied the complexes of lanthanides and Am (III] by potentiometry. This method is based on pH variations due to the competition between H+ and the metal ions for the coordination site of orthophenanthroline (pka - 5.2], as shown by equation (4]. 

The calculation results are shown in table II. We also report formation constants determined from spectrophotometry for Ho and Nd, and by solvent extraction for Er. Without going into detail for these two methods, it may be noted that the results show fair agreement. That fact points out the inner sphere character of orthophenanthrolinium lanthanous complexes. The main absorption band of Am (III] is modified by the presence of orthophenanthroline. We used these spectral variations to calculate the formation constants of Am (III], as described in the previous paragraph. As for azide complexes, we observed that Am monoorthophe-nanthroline is more stable than the equivalent lanthanide complex, and for the bis orthophenanthroline species, the difference... 

Using a titrimetric iron determination with titanous chloride, Remmer (R3) obtained for e N a value of 11.09 as an average of 11 determinations. Minkowski (M7) found t N = 11.15, using a spectrophotometric method involving the use of orthophenanthroline. These values are in fair agreement with our results (see Section 2.1.5 and Table 2). An indirect proof of cn =... 

Certain positively charged ion-exchangers can be used for anion-selective electrodes. Charged metal salts of appropriately substituted orthophenanthrolines— M(o-phen)3 —result in good electrodes for nitrate, fluoroborate, or perchlorate by forming ion-association complexes with these anions. The CIO " electrode, in particular, has few interferences and perchlorate is a difficult ion to measure by almost any other method. A dimethyl-distearyl-ammonium ion, R N, can be used as an ion-exchanger in an electrode that has fair selectivity for chloride. 

Different light-induced A P values were observed in R.rubrum chromatophores by different methods ranging from 60 to 110 mV [see ref.10]. There are no data on AV generated by Rps.vlridls chromatophores in the literature. The light-induced membrane potential were sensitive to inhibitors of the cyclic electron transport uncouplers and also Orthophenanthroline an electron transport inhibitor of the reaction center (not shown). 

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