The determination of small amounts of aluminium by the aurintricarboxylate method

Aluminum Determination, Aluminum Studies. Soil and Plant Analysis of Aluminum by Modification of the Aluminon Method

“…Because chromium levels in plant and soil extracts are very low, no interference was anticipated and it was avoided where aluminum wras separated previously as the hydroxide. Phosphate did not affect the color development at the above levels or where the phosphorusaluminum ratio was 20 to 1 in the method of Strafford and Wyatt (9) or Chenery (3). Separation cf the aluminum as the hydroxide and the phosphate at pH 6.4 was found satisfactory, because the phosphorus to aluminum ratio is reduced greatly.…”

“…Ferric iron interference has been removed by extraction with cupferron in chloroform (9). isopropyl ether (5), or precipitation of sesquioxides with ammonium hydroxide followed by sodium hydroxide to separate aluminum from iron (4) or chromatographic separation (J)• Reduction of the ferric iron to the ferrous state also has been used to avoid iron interference, using thioglycolic acid in the method proposed by Chenery (3) and Chariot (3) or hydroxylamine hydrochloride in the procedure proposed by Peech and English (6).…”

Separation and determination of small quantities of aluminum in steel

“…It will also contain the earth acids and tungsten which have escaped filtration, as well as relatively large amounts of perchloric acid. Further separations of aluminum are based on the fact that aluminum cupferrate is extracted by chloroform from a solution buffered between p H 2 and 5 [ 5 ], but not from a solution 4 N in acid [ 11 , 14 ].…”

Chloroform Extraction of Ferric Cupferrate

“…The magnitude of this value indicates that the hydrogen ion and cupferron concentration may have to be controlled with some care for a satisfactory separation when much iron is present. As a matter of fact, aluminum cupferrate tends to be extracted from sulfuric acid solutions less acid than 4 Ar (3). If the extraction equilibrium is reversible (the reversibility does not seem to have been tested), a better separation can be achieved by applying the principle of retrograde extraction-i.e., the chloroform solution of ferric cupferrate containing a little aluminum cupferrate and excess cupferron is shaken with a hydrochloric acid solution of suitable concentration containing added cupferron.…”