The Determination of Inorganic Sulphate in Sodium Lauryl Sulphate
The official method for the determination of inorganic sulphate in sodium lauryl sulphate is time‐consuming. Separation of organic and inorganic sulphate via the lead salts followed by complexometry leads to a rapid and convenient method with readily reproducible results.
Complexometric Determination of Sulfate
A simple and rapid method for the determination of sulfate in materials obtained during extraction of uranium from ores is based on precipitation as lead sulfate from acid solution containing isopropyl alcohol. The precipitate is filtered and redissolved in an excess of measured standard (ethylenedinitrilo)tetraacetic acid (EDTA) solution. The excess of the latter is then backtitrated with a standard zinc chioride solution and Eriochrome Black T as indicator. A detailed study of the optimum conditions for the precipitation of lead suifate has been carried out, and the degrees of interference of phosphate, arsenate, iron, and uranium ions have been tested. The method is virtually free of interferences and gives accurate results in the range 0.1 to 100% sulfates the time required for a determination is about 30 to 45 minutes. (auth)
Mesozoic rifting and basin inversion along the northern African Tethyan margin: an overview
Abstract The northern African Tethyan margin registered three major rifting episodes from the latest Palaeozoic-earliest Mesozoic to the earliest Cenozoic. Break-up of Gondwana was initiated in the late Carboniferous. Along the northern African-Arabian plate margin rifting propagated westward from the northeastern Arabian margin to Morocco during the Permian and Triassic, and was accompanied by Mid-Late Triassic-earliest Liassic extensive alkaline flow basalts. Rifting continued during the Liassic, e.g. in the Moghrebian Atlas troughs. A second stage of rifting occurred in the Late Jurassic and continued into, or was rejuvenated during, the Early Cretaceous. Along the east Mediterranean margin, some large E-W trending rifts formed, often with associated volcanism, e.g. southern Sirt and Abu Gharadig. Most researchers believe the oceanization of the eastern Mediterranean basin occurred at this time. Flexural subsidence affected the Moghrebian Atlas, including the Riffian-Tellian domain, where a thick flysch series was deposited. Two short-lived, but widespread and tectonically important, compressional or wrench-dominated events occurred during the Santonian and the latest Maastrichtian. From Morocco to Oman, most sedimentary basins were folded and inverted at these times. The Santonian event resulted from onset of the collision between the African-Arabian and Eurasian plates. New stress-fields favoured NE-SW extension along the African plate margin, generating or rejuvenating some rifts, e.g. in the Euphrates trough and in the Libya-Tunisia region (northwestern Sirt, Pelagian Sea). Rifting and magmatism continued in these regions into the Paleocene. During the Mesozoic, therefore, the northern margin of the African-Arabian plate registered both rifting resulting in the oceanization of the Tethys and rifting resulting from the initiation of the closure of the Tethys. The intraplate domain exhibited echoes of the tectonic events affecting the margin.