SUBJECTS malachite green

Isaeva [181] described a phosphomolybdate method for the determination of phosphate in turbid seawater. Molybdenum titration methods are subject to extensive interferences and are not considered to be reliable when compared with more recently developed methods based on solvent extraction [182-187], such as solvent-extraction spectrophotometric determination of phosphate using molybdate and malachite green [188]. In this method the ion pair formed between malachite green and phosphomolybdate is extracted from the seawater sample with an organic solvent. This extraction achieves a useful 20-fold increase in the concentration of the phosphate in the extract. The detection limit is about 0.1 ig/l, standard deviation 0.05 ng-1 (4.3 xg/l in tap water), and relative standard deviation 1.1%. Most cations and anions found in non-saline waters do not interfere, but arsenic (V) causes large positive errors. 

This term could refer to a number of pigments, iucluding material derived from the natural mineral Seward (1889) states that tile artificial versions were subject to fading and that on his recommendation the British colourmen Rowney s nsed powdered mineral Winsor Newton also stated that they nsed the mineral in 1896. However, Reeves (in a catalogue of about 1898) describe their Malachite green as now made from chromimn and zinc oxides . Martel (1860) indicates that due to the scarcity of the... 

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