Powder Purified Talc, For Industrial, Grade: Bio-tech Grade

Talc derived from deposits that are known to contain associated asbestos is not suitable for pharmaceutical use. The manufacturer is responsible for demonstrating by the test for amphiboles and serpentines that the product is free from asbestos. The presence of amphiboles and of serpentines is revealed by X-ray diffraction or by infrared spectrophotometry (see A and B). If detected, the specific morphological criteria of asbestos are investigated by a suitable method of optical microscopy to determine whether tremolite asbestos or chrysotile is present, as described below. Examine by infrared spectrophotometry (2.2.24). In the range 740 cm-1 to 760 cm-1 using scale expansion, any absorption band at 758 cm-1 1 cm-1 may indicate the presence of tremolite or of chlorite. If the absorption band remains after ignition of the substance at 850C for at least 30 min, it indicates the presence of the tremolite. In the range 600 cm-1 to 650 cm-1 using scale expansion, any absorption band or shoulder may indicate the presence of serpentines. Examine the substance prepared as discs using potassium bromide R.