| 摘要 |
PURPOSE:To calibrate zero span with good reproducibility and simplicity, by carrying out calibration using a solid material which has a similar absorbance of ultraviolet rays to that of a standards solution. CONSTITUTION:When a zero-span calibration of a nephelometer that measures organic contaminants in sample water by determination of absorbance of ultraviolet rays, is carried out, solid material having similar absorbance of ultraviolet rays to the standard solution, for example, a metallic wire gauze having constant mesh is used, A wire gauze 5 possessing similar absorbance of ultraviolet rays to the standard solution is set up on a optical axis of said nephelometer composed of a low voltage mercury-vapor lamp 1, slit 2, photodetector 4 and etc., to calibrate zero adjusting to zero value. Subsequently, the wire gauze 5 is replaced by a wire gauze having absorbance similar to that of the standard solution of potassium hydrogen phthalate and the span calibration is performed in accordance with the span value. Thus zero-span calibration is carried out in a simple manner. |
