Scope:

The standard test method to analyse liquid chlorine for low levels of water ASTM E1754-17a uses infrared spectrophotometry. It can be used for water concentrations ranging from 0.5 to 15 mg/kg (ppm). The values stated are stated in SI units.

Test Procedure:

In the ASTM E1746-17a test method, a sample of liquid chlorine is introduced into a special infrared cell and maintained as a liquid under its own pressure. A spectrometer scans from 400 to 4400 wavenumbers of the infrared transmission spectrum of liquid chlorine. The ratio between this spectrum and the one obtained from the nitrogen-filled infrared cell previously is calculated and is then converted to absorbance. The net absorbance of the water band at 1596 wavenumbers, relative to a reference at 1663 wavenumbers, is determined. The amount of water corresponding to this net absorbance is determined from a calibration curve prepared from the infrared absorbances of standards that contain known concentrations of water in liquid chlorine.

Specimen size:

400 ml to 1000 ml liquid chlorine sample for testing is required for ASTM E1754-17a test method.

Data:

Most infrared spectrometers now permit a “ratio” of one transmission spectrum to another to be obtained. Calibration curves herein are generated in this manner; spectra of those obtained after spiking are ratioed to those obtained before spiking. This ratioed transmission spectrum is then converted to absorbance units. The reports are given in SI units.

Conclusion:

ASTM E1754-17a helps in determining the water levels in liquid chlorine which could be important in identifying the problems in its application.