Page:NIOSH Manual of Analytical Methods - 2506.pdf/5

 ACETONE CYANOHYDRIN: METHOD 2506, Issue 2, dated 15 August 1994 - Page 5 of 5

the column. Determine the length of transfer line needed from the column end fitting to the bottom of the detector jet. Force a piece of 1.6-mm OD PTFE tubing equal to this length plus the length of the PTFE plug, through the center to the back end of the plug. Insert the PTFE plug, back end first, into the opening at the detector end of the column. Push the compression fitting over the column where the PTFE plug was inserted. Attach the column to the chromatograph, pushing the transfer line as close as possible to the bottom of the detector jet. Gently tighten the compression fitting around the column. Once the column has been installed in the instrument, pressurize it with nitrogen. Check the column for a flow of 33 mL/min. Check the compression fittings for leaks; gently tighten them as necessary. After it has been determined that there is flow through the column, condition it at 125 °C for 1 to 2 h. A diagram of a column where the transfer line has been replaced is shown in Figure 1.

3.2-mm OD column 3.2-mm OD compression fitting 2.6-mm OD plug 1.6-mm OD PTFE transfer line

Injector Detector Figure 1. All-PTFE gas chromatograph system used for the determination of acetone cyanohydrin.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition