Preventive Maintenance
Conditioning columns
back of nut). Adjust the septum purge flow rate to no more than
6ml/min.
c.Cap inlet fittings into detector(s) to prevent entry of air and/or contaminants.
3.Establish a stable flow of carrier gas through the column. He is preferred; however, N1 is adequate for conditioning packed columns. Do not use H1 because it vents into the column oven during conditioning.
a.For 1/8•and 1/4•inchcolumns (with 2 mm id), a flow rate of about
30ml/min is sufficient; for 1/4•inchcolumns (with 4 mm id), a flow rate of about 50 ml/min is adequate.
b.For a rigid glass capillary column (with 0.25 mm id), establish a head pressure (in psi) equal to about half the column length (in meters). For example, a 50 m column should have a head pressure of about 25 psi (172 kPa).
c.For a fused silica capillary column, establish a column head pressure (in psi) equal to column length (in meters).
4.Set oven temperature to 100^C for about an hour. Then slowly raise oven temperature to the conditioning temperature for the column (never greater than the maximum temperature limit for the column; 30^C less than the maximum is usually sufficient).
Caution Overheating may shorten column lifetime.
Conditioning may continue overnight for packed columns and can be much less for capillary columns.
5.If the conditioned column is not to be used immediately, remove it from the oven and cap its ends to prevent entry of air, moisture, and/or contaminants.
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