Page 201 - Basic Gas Chromatography

meter microliter methane multiplied Flow 0.13 0.75 0.75 0.75 1.35 1.00 1.35 7.00
SPLIT flow Column (mL/min) 20.0 30.0

FOR suitable 5 a inject for time cm/s. be must Velocity

RATIO a using Then, gas, carrier retention usually are velocity rate flow FOR Linear (cm/sec) 30 30 30 30 30 23 30 50 152 227

SPLIT vent meter). time. the the velocity the 60 mL/min. cancel. (psi)

OF split the flow retention of velocity Li ty = is ty and linear F., rate, column: (mr?) u to units rate/column will units CONDITIONS Pressure 38 4 13 30 11 5 25 2 8 24 127
CALCULATION COLUMNS of out rate electronic or its record and linear u cm. in length average for flow a to velocity the of area = F, the convert ratio: split the flow Split = the mL/min, OPERATING COLUMNS Length Head (meters) 10 12 25 50 25 50 50 10 10 50

IV. OT ON flow the meter flow methane average the column units The the sectional will 60 by calculate Ratio in are values V. Diameter
APPENDIX INJECTION measure First, film (soap of sample Calculate = L where seconds. in convert To cross the by Multiplying Finally, both If APPENDIX CAPILLARY Column (mm) 0.10 0.25 0.32 0.53

Problems longer col- thinfilm are not as but often

Avoid faster, use to column efficiency. pm) injections, volatiles, TCD; and

to are better (530 fast for purity. hydrocarbons. ECD sample.
How is It increase very slow. films for of

CG: columns slow). to Megabore small, too Thicker high of light condensation

II. shorter are sizes wm. very is Nj um. one and Essential
Appendix 25m; plates (but sample 320 or 250 require Hy; or He 0.5 or gas; carrier remove HO gas. make-up with FID. avoid hot;

Columns Length—start with have more small and i.d., with 4m 100 gas—use 0.2 with efficient. less use proper to use sensitivity detector

Capillary umns small i.d.—start efficient; Carrier dy—start usually Always Use scrubbers necessary, increases the Keep

C. 1. 2. 3. 4. Detectors A. B. If Cc. D.
186 IV.