Chapter 5
S/SL Injection Techniques
Split/Splitless Injector (S/SL)
101
S/SL Injection Techniques
You use different sample injection techniques for split and splitless applications.
Split Injection Technique
In split injection, only a part of the sample transfers into the column. The rest
discharges through the split line.
The ratio of the split flow to the column flow (the split ratio) determines the
amount of sample that enters the chromatographic column. Figure 5-5 illustrates
the gas flows for the split injection technique.
You inject the sample into a glass liner inside the heated vaporization chamber. In
the chamber, the sample undergoes rapid vaporization. The relatively high gas
flow through the injector carries the vaporized sample rapidly down toward the
head of the column.
At the column head, the sample splits in the split ratio. A portion of the sample
goes into the column, while the remainder is carried out the split line. You set the
column flow and the split flow in the
INLET
menu.
Narrow bore columns, which have inherently low column flows, can produce
relatively high split ratios.
NOTE
Hot Empty Needle Injection Technique
To prevent partial sample vaporization within the hot syringe needle and avoid
discrimination of higher boiling components, we recommed to use the Hot Empty Needle
Injection Technique, particularly when performing manual injection. This technique
consists of drawing the sample volume into the syringe barrel followed by a small air gap,
which ensures the syringe needle is empty. You insert the empty needle into the injector,
wait a few seconds, inject the sample rapidly, and immediately remove the syringe.
Using the autosampler (AI/AS 3000 or TriPlus) the Hot Empty Needle Injection Technique
can be automatically selected in the Autosampler Method page of the Data System.
Split injection is suitable for high-concentration sample analysis, headspace
analysis, and isothermal analysis.
Summary of Contents for FOCUS GC
Page 4: ...iv InstructionManual ...
Page 70: ...Chapter 2 The FOCUS GC User Interface Info Diagnostics 70 Instruction Manual ...
Page 92: ...Chapter 4 Column Oven Oven Parameters 92 Instruction Manual ...
Page 124: ...Chapter 6 Purged Packed Column Injector PPKD PPKD Injector Menu 124 Instruction Manual ...
Page 170: ...Chapter 8 Flame Ionization Detector FID Detector Signal Parameters 170 Instruction Manual ...
Page 186: ...Chapter 9 Thermal Conductivity Detector TCD Detector Signal Parameters 186 Instruction Manual ...
Page 242: ...Chapter 13 SOP number P0473 04 E 02 May 2007 242 Instruction Manual ...
Page 336: ...Chapter 16 LAN Option Set up Set Up 336 Instruction Manual ...
Page 344: ...Glossary 344 Instruction Manual C min 1 instead of C min g L 1 instead of g L ...
Page 350: ...Index 350 Instruction Manual ...