Page 113 - Basic Gas Chromatography

99 start also initial splitless than sample carried aligned and thick flow as not trace cold and tech-

must must the chromatogra- higher ‘‘on-column” are require normal is better on-column a or vaporized observed.
Purge Initially Hl in Later you You both Finally, 30°C small a vapors precisely megabore, than resolution be cold liner is injection

Septum Liner losed Clas Opened injector. program. optimize valve. good For points injection,” injecting the the 0.53-mm-i.d. techniques faster the can from inlet cold sample decomposition best the

——+» Glass > Column splitless time-consuming; and split compounds. boiling ‘direct involves where inserting a these with precautions advantages result a either the and is

VPS. SSIS SNL SISSON X\ Capillary { typical of is It temperature solvent, of opening the have are injection liner glass means usually of Both columns these The quantitation into heated sample on-column

wey section Cross disadvantages. must you volatile a time the volatile for must interest inlets capillary Direct a into On-column column, column. the wide-diameter with injection. quantitation. good and injected is rapidly is Minimal cold

Systems Gas ———»> 6.9. Fig. several and column; with and well-suited of peaks of types on-column.’ smaller) or column. capillary inside and Even mL/min). splitless or split good resolution sample liquid injector cold column. the compounds,

Inlet Carrier has cold sample temperature not is first Inlets other wL 1 the to the into injections capillaries with and high A The through thermolabile
Capillary Splitless a with the dilute column injection the phy solvent. the Other Three “cold and (usually directly needle making film (~10 rates as good analysis Both injections. column. carried For

Inlets discrimi- sample but solvent injection of out the this is in by higher over the or
and open) the 6.9), mL/min) 1 condensed. mL/min), swept only While band vaporized these sensitivity and
Columns Purge Septum 5/mi/mn Vent Split Valve Needle (Always mil/mn 50 e.g. Column sometimes that so injected. injection (Fig. volatile a in heated the about solvent are 50 about rapidly injections. initially column. narrow a are of column pharmaceutical,

Capillary ———> e.g. Liner Glass Capillary injector. split process the sample sample the split diluted in injected of rate and of rate are port splitless and the refocused into analytes resolution improved the the enters environmental,

a << typical splitting in of as is sample is (flow sample (flow with programmed, through these High is sample
SES of solutes pL slowly injection
SSSA hardware 5 both opened carried being time, injection
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AMM SON SM SSS section the respresentative The to and is the essential are more for
Zz iy LIL Cross that is weight same closed. 1 and where valve in is temperature and analytes later some chromatographed. splitless analysis
Gags ————» Fig. 6.8. disadvantage molecular not is the uses initially methanol) vaporized is column split the vapors left purge now vaporized sample At and observed. of to 20- 50-fold trace

Carrier high column the Injection injection is valve or sample cold a seconds, residual Septum is column solvent is the solvent. column is analytes advantage improved samples.
second against hexane The onto 45 system. residual big Typically is

A entering Splitless Splitless split carried any The volatile happening, hot boiling The biomedical
98 nates the (like port. After and the the the split. result