principles of gas chromatography(vn)
DESCRIPTION
Gas ChromatographyTRANSCRIPT
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SC K KH C BN
Copyright 2008 by LTD
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I. L thuyt chung v sc k ctn Sc k :
Chromatogram
Time
Detector
Column
Injector
Sample Injection
ABAB
B
AB
A B
Peak A Peak B
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1. Cc thng s c bnn Thi gian lu:
Retention Time (tr)n Th tch lu: Retetion
Volume (Vr)n B rng peak:
Baseline Width (W)n Thi gian lu cht:
Void Time (tm)n Th tch cht: Void
Volumn (Vm)
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a. phn gii Resolution(R)
n V d: vi R = 0.5 th phn din tch b che ph l 0.13%
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n Cc k thut nng cao phn gii:a) phn gii ban ub) Nng cao phn gii da vo hiu nng ctc) Nng cao phn gii da vo chn lc ct
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b. H s dung lng Capacity factor (k)
k o c kh nng lu gi ca pha tnh i vi cht ha tan.
tr = tr - tm: thi gian lu hiu chnh
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c. chn lc ct Column Selectivity
n H s chn lc Selectivity factor (a): l t s ca cc hs dung lng ca hai cht ha tan
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d. Hiu nng ct Column Efficiency
n a l thuyt Theoretical plate
N: s a l thuyt
L: chiu di ct
H: chiu cao a l thuyt
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2. Ti u ha phn gii
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a. S dng k ti u ha phn gii
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b. S dng chn lc ti u ha phn gii
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c. S dng hiu nng ct ti u ha phn gii
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Cc h s thc nghim tc ng n s bnh rng mi sc k. a hng-Mutiple Paths Khuych tn dc-Longitudinal Diffusion S truyn khi-Mass Transfer
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n Phng trnh Van Deemter
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III. Sc k kh
n S khi ca mt my sc k kh in hnh
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1. Pha ng
n Vic la chn loi kh mang ph thuc vo u d thit b.
n Tc pha ng: Ct nhi: 25-150 mL/min Ct mao qun: 1-25 mL/min
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2. Ct sc kn Ct nhi: 2-6 m chiu di x 2-4 mm ng knh trong x 37-44 mm
hoc 250-354 mm
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a. Sc k lng kh Gas-Liquid Chromatography (GLC)
n Ct mao qun WCOT Wall-coated open
tubular columns SCOT Support-coated open
tubular columns PLOT Porous-layer open
tubular columns
WCOT SCOT PLOT
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b. La chn pha tnh cho GLC
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3. B phn tim mu
OnOn--column column InjectorInjector
SplitSplit//Splitless Splitless InjectorInjector
PTV InjectorPTV Injector Packed and Packed and widewide--boreborecolumnscolumns
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Cc k thut tim thng dngSplit Splitless Direct vaporizing forwide bore capillary column
Direct vaporizing forpacked column
Car
rie r
gas
Split
Sept
um P
urge
column
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4. u dn Flame Ionization Detector (FID): s dng cho cc hp cht hu
c
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n Thermal Conductivity Detector (TCD): s dng cho cc kh v c v cc hp cht hu c nng cao
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n Electron Capture Detector (ECD): s dng cho cc hp cht i lc in t
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n Flame Photometric Detector (FPD): s dng cho cc hp cht hu c sulphur v phosphorus
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n Flame Themionic Detector (FTD): s dng cho cc hp cht hu c nitrogen v phosphorus
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5. ng dng nh lngn Mi trng:
Phn tch cc cht nhim hu c trong khng kh, nc, nc thi.
Phn tch cc hp cht hu c d bay hi.
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n Y t: phn tch thuc
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n Cc sn phm tiu dng: phn tch mi, gia v, hng liu.
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n Cng nghip du m: phn tch cc sn phm du m, bao gm xng du, nht.
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6. ng dng nh tnhn Khi s dng GC vi u d MS hoc FT-IR, thng tin ph c dng
nh danh cc cht.n Khi s dng cc u d thng thng, phi s dng cc phng php
khc: Thm vo mu mt lng cht phn tch kh nghi v theo di s tng ca
chiu cao peak. So snh thi gian lu ca mu chun v mu th trong cng mt iu kin
phn tch.
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7. nh gin Thang hot ng:
FID v TCD c th dng cho mt lng ln mu phn tch. Cc u d khc nh ECD, MS yu cu mt lng nh cht phn tch
(~ pg)n ng: khong 1-5%.n chnh xc: khong 1-5%.n nhy: TCD
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Thank you!