SPME muaj peb yam yooj yimrho tawmHom: Direct Ectraction SPME, Headspace SPME thiab membrane-tiv thaiv SPME.

1) Direct rho tawm

Nyob rau hauv txoj kev ncaj qha extraction, lub quartz fiber coated nrog raurho tawmnyob ruaj khov theem yog ncaj qha tso rau hauv cov qauv matrix, thiab lub hom phiaj cov khoom raug xa ncaj qha los ntawm cov qauv matrix mus rau extraction nyob ruaj khov theem. Thaum lub sijhawm ua haujlwm hauv chav kuaj, cov txheej txheem agitation feem ntau yog siv los ua kom nrawm nrawm ntawm cov khoom siv tshuaj ntsuam xyuas los ntawm cov qauv matrix mus rau ntawm ntug ntawm cov txheej txheem extraction nyob ruaj khov. Rau cov qauv roj, lub ntuj convection ntawm cov roj yog txaus los ua kom qhov sib npaug ntawm cov khoom siv tshuaj ntsuam xyuas ntawm ob theem. Tab sis rau cov qauv dej, qhov diffusion ceev ntawm cov khoom hauv dej yog 3-4 qhov kev txiav txim siab qis dua li cov pa roj carbon monoxide, yog li kev sib xyaw ua haujlwm zoo yuav tsum tau ua kom tiav sai sai ntawm cov khoom hauv cov qauv. Cov kev sib xyaw uas siv ntau tshaj plaws suav nrog: ua kom cov qauv ntws nrawm, tuav lub taub hau fiber ntau los yog cov thawv coj mus kuaj, rotor stirring thiab ultrasound.

Ntawm qhov tod tes, cov txheej txheem kev sib xyaw ua kom nrawm nrawm ntawm qhov sib txawv ntawm cov khoom hauv cov qauv loj-ntim matrix, thiab ntawm qhov tod tes, txo qhov hu ua "tsawg" cov nyhuv tshwm sim los ntawm txheej txheej ntawm cov kua zaj duab xis tiv thaiv sheath tsim rau. sab nrauv ntawm lub extraction nyob ruaj ruaj theem.

2) Headspace extraction

Nyob rau hauv headspace extraction hom, cov txheej txheem extraction yuav muab faib ua ob kauj ruam:
1. Cov tshuaj ntsuam xyuas tau diffuses thiab nkag mus los ntawm cov kua theem mus rau theem roj;
2. Cov tshuaj ntsuam xyuas tau raug xa mus los ntawm cov roj theem mus rau lub sijhawm rho tawm nyob ruaj khov.
Qhov kev hloov kho no tuaj yeem tiv thaiv qhov kev rho tawm nyob ruaj khov los ntawm kev kis kab mob los ntawm cov khoom siv molecular siab thiab cov khoom tsis muaj volatile hauv qee cov qauv matrices (xws li tib neeg secretions lossis zis). Nyob rau hauv cov txheej txheem extraction no, cov extraction ceev ntawm kauj ruam 2 yog feem ntau ntau dua li qhov diffusion ceev ntawm kauj ruam 1, yog li cov kauj ruam 1 yog tus tswj kauj ruam ntawm extraction. Yog li ntawd, cov khoom tsis hloov pauv muaj qhov nrawm nrawm dua li cov khoom siv hluav taws xob semi-volatile. Nyob rau hauv qhov tseeb, rau volatile Cheebtsam, nyob rau hauv tib cov qauv sib tov tej yam kev mob, lub sij hawm sib npaug ntawm headspace extraction yog luv dua li ntawm ncaj qha extraction.

3) Membrane tiv thaiv extraction

Lub hom phiaj tseem ceeb ntawm kev tiv thaiv membrane SPME yog los tiv thaiv covrho tawmnyob ruaj khov theem los ntawm kev puas tsuaj thaum soj ntsuam cov qauv qias neeg heev. Piv nrog rau headspace extraction SPME, txoj kev no yog qhov zoo dua rau kev rho tawm thiab ua kom muaj zog ntawm cov khoom nyuaj-rau-volatile. Tsis tas li ntawd, cov yeeb yaj kiab tiv thaiv ua los ntawm cov ntaub ntawv tshwj xeeb muab qee qhov kev xaiv rau cov txheej txheem rho tawm.