Qhov sib txawv tseem ceeb ntawm C8 thiab C18 kem yog tias C8 kem muaj Octylsilane raws li theem nyob ruaj khov thaum C18 kem muaj Octadecylsilane.
Cov kab C8 thiab C18 sib txawv ntawm ib leeg raws li theem nyob ruaj khov. Peb siv cov kab no hauv HPLC (kua kua chromatography). Cov tebchaw uas peb siv hauv cov kab no muaj qhov sib txawv alkyl chain lengths ntawm silane compounds.
C8 Kab yog dab tsi?
C8 kem yog ib daim ntawv ntawm kem tam sim no hauv qee qhov HPLC apparatuses, thiab nws muaj Octylsilane raws li nws cov theem nyob ruaj khov. Thiab, qhov sib xyaw no nyob rau theem nyob ruaj khov muaj 8 carbon atoms hauv nws cov saw hlau alkyl. Tsis tas li ntawd, nws nyiam khaws cov khoom ntawm cov tshuaj ntsuam xyuas tsawg dua li ntawm C18 kem. Yog li ntawd, ib tug compound yuav elute sai nyob rau hauv ib tug C8 kem.
Txawm li cas los xij, nws tsawg dua vim tias nws muaj cov pa roj carbon tsawg dua; qhov ntev ntawm carbon saw ntawm cov compound no nyob rau hauv qhov chaw nres tsheb yog luv luv. Ntxiv mus, nonpolar compounds txav mus rau hauv kem sai nrog C8 kem. Nws yog vim qhov qis hydrophobicity ntawm C8 compound.
C18 yog dab tsi?
C18 kem kuj yog ib daim ntawv ntawm kab uas peb siv hauv HPLC apparatuses, thiab nws muaj Octadecylsilane raws li nws cov theem nyob ruaj khov. Octadecylsilane (nyob rau hauv qhov chaw nres tsheb) muaj 18 carbon atoms nyob rau hauv nws alkyl saw. Tsis tas li ntawd, nws nyiam khaws ntau cov khoom ntawm cov tshuaj ntsuam xyuas thaum piv rau C8 kab. Tus kws tshuaj ntsuam yuav elute qeeb qeeb hauv kab ntawv no.
Daim duab 01: Ib Kab HPLC
Ntxiv mus, C18 yog denser dua ib kab C8. Thiab qhov no ua rau txoj kev ntev ntawm cov tshuaj ntsuam xyuas los ntawm kab. Tsis tas li ntawd, qhov no tso cai rau kev sib cais ntawm ntau lub tebchaw. Lub sijhawm khaws cia ntawm kab no yog siab. Tsis tas li ntawd, lub hydrophobicity ntawm qhov chaw nres tsheb yog siab. Nws tso cai rau qeeb elution ntawm nonpolar compounds los ntawm kab.
Daim ntawv thov ntawm hom kab no feem ntau yog hauv kev tshawb fawb ib puag ncig, kev lag luam tshuaj, tshuaj tshuaj lom neeg, thiab lwm yam.
Qhov txawv ntawm C8 thiab C18 kab yog dab tsi?
C8 kem yog ib daim ntawv ntawm kem tam sim no hauv qee qhov HPLC apparatuses, thiab nws muaj Octylsilane raws li nws qhov chaw nyob ruaj khov. Kab C8 qhia tau hais tias lub sijhawm khaws cia tsawg. Tsis tas li ntawd, tus kws tshuaj ntsuam elutes sai dua hauv kab ntawv no. Nws yog vim hais tias nws muaj ib tug tsawg ntom nyob ruaj theem. C18 kem, ntawm qhov tod tes, kuj yog ib daim ntawv ntawm kab uas peb siv hauv HPLC apparatus, tab sis nws muaj Octadecylsilane raws li nws cov theem nyob ruaj khov. Qhov tseem ceeb tshaj, kab ntawv no qhia tau hais tias lub sijhawm khaws cia siab. Ntxiv rau qhov ntawd, cov tshuaj ntsuam elutes maj mam nyob rau hauv kab ntawv no. Nws yog vim lub siab ntom ntom ntom ntom ntom ntu. Cov nram qab no infographic nthuav tawm cov ncauj lus kom ntxaws qhov sib txawv ntawm C8 thiab C18 kem ua ib sab ntawm kev sib piv.
Summary – C8 vs C18 Kem
C8 thiab C18 yog ob kab sib txawv uas peb tuaj yeem siv hauv HPLC apparatus. Qhov sib txawv tseem ceeb ntawm C8 thiab C18 kem yog tias C8 kem muaj Octylsilane raws li theem nyob ruaj khov whereas C18 kem muaj Octadecylsilane raws li theem nyob ruaj khov.
