Presentation is loading. Please wait.

Presentation is loading. Please wait.

Capillary electrophoresis. Electrophoretic migration Z i : charge # of component i e 0 : elemental charge [ 1.602×10 -19 C ] E=V/L ( V : applied voltage.

Similar presentations


Presentation on theme: "Capillary electrophoresis. Electrophoretic migration Z i : charge # of component i e 0 : elemental charge [ 1.602×10 -19 C ] E=V/L ( V : applied voltage."— Presentation transcript:

1 Capillary electrophoresis

2

3 Electrophoretic migration Z i : charge # of component i e 0 : elemental charge [ 1.602× C ] E=V/L ( V : applied voltage ; L : length ) r i : stokes radius of i component η : viscosity of the medium [Pa · S] V i 0 : migration velocity of i component (1) (2)

4 μ i 0 : electrophoretic mobility μ i 0 和 (q, η, r i ) 有關 Electroosmotic flow (EOF) (3) (4) μ eo : electroosmotic mobility (cm 2 /Vs) (5) (6) ξ : zeta potential (V) 和 pH 值, ionic strength 有關 η : viscosity of double layer ~ η (bulk)

5

6

7  =  r    / 

8

9 + - n EOF -+ + n - Net 毛細管電泳的向量圖

10 Effective Mobility and Apparent Mobility

11 if no EOF (7) (8) (9) (10)

12 Efficiency (11) (12) (13) (14) (15)

13 (16) (17) (18) 對某一 analyte, μ 和 D 是 constant V 固定 D 愈小 N 愈大 對大分子分離有利

14 Resolution (19) (20) (21) (22) :平均距離 (cm) :平均速度

15 代入 (24) EOF 存在 (23) (24) (25) (26) EOF 和 electrophoretic 反方向則 μ eo ↑ R s ↑ Best Resolution 分離時間很長

16 (22) 式 R s =column eff. × selectivity factor selectivity →separation factorαin chromatography Buffer composition Complex formation 1. Borate complexation 2. ion pairing 3. inclusion complex 4. metal complexation Organic modifier 1.After the polarity & viscosity of the mobile phase EOF & electrophoretic mobility changed 2. 增加 solubility of analyte 3. reduce zeta potential

17 Reversal of EOF Using a Cationic Surfactant

18

19

20

21

22 Micellar Electrokinetic Chromatography fraction of analyte in aqueous phase fraction of analyte in micelle migration velocity (V s ) : t R, t 0, t mc : migration time of analyte, aqueous phase, and micelle k’ : capacity factor n mc : no. of analyte molecules incorporated into the micelle n aq : no. of analyte molecules in aqueous phase (1) (2) (3) (6) (5) (7) (4)

23 (5)(6)(7) 代入 (4) (micelle 停在 capillary) << t 0 =∞ EOF is completely suppressed, in MEKC EOF is not essential. 這時分析物向正 (+) 移動, k’ 值愈大移動速率愈快 (8) (10) (9)

24 Resolution t mc →∞ 兩式相等 t mc →∞ 固定相 (11)

25 Effect of the capacity factor t 0 /t mc =0 t mc =∞ conventional chromatography large capacitybetter resolution lead to in MEKC large k’ unfavor (11) 式最後一項 →0 optimum k’ 和 t 0 /t mc 有關 將 (12) 式微分 (12) (13)

26 capacity factor k : distribution coefficient V mc,V aq : volumes of micelle and aqueous phases : specific volume of micelle when << 1 k’ vs conc. of surfactant C sf linear if k is constant 可調整 C sf 來調整 k‘ RP-HPLC 調整 phase ratio 對 k‘ 改變小 (15) (16) (14) (17) (V mc <

27 Effect of EOF on the resolution < 1 >> 愈小 R s 愈大 separation factor ← micelle (stationary phase in RP-HPLC) aqueous (mobile phase in RP-HPLC) type of surfactants : hydrophilic (ionic group) hydrophobic (from 11 式 )

28

29

30

31 Chiral Capillary Electrophoresis (CCE)

32

33

34 Separation Mode: Capillary Gel Electrophoresis (CGE)

35 CGE: Protein Size Separation Using SDS Linear Polymer Solutions

36 Separation Mode: Capillary Isoelectric Focusing (CIEF)

37 Detection: Direct UV Detection

38

39

40 Detection: Indirect UV Detection

41 Lab-on-a-chip or CE on chip

42 Photograph of the microdevice with attached transfer capillary

43  -TAS concept: Miniture-Total Chemical Analysis system.


Download ppt "Capillary electrophoresis. Electrophoretic migration Z i : charge # of component i e 0 : elemental charge [ 1.602×10 -19 C ] E=V/L ( V : applied voltage."

Similar presentations


Ads by Google