1、電泳介質的(de)pH值(zhi)

溶(rong)液的(de)pH值(zhi)決(jue)定(ding)(ding)帶電(dian)(dian)(dian)物(wu)質(zhi)(zhi)的(de)解(jie)離(li)(li)程度，也決(jue)定(ding)(ding)物(wu)質(zhi)(zhi)所帶凈電(dian)(dian)(dian)荷(he)的(de)多(duo)少(shao).對蛋(dan)(dan)白質(zhi)(zhi)，氨基(ji)酸等類似(si)兩(liang)性電(dian)(dian)(dian)解(jie)質(zhi)(zhi)，pH值(zhi)離(li)(li)等電(dian)(dian)(dian)點越(yue)遠，粒子所帶電(dian)(dian)(dian)荷(he)越(yue)多(duo)，泳動速度越(yue)快，反之(zhi)越(yue)慢。因此，當(dang)分(fen)離(li)(li)某一(yi)種(zhong)混合物(wu)時，應選擇一(yi)種(zhong)能擴大各種(zhong)蛋(dan)(dan)白質(zhi)(zhi)所帶電(dian)(dian)(dian)荷(he)量差別的(de)pH值(zhi)，以(yi)利于(yu)各種(zhong)蛋(dan)(dan)白質(zhi)(zhi)的(de)有效分(fen)離(li)(li).為了(le)保證電(dian)(dian)(dian)泳過程中溶(rong)液的(de)pH值(zhi)恒定(ding)(ding)，必須采用緩沖溶(rong)液。

緩沖液的離子強度

溶液的(de)(de)離子強(qiang)度(du)(du)(du)（Ion intensity）是指溶液中各離子的(de)(de)摩爾濃(nong)度(du)(du)(du)與離子價(jia)數平方(fang)的(de)(de)積的(de)(de)總和的(de)(de)1/2.帶(dai)電顆粒的(de)(de)遷(qian)移(yi)率與離子強(qiang)度(du)(du)(du)的(de)(de)平方(fang)根(gen)成反(fan)比(bi)。低離子強(qiang)度(du)(du)(du)時(shi)(shi)，遷(qian)移(yi)率快(kuai)，但(dan)離子強(qiang)度(du)(du)(du)過低，緩沖(chong)液的(de)(de)緩沖(chong)容量(liang)小，不易維持pH恒定.高(gao)離子強(qiang)度(du)(du)(du)時(shi)(shi)，遷(qian)移(yi)率慢，但(dan)電泳譜(pu)帶(dai)要比(bi)低離子強(qiang)度(du)(du)(du)時(shi)(shi)細(xi)窄(zhai)。通(tong)常溶液的(de)(de)離子強(qiang)度(du)(du)(du)在(zai)0.02～0.2之間。

I=1/2∑CiZi2 (I：離子(zi)強度；Ci：離子(zi)的摩爾濃度；Zi：離子(zi)價數. )

0.154M NaCl溶液的離子強度(du)為：

I= 1/2(0.154×12+0.154×12)=0.154

0.015M Na2SO4溶液的離(li)子(zi)強度(du)為：

I= 1/2(0.015×2×12+0.015×22)=0.045

3、電場強度

電(dian)(dian)(dian)(dian)(dian)(dian)(dian)場強(qiang)度(du)(du)(du)（電(dian)(dian)(dian)(dian)(dian)(dian)(dian)勢梯度(du)(du)(du)Electric field intensity）是(shi)指每厘米的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位降(電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位差或(huo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位梯度(du)(du)(du)）.電(dian)(dian)(dian)(dian)(dian)(dian)(dian)場強(qiang)度(du)(du)(du)對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)速度(du)(du)(du)起(qi)著(zhu)正比作(zuo)用，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)場強(qiang)度(du)(du)(du)越高(gao)(gao)，帶電(dian)(dian)(dian)(dian)(dian)(dian)(dian)顆粒移動速度(du)(du)(du)越快。根據(ju)實驗的(de)(de)(de)(de)需要，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)可分(fen)(fen)(fen)(fen)為兩(liang)種(zhong)：一種(zhong)是(shi)高(gao)(gao)壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)，所用電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)在500～1000V或(huo)更高(gao)(gao).由(you)于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)高(gao)(gao)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)時間(jian)短（有(you)的(de)(de)(de)(de)樣品(pin)需數分(fen)(fen)(fen)(fen)鐘），適用于(yu)低分(fen)(fen)(fen)(fen)子化合物的(de)(de)(de)(de)分(fen)(fen)(fen)(fen)離(li)(li)(li)(li)，如氨基酸，無(wu)機離(li)(li)(li)(li)子，包括(kuo)部分(fen)(fen)(fen)(fen)聚焦電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)分(fen)(fen)(fen)(fen)離(li)(li)(li)(li)及(ji)(ji)序列電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)的(de)(de)(de)(de)分(fen)(fen)(fen)(fen)離(li)(li)(li)(li)等。因電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)高(gao)(gao)，產(chan)熱(re)(re)量大(da)，必須(xu)裝有(you)冷(leng)卻(que)裝置，否則熱(re)(re)量可引(yin)起(qi)蛋(dan)白(bai)質等物質的(de)(de)(de)(de)變性而(er)不能分(fen)(fen)(fen)(fen)離(li)(li)(li)(li)，還因發熱(re)(re)引(yin)起(qi)緩沖(chong)液中水分(fen)(fen)(fen)(fen)蒸發過多，使支(zhi)持物（濾紙，薄膜或(huo)凝膠(jiao)等）上離(li)(li)(li)(li)子強(qiang)度(du)(du)(du)增加(jia)，以及(ji)(ji)引(yin)起(qi)虹吸(xi)(xi)現象(xiang)（電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)槽內液被吸(xi)(xi)到(dao)支(zhi)持物上）等，都會影響物質的(de)(de)(de)(de)分(fen)(fen)(fen)(fen)離(li)(li)(li)(li).另一種(zhong)為常(chang)壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)泳(yong)，產(chan)熱(re)(re)量小，室(shi)溫在10～25℃分(fen)(fen)(fen)(fen)離(li)(li)(li)(li)蛋(dan)白(bai)質標本(ben)是(shi)不被破壞(huai)的(de)(de)(de)(de)，無(wu)需冷(leng)卻(que)裝置，一般(ban)分(fen)(fen)(fen)(fen)離(li)(li)(li)(li)時間(jian)長。

4、電滲現象

在(zai)電(dian)場(chang)中(zhong)液體(ti)(ti)對于一個固(gu)體(ti)(ti)的(de)(de)固(gu)定相(xiang)(xiang)相(xiang)(xiang)對移(yi)(yi)動(dong)稱為(wei)電(dian)滲(shen)(shen)(shen).在(zai)有(you)載體(ti)(ti)的(de)(de)電(dian)泳(yong)(yong)中(zhong)，影(ying)響電(dian)泳(yong)(yong)移(yi)(yi)動(dong)的(de)(de)一個重要因(yin)素是(shi)電(dian)滲(shen)(shen)(shen)。最(zui)常遇到的(de)(de)情(qing)況是(shi)γ-球蛋白，由原(yuan)(yuan)點(dian)向(xiang)負極移(yi)(yi)動(dong)，這就是(shi)電(dian)滲(shen)(shen)(shen)作(zuo)用(yong)所(suo)(suo)(suo)引(yin)起的(de)(de)倒移(yi)(yi)現象(xiang).產生電(dian)滲(shen)(shen)(shen)現象(xiang)的(de)(de)原(yuan)(yuan)因(yin)是(shi)載體(ti)(ti)中(zhong)常含(han)有(you)可電(dian)離(li)的(de)(de)基團，如(ru)濾紙中(zhong)含(han)有(you)羥基而(er)帶負電(dian)荷，與(yu)濾紙相(xiang)(xiang)接觸的(de)(de)水溶液帶正(zheng)電(dian)荷，液體(ti)(ti)便(bian)向(xiang)負極移(yi)(yi)動(dong)。由于電(dian)滲(shen)(shen)(shen)現象(xiang)往往與(yu)電(dian)泳(yong)(yong)同(tong)時(shi)存在(zai)，所(suo)(suo)(suo)以帶電(dian)粒子(zi)的(de)(de)移(yi)(yi)動(dong)距(ju)(ju)離(li)也(ye)受(shou)電(dian)滲(shen)(shen)(shen)影(ying)響；如(ru)電(dian)泳(yong)(yong)方(fang)向(xiang)與(yu)電(dian)滲(shen)(shen)(shen)相(xiang)(xiang)反(fan)，則實際電(dian)泳(yong)(yong)的(de)(de)距(ju)(ju)離(li)等于電(dian)泳(yong)(yong)距(ju)(ju)離(li)加上(shang)電(dian)滲(shen)(shen)(shen)的(de)(de)距(ju)(ju)離(li).瓊脂(zhi)中(zhong)含(han)有(you)瓊脂(zhi)果(guo)膠(jiao)，，其(qi)中(zhong)含(han)有(you)較多(duo)的(de)(de)硫酸(suan)根(gen)，所(suo)(suo)(suo)以在(zai)瓊脂(zhi)電(dian)泳(yong)(yong)時(shi)電(dian)滲(shen)(shen)(shen)現象(xiang)很明(ming)顯(xian)，許多(duo)球蛋白均向(xiang)負極移(yi)(yi)動(dong)。除去了瓊脂(zhi)果(guo)膠(jiao)后的(de)(de)瓊脂(zhi)糖用(yong)作(zuo)凝膠(jiao)電(dian)泳(yong)(yong)時(shi)，電(dian)滲(shen)(shen)(shen)大為(wei)減(jian)弱.電(dian)滲(shen)(shen)(shen)所(suo)(suo)(suo)造成(cheng)的(de)(de)移(yi)(yi)動(dong)距(ju)(ju)離(li)可用(yong)不帶電(dian)的(de)(de)有(you)色染(ran)料或有(you)色葡聚糖點(dian)在(zai)支持物的(de)(de)中(zhong)心，以觀(guan)察電(dian)滲(shen)(shen)(shen)的(de)(de)方(fang)向(xiang)和距(ju)(ju)離(li)。