可(ke)充式和(he)非可(ke)充式pH復合(he)電極的差異
核心提示：pH復合電(dian)極分為可(ke)(ke)(ke)充式（補(bu)液(ye)型(xing)）和非可(ke)(ke)(ke)充式（凝(ning)膠式）。可(ke)(ke)(ke)充式pH復合電(dian)極外殼(ke)上有一加(jia)液(ye)孔(kong)，當電(dian)極的外參比溶(rong)液(ye)流失后，可(ke)(ke)(ke)將加(jia)液(ye)孔(kong)打開，重新(xin)補(bu)充KC1溶(rong)液(ye)。
pH復(fu)合(he)(he)電(dian)極(ji)(ji)分為可充式（補液(ye)型(xing)）和非可充式（凝膠(jiao)式）。可充式pH復(fu)合(he)(he)電(dian)極(ji)(ji)外殼上有一加(jia)液(ye)孔，當電(dian)極(ji)(ji)的外參比(bi)溶液(ye)流(liu)失(shi)后，可將加(jia)液(ye)孔打開(kai)，重新補充KC1溶液(ye)。而非可充式pH復(fu)合(he)(he)電(dian)極(ji)(ji)內(nei)裝(zhuang)凝膠(jiao)狀KC1，不易(yi)流(liu)失(shi)也無加(jia)液(ye)孔。
對溶液中氫離(li)子活(huo)度有響應，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)位隨之而變化(hua)的(de)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)稱(cheng)為(wei)pH指示(shi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)或pH測(ce)(ce)量(liang)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)。pH指示(shi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)有氫電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、銻電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)和玻(bo)(bo)璃(li)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)等幾種(zhong)，但最常(chang)用(yong)(yong)的(de)是(shi)(shi)玻(bo)(bo)璃(li)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)。玻(bo)(bo)璃(li)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)是(shi)(shi)由玻(bo)(bo)璃(li)支(zhi)桿，以及由特殊成份組(zu)成的(de)對氫離(li)子敏感的(de)玻(bo)(bo)璃(li)膜組(zu)成。玻(bo)(bo)璃(li)膜一(yi)般呈球泡(pao)狀，球泡(pao)內充入(ru)(ru)內參(can)比(bi)溶液，插入(ru)(ru)內參(can)比(bi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)（一(yi)般用(yong)(yong)銀(yin)/氯化(hua)銀(yin)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)），用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)帽封接引出電(dian)(dian)(dian)(dian)(dian)線，裝上插口(kou)，就成為(wei)一(yi)支(zhi)pH指示(shi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)。單(dan)獨一(yi)支(zhi)pH指示(shi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)是(shi)(shi)無法進行(xing)測(ce)(ce)量(liang)的(de)，它(ta)必(bi)須和參(can)比(bi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)一(yi)起才能(neng)測(ce)(ce)量(liang)。
對溶(rong)液(ye)中氫離子活度無響(xiang)應(ying)，具(ju)有已知和恒定的(de)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)(dian)(dian)位的(de)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)稱為參(can)比(bi)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)。參(can)比(bi)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)有硫酸亞(ya)汞(gong)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、甘汞(gong)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)和銀(yin)/氯化銀(yin)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)等(deng)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)等(deng)幾種。最(zui)常(chang)用的(de)是(shi)(shi)甘汞(gong)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)和銀(yin)/氯化銀(yin)。把pH玻璃電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、參(can)比(bi)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)和溫(wen)度補償電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)組(zu)合(he)在(zai)一起的(de)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)就是(shi)(shi)pH復(fu)合(he)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)。復(fu)合(he)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)最(zui)大的(de)好(hao)處就是(shi)(shi)便于安裝(zhuang)，標定與(yu)使用。pH復(fu)合(he)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)主要由(you)玻璃電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)（由(you)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)球(qiu)泡、玻璃支持桿(gan)等(deng)組(zu)成）、外參(can)比(bi)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、外參(can)比(bi)溶(rong)液(ye)、溫(wen)度補償電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、液(ye)接界(jie)、電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)帽、電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)導(dao)線、等(deng)組(zu)成。
可充(chong)式(shi)(shi)pH復合(he)電(dian)(dian)極(ji)的特(te)點(dian)是(shi)參(can)(can)比溶液(ye)(ye)有較(jiao)(jiao)高的滲透速率(lv)，液(ye)(ye)接界電(dian)(dian)位穩定(ding)重現，測量(liang)精度較(jiao)(jiao)高。而且(qie)當(dang)(dang)參(can)(can)比電(dian)(dian)極(ji)減(jian)少(shao)或受污染后可以(yi)補充(chong)或更換KCl溶液(ye)(ye)，但缺點(dian)是(shi)使(shi)用(yong)較(jiao)(jiao)麻煩(fan)。可充(chong)式(shi)(shi)pH復合(he)電(dian)(dian)極(ji)使(shi)用(yong)時(shi)應將(jiang)加(jia)液(ye)(ye)孔打(da)開，以(yi)增加(jia)液(ye)(ye)體(ti)壓力(li)，加(jia)速電(dian)(dian)極(ji)響應，當(dang)(dang)電(dian)(dian)解液(ye)(ye)液(ye)(ye)面較(jiao)(jiao)低時(shi)，應及時(shi)補充(chong)新的電(dian)(dian)解液(ye)(ye)。
非可充式pH復(fu)合(he)電(dian)極的(de)(de)(de)(de)特(te)點(dian)是維護(hu)簡單(dan)使用方便，因(yin)(yin)此也(ye)得到廣泛的(de)(de)(de)(de)應用。但(dan)作為實(shi)驗室pH電(dian)極使用時(shi)，在長期和連(lian)續的(de)(de)(de)(de)使用條(tiao)件(jian)下，液接界處的(de)(de)(de)(de)KCl濃度會減少，影(ying)響測試(shi)精度。因(yin)(yin)此非可充式pH復(fu)合(he)電(dian)極不(bu)(bu)用時(shi)，應浸在電(dian)極浸泡液中，這樣下次測試(shi)時(shi)電(dian)極性能會很(hen)好，而大部分實(shi)驗室pH電(dian)極都不(bu)(bu)是長期和連(lian)續的(de)(de)(de)(de)測試(shi)，因(yin)(yin)此這種結(jie)構(gou)對(dui)精度的(de)(de)(de)(de)影(ying)響是比較小的(de)(de)(de)(de)。
用(yong)于確定化學反應(ying)過程的最熟悉最古老(lao)的零電流(liu)測(ce)量方法(fa)恐怕就是pH測(ce)量。一(yi)般來講，pH測(ce)量就是用(yong)來確定某(mou)種溶液的酸(suan)堿度。
