可充式(shi)和非可充式(shi)pH復合電(dian)極的差異
核心提(ti)示：pH復(fu)合(he)電(dian)(dian)極分為可(ke)充(chong)(chong)式（補液型）和非可(ke)充(chong)(chong)式（凝(ning)膠(jiao)式）。可(ke)充(chong)(chong)式pH復(fu)合(he)電(dian)(dian)極外殼上有一加液孔，當電(dian)(dian)極的外參比溶液流(liu)失后，可(ke)將(jiang)加液孔打開(kai)，重新補充(chong)(chong)KC1溶液。
pH復合(he)(he)電極分為可充式(shi)（補液(ye)(ye)(ye)型）和非可充式(shi)（凝膠式(shi)）。可充式(shi)pH復合(he)(he)電極外殼上有一(yi)加(jia)液(ye)(ye)(ye)孔(kong)，當電極的(de)外參比(bi)溶(rong)液(ye)(ye)(ye)流失后，可將加(jia)液(ye)(ye)(ye)孔(kong)打開，重新(xin)補充KC1溶(rong)液(ye)(ye)(ye)。而非可充式(shi)pH復合(he)(he)電極內裝(zhuang)凝膠狀KC1，不(bu)易(yi)流失也無加(jia)液(ye)(ye)(ye)孔(kong)。
對(dui)溶液中(zhong)氫離子活(huo)度有響應(ying)，電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)位(wei)隨(sui)之而變化的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)稱為pH指(zhi)(zhi)示(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)或pH測量(liang)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)。pH指(zhi)(zhi)示(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)有氫電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)、銻(ti)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)和玻璃(li)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)等幾(ji)種，但最常用的(de)(de)是(shi)玻璃(li)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)。玻璃(li)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)是(shi)由(you)玻璃(li)支桿，以及由(you)特殊成份組(zu)成的(de)(de)對(dui)氫離子敏感的(de)(de)玻璃(li)膜組(zu)成。玻璃(li)膜一般呈球泡(pao)狀，球泡(pao)內(nei)充入內(nei)參比(bi)溶液，插入內(nei)參比(bi)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)（一般用銀(yin)/氯化銀(yin)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)），用電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)帽封接引出電(dian)(dian)(dian)(dian)(dian)(dian)線，裝上插口(kou)，就成為一支pH指(zhi)(zhi)示(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)。單獨一支pH指(zhi)(zhi)示(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)是(shi)無法進行測量(liang)的(de)(de)，它必須(xu)和參比(bi)電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)一起才能測量(liang)。
對溶液中氫離子活度(du)無響應，具有(you)已(yi)知(zhi)和(he)恒定的(de)(de)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)電(dian)(dian)位的(de)(de)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)稱(cheng)為參(can)比(bi)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)。參(can)比(bi)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)有(you)硫酸(suan)亞汞電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、甘汞電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)和(he)銀(yin)/氯化(hua)銀(yin)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)等(deng)(deng)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)等(deng)(deng)幾種。最(zui)常(chang)用的(de)(de)是(shi)甘汞電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)和(he)銀(yin)/氯化(hua)銀(yin)。把pH玻璃電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、參(can)比(bi)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)和(he)溫度(du)補(bu)償電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)組合在一(yi)起的(de)(de)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)就(jiu)是(shi)pH復合電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)。復合電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)最(zui)大的(de)(de)好處就(jiu)是(shi)便于安裝，標定與使(shi)用。pH復合電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)主要由玻璃電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)（由電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)球泡(pao)、玻璃支持桿等(deng)(deng)組成）、外參(can)比(bi)電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、外參(can)比(bi)溶液、溫度(du)補(bu)償電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)、液接界、電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)帽、電(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)導線、等(deng)(deng)組成。
可(ke)充(chong)式pH復合電(dian)(dian)極(ji)的特點(dian)是參(can)比溶液(ye)(ye)有較(jiao)(jiao)高的滲透速率，液(ye)(ye)接界電(dian)(dian)位(wei)穩定重(zhong)現，測(ce)量精度較(jiao)(jiao)高。而(er)且當參(can)比電(dian)(dian)極(ji)減少或(huo)受污染后可(ke)以補充(chong)或(huo)更換KCl溶液(ye)(ye)，但缺點(dian)是使用(yong)較(jiao)(jiao)麻(ma)煩。可(ke)充(chong)式pH復合電(dian)(dian)極(ji)使用(yong)時應將加液(ye)(ye)孔(kong)打(da)開，以增加液(ye)(ye)體壓力(li)，加速電(dian)(dian)極(ji)響應，當電(dian)(dian)解液(ye)(ye)液(ye)(ye)面較(jiao)(jiao)低時，應及時補充(chong)新(xin)的電(dian)(dian)解液(ye)(ye)。
非可(ke)(ke)充式(shi)pH復合電(dian)(dian)極的(de)特點(dian)是(shi)維護簡單使用(yong)方便，因(yin)此(ci)也得到廣(guang)泛(fan)的(de)應(ying)用(yong)。但作為(wei)實驗(yan)室pH電(dian)(dian)極使用(yong)時(shi)，在(zai)長(chang)期和(he)連續的(de)使用(yong)條件下，液接界處的(de)KCl濃(nong)度會減(jian)少，影(ying)響(xiang)測(ce)(ce)試(shi)精(jing)度。因(yin)此(ci)非可(ke)(ke)充式(shi)pH復合電(dian)(dian)極不(bu)用(yong)時(shi)，應(ying)浸在(zai)電(dian)(dian)極浸泡液中，這樣(yang)下次測(ce)(ce)試(shi)時(shi)電(dian)(dian)極性能會很(hen)好，而大部分(fen)實驗(yan)室pH電(dian)(dian)極都不(bu)是(shi)長(chang)期和(he)連續的(de)測(ce)(ce)試(shi)，因(yin)此(ci)這種結(jie)構對精(jing)度的(de)影(ying)響(xiang)是(shi)比(bi)較(jiao)小的(de)。
用于確(que)定(ding)化學反應(ying)過(guo)程(cheng)的最熟(shu)悉最古老的零電流(liu)測量方(fang)法恐怕就是pH測量。一(yi)般(ban)來講(jiang)，pH測量就是用來確(que)定(ding)某種(zhong)溶液(ye)的酸堿度。
