離子(zi)計的使用與維護(hu)
核心提示(shi)：離(li)子(zi)計(ji)(ji)用于測量溶液(ye)中離(li)子(zi)濃度的(de)電化(hua)學分析儀器(qi)。測量H+的(de)也(ye)屬于離(li)子(zi)計(ji)(ji)，我們一(yi)般(ban)稱其PH計(ji)(ji)或(huo)酸(suan)度計(ji)(ji)，一(yi)般(ban)人們指(zhi)的(de)離(li)子(zi)計(ji)(ji)是指(zhi)測量除H+以外其他(ta)離(li)子(zi)的(de)電化(hua)學儀器(qi)
離(li)子(zi)計用于測量溶液中離(li)子(zi)濃度的電(dian)化學(xue)分析儀器。測量H+的也屬于離(li)子(zi)計，我們(men)一(yi)般稱(cheng)其(qi)PH計或酸度計，一(yi)般人們(men)指的離(li)子(zi)計是指測量除H+以外(wai)其(qi)他離(li)子(zi)的電(dian)化學(xue)儀器。
根據離(li)子(zi)(zi)計的(de)(de)測試原理,離(li)子(zi)(zi)選擇(ze)(ze)電(dian)(dian)極(ji)(ji)與(yu)某(mou)種特定離(li)子(zi)(zi)有選擇(ze)(ze)性響(xiang)(xiang)應,當與(yu)離(li)子(zi)(zi)接觸時引起電(dian)(dian)極(ji)(ji)表面電(dian)(dian)位的(de)(de)變化,根據能斯特方程(cheng)式計算(suan)出所(suo)測標本的(de)(de)離(li)子(zi)(zi)活(huo)度或(huo)濃(nong)度值,因此(ci)電(dian)(dian)源(yuan)的(de)(de)微弱變化都能明顯影響(xiang)(xiang)檢(jian)測結果,而且電(dian)(dian)源(yuan)電(dian)(dian)壓(ya)不(bu)穩(wen)定,反復開(kai)關機(ji)會直接損傷電(dian)(dian)極(ji)(ji),導致(zhi)電(dian)(dian)極(ji)(ji)老(lao)化速(su)度加快。因而,有條件者(zhe)應配備具有穩(wen)壓(ya)、抗干擾(rao)的(de)(de)有斷電(dian)(dian)保護的(de)(de)在(zai)線雙向(xiang)斷電(dian)(dian)源(yuan),以消(xiao)除由(you)于線路過載、開(kai)關隨意等(deng)導致(zhi)的(de)(de)電(dian)(dian)壓(ya)不(bu)穩(wen)、噪(zao)音干擾(rao)以及突然斷電(dian)(dian)帶來的(de)(de)不(bu)良影響(xiang)(xiang)。
蛋(dan)白質(zhi)粘附于(yu)(yu)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)膜(mo)(mo)上(shang)可(ke)改(gai)變(bian)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)膜(mo)(mo)電(dian)(dian)(dian)(dian)位(wei),使(shi)標本探測結果產(chan)生誤(wu)差或定標失敗(bai)。有(you)必(bi)要及時對(dui)離子計電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)進行去蛋(dan)白清(qing)(qing)(qing)潔(jie)和(he)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)調(diao)整,清(qing)(qing)(qing)潔(jie)可(ke)使(shi)用(yong)(yong)(yong)含次(ci)氯酸鈉(na)的(de)(de)(de)去蛋(dan)白清(qing)(qing)(qing)潔(jie)液(ye),調(diao)整液(ye)中含NH4、HF2對(dui)Na、++Cl、電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)有(you)活(huo)化(hua)電(dian)(dian)(dian)(dian)位(wei)的(de)(de)(de)作用(yong)(yong)(yong),K用(yong)(yong)(yong)血清(qing)(qing)(qing)浸(jin)(jin)泡也(ye)可(ke)K達(da)到活(huo)化(hua)的(de)(de)(de)效果。較好的(de)(de)(de)電(dian)(dian)(dian)(dian)解(jie)質(zhi)分析儀(yi)(yi)具(ju)有(you)自動(dong)清(qing)(qing)(qing)潔(jie)、調(diao)整的(de)(de)(de)功能(neng)(neng),電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)使(shi)用(yong)(yong)(yong)時間(jian)(jian)較長以(yi)致于(yu)(yu)自動(dong)清(qing)(qing)(qing)潔(jie)不能(neng)(neng)完(wan)全清(qing)(qing)(qing)除蛋(dan)白污垢(gou)時,可(ke)以(yi)將電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)取下浸(jin)(jin)泡在(zai)清(qing)(qing)(qing)潔(jie)液(ye)中一(yi)段(duan)(duan)時間(jian)(jian),用(yong)(yong)(yong)注(zhu)射器(qi)(qi)或洗耳(er)球將清(qing)(qing)(qing)潔(jie)液(ye)從(cong)一(yi)側電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)孔注(zhu)入,反復(fu)沖洗。隨時保(bao)持儀(yi)(yi)器(qi)(qi)處(chu)于(yu)(yu)通電(dian)(dian)(dian)(dian)狀態,確(que)保(bao)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)濕潤(run),必(bi)須關(guan)機時,可(ke)以(yi)采用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)測試的(de)(de)(de)方(fang)法吸入試劑,使(shi)測量倉內(nei)充滿試劑。除仔細(xi)保(bao)養電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)外,兩個同種電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)交替(ti)使(shi)用(yong)(yong)(yong)(不用(yong)(yong)(yong)者甩干(gan)內(nei)充液(ye),存放一(yi)段(duan)(duan)時間(jian)(jian)可(ke)增(zeng)強電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)膜(mo)(mo)的(de)(de)(de)敏感(gan)性(xing)),可(ke)減緩電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)老化(hua)。定標和(he)測量時要將儀(yi)(yi)器(qi)(qi)前門關(guan)上(shang),防止(zhi)外界磁性(xing)干(gan)擾(rao),磁性(xing)干(gan)擾(rao)可(ke)導致電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)嚴重漂(piao)移或紊亂不能(neng)(neng)使(shi)用(yong)(yong)(yong)。
離子計分析儀的(de)定標(biao)、測(ce)試(shi)和(he)沖(chong)洗都必須有試(shi)劑(ji)參與,即使處于待(dai)機狀態,電(dian)極的(de)周圍仍殘留少(shao)量(liang)試(shi)劑(ji),如果試(shi)劑(ji)有問題,其中(zhong)的(de)化學成(cheng)份可能(neng)(neng)對(dui)電(dian)極造(zao)成(cheng)損害,而(er)且對(dui)電(dian)極電(dian)壓值測(ce)試(shi)的(de)結果準確性不(bu)能(neng)(neng)得到保證。原(yuan)則上應該使用原(yuan)廠家(jia)的(de)試(shi)劑(ji),如用非(fei)原(yuan)裝試(shi)劑(ji)應當符(fu)合廠家(jia)要求,對(dui)不(bu)能(neng)(neng)通(tong)過定標(biao)、電(dian)極測(ce)試(shi)電(dian)壓值低于正常范(fan)圍和(he)標(biao)本測(ce)試(shi)結果不(bu)準確的(de)試(shi)劑(ji)要堅決更(geng)換。
離(li)(li)(li)子(zi)計(ji)選(xuan)擇(ze)電(dian)極(ji)(ji)(ji)又稱離(li)(li)(li)子(zi)電(dian)極(ji)(ji)(ji)。一類利用膜(mo)(mo)電(dian)位測(ce)定溶液(ye)(ye)中(zhong)離(li)(li)(li)子(zi)活度(du)或濃度(du)的(de)電(dian)化學傳感(gan)器。1906年由R.克里默最早研究，隨后由德國哈伯(bo)(F.Harber)等(deng)人制成的(de)測(ce)量(liang)溶液(ye)(ye)PH的(de)玻璃電(dian)極(ji)(ji)(ji)是第一種(zhong)離(li)(li)(li)子(zi)選(xuan)擇(ze)電(dian)極(ji)(ji)(ji)，到60年代末，離(li)(li)(li)子(zi)選(xuan)擇(ze)電(dian)極(ji)(ji)(ji)的(de)商品已有(you)20多種(zhong)。離(li)(li)(li)子(zi)選(xuan)擇(ze)電(dian)極(ji)(ji)(ji)具有(you)將溶液(ye)(ye)中(zhong)某種(zhong)特定離(li)(li)(li)子(zi)的(de)活度(du)轉化成一定電(dian)位的(de)能力，其(qi)電(dian)位與溶液(ye)(ye)中(zhong)給定離(li)(li)(li)子(zi)活度(du)的(de)對數成線性關系(xi)。離(li)(li)(li)子(zi)選(xuan)擇(ze)電(dian)極(ji)(ji)(ji)是膜(mo)(mo)電(dian)極(ji)(ji)(ji)，其(qi)核心部件(jian)是電(dian)極(ji)(ji)(ji)尖端的(de)感(gan)應(ying)膜(mo)(mo)。按構造(zao)可(ke)分為(wei)固(gu)體膜(mo)(mo)電(dian)極(ji)(ji)(ji)、液(ye)(ye)膜(mo)(mo)電(dian)極(ji)(ji)(ji)和隔膜(mo)(mo)電(dian)極(ji)(ji)(ji)。
