做化(hua)學(xue)分(fen)(fen)(fen)析(xi)要用到(dao)的(de)(de)玻璃儀器(qi),應(ying)在每次實(shi)驗完(wan)畢之后洗凈干(gan)(gan)燥備用。用于不同(tong)實(shi)驗的(de)(de)儀器(qi)對干(gan)(gan)燥有不同(tong)的(de)(de)要求(qiu)(qiu),一般定(ding)量分(fen)(fen)(fen)析(xi)中(zhong)的(de)(de)燒杯、錐形瓶等儀器(qi)洗凈即(ji)可使用,而用于有機(ji)化(hua)學(xue)實(shi)驗或有機(ji)分(fen)(fen)(fen)析(xi)的(de)(de)儀器(qi)很多是要求(qiu)(qiu)干(gan)(gan)燥的(de)(de),有的(de)(de)要求(qiu)(qiu)無(wu)水跡(ji),有的(de)(de)要求(qiu)(qiu)無(wu)水,應(ying)根據(ju)不同(tong)要求(qiu)(qiu)來干(gan)(gan)燥儀器(qi)。
玻璃儀器的潔凈標準
在(zai)化學(xue)實驗時,為避免雜質進(jin)(jin)入(ru)反(fan)應(ying)體系(xi),影響反(fan)應(ying)條件及實驗現象(xiang)的觀察,必須使用清潔的玻璃儀器。儀器的清洗應(ying)在(zai)每次(ci)實驗之(zhi)后立即(ji)進(jin)(jin)行。這是(shi)因為一方(fang)(fang)面清楚(chu)當時污物的性質,以便(bian)采取合適的方(fang)(fang)式清除(chu);另一方(fang)(fang)面也為下一次(ci)實驗做好準備(bei)。
玻璃儀器的一般清洗方法
選擇合適的毛刷,將毛刷和儀器用水打濕后,用毛刷沾上去污粉刷洗儀器內外壁(磨口瓶不宜用去污粉,以免損壞磨口),當玻璃儀器上污物除去后,再用自來水沖洗干凈。
若(ruo)要求潔(jie)凈程度很(hen)高時,還需用(yong)(yong)(yong)少量蒸餾水(shui)淋(lin)洗(xi)二至三次。一個洗(xi)凈的(de)(de)玻璃儀(yi)器(qi)其瓶(ping)壁上應不(bu)掛(gua)水(shui)珠(zhu),若(ruo)有水(shui)珠(zhu)時,需重新洗(xi)滌。應該指(zhi)出(chu)的(de)(de)是,洗(xi)滌后的(de)(de)儀(yi)器(qi)不(bu)能(neng)用(yong)(yong)(yong)抹布、濾紙(zhi)等擦干。有些反(fan)應殘(can)余物(wu)用(yong)(yong)(yong)去(qu)污粉不(bu)易洗(xi)凈,可根據污物(wu)的(de)(de)具體情況采(cai)用(yong)(yong)(yong)價(jia)格較低或回收的(de)(de)有機(ji)溶劑浸(jin)泡(pao)或用(yong)(yong)(yong)稀酸、堿(jian)液來(lai)清(qing)(qing)洗(xi),但不(bu)能(neng)盲目使用(yong)(yong)(yong),以(yi)免造(zao)成浪費和事故(gu)(例如,殘(can)留浪的(de)(de)儀(yi)器(qi),若(ruo)用(yong)(yong)(yong)丙(bing)酮(tong)清(qing)(qing)洗(xi)將(jiang)會產生強(qiang)力催淚劑——溴化(hua)丙(bing)酮(tong))。儀(yi)器(qi)壁上的(de)(de)陳跡可以(yi)采(cai)用(yong)(yong)(yong)洗(xi)液浸(jin)泡(pao)后清(qing)(qing)洗(xi)除去(qu)。
洗滌禁忌須知
1.常法(fa)洗(xi)(xi)滌(di)儀(yi)器。洗(xi)(xi)刷儀(yi)器時,應(ying)首先將手(shou)用(yong)肥皂(zao)洗(xi)(xi)凈,免得手(shou)上的油污附在儀(yi)器上,增加(jia)洗(xi)(xi)刷的困難。如儀(yi)器長久(jiu)存放(fang)附有(you)塵灰,先用(yong)清水(shui)沖(chong)去(qu),再按要(yao)(yao)求選用(yong)潔凈劑(ji)洗(xi)(xi)刷或洗(xi)(xi)滌(di)。用(yong)蒸餾水(shui)沖(chong)洗(xi)(xi)時,要(yao)(yao)用(yong)順壁沖(chong)洗(xi)(xi)方法(fa)并充分震蕩,經蒸餾水(shui)沖(chong)洗(xi)(xi)后的儀(yi)器,用(yong)指示劑(ji)檢(jian)查應(ying)為中性。
2.作痕量金屬分(fen)析的玻璃儀(yi)器,使用1:1~1:9HNO3溶液(ye)浸泡(pao),然(ran)后(hou)進行常法洗滌(di)。
3.進行(xing)熒光分(fen)析時,玻璃儀器(qi)應避免使用洗(xi)衣粉洗(xi)滌(因洗(xi)衣粉中含有(you)熒光增白劑(ji),會給分(fen)析結果帶來誤差)。
4.分析致(zhi)癌物質時,應選用適當(dang)洗(xi)消夜浸泡,然后(hou)再按常法洗(xi)滌。
常見干燥方式
進行化(hua)(hua)學(xue)實(shi)(shi)驗所使用(yong)的儀(yi)(yi)器(qi)(qi)(qi)除了需(xu)(xu)要(yao)清洗外常常還(huan)需(xu)(xu)要(yao)干(gan)燥。水(shui)(shui)的存在(zai)有時會影響(xiang)化(hua)(hua)學(xue)反應的速(su)度或(huo)產率,有時甚至使化(hua)(hua)學(xue)反應無法進行。對于一般無水(shui)(shui)要(yao)求的實(shi)(shi)驗,只需(xu)(xu)將(jiang)(jiang)儀(yi)(yi)器(qi)(qi)(qi)倒(dao)置晾干(gan)便可使用(yong);而對于絕對無水(shui)(shui)的實(shi)(shi)驗,則(ze)需(xu)(xu)將(jiang)(jiang)儀(yi)(yi)器(qi)(qi)(qi)置烘箱中或(huo)熱氣(qi)(qi)流烘干(gan)器(qi)(qi)(qi)上烘干(gan)。若需(xu)(xu)急用(yong),可將(jiang)(jiang)洗凈的儀(yi)(yi)器(qi)(qi)(qi)用(yong)少量(liang)(liang)乙醇或(huo)丙酮蕩洗,再用(yong)吹(chui)(chui)風機吹(chui)(chui)干(gan)。必須(xu)特別指(zhi)出的是,無論用(yong)何種方法干(gan)燥的儀(yi)(yi)器(qi)(qi)(qi),都必須(xu)讓儀(yi)(yi)器(qi)(qi)(qi)冷至室溫時才能取出,否則(ze)熱的儀(yi)(yi)器(qi)(qi)(qi)驟冷時,水(shui)(shui)氣(qi)(qi)將(jiang)(jiang)在(zai)器(qi)(qi)(qi)壁上凝(ning)聚。只要(yao)不是容量(liang)(liang)儀(yi)(yi)器(qi)(qi)(qi)(量(liang)(liang)筒、滴定管(guan)、移液(ye)管(guan)等)都可以烘干(gan)。
1.晾(liang)干
不急用的(de)(de),要求(qiu)一般干(gan)燥,可(ke)(ke)在純水涮洗后(hou),在無(wu)塵處倒置(zhi)晾(liang)干(gan)水分,然(ran)后(hou)自然(ran)干(gan)燥。可(ke)(ke)用安(an)有斜木釘(ding)的(de)(de)架子和(he)帶有透(tou)氣孔的(de)(de)玻(bo)璃柜(ju)放置(zhi)儀器。
2.烘(hong)干
洗凈(jing)的(de)(de)儀器控去(qu)水(shui)分,放(fang)(fang)在電(dian)烘(hong)(hong)箱(xiang)中(zhong)烘(hong)(hong)干(gan),烘(hong)(hong)箱(xiang)溫(wen)度為105~120℃烘(hong)(hong)1h左右(you)。也可(ke)放(fang)(fang)在紅外燈干(gan)燥箱(xiang)中(zhong)烘(hong)(hong)干(gan)。此法(fa)適用于一般儀器。稱(cheng)量(liang)用的(de)(de)稱(cheng)量(liang)瓶等烘(hong)(hong)干(gan)后要放(fang)(fang)在干(gan)燥器中(zhong)冷(leng)卻和保存(cun)。帶實(shi)心玻璃(li)塞的(de)(de)及(ji)厚(hou)壁儀器烘(hong)(hong)干(gan)時(shi)要注意慢(man)慢(man)升溫(wen)并且溫(wen)度不(bu)可(ke)過高,以免烘(hong)(hong)裂(lie),量(liang)器不(bu)可(ke)放(fang)(fang)于烘(hong)(hong)箱(xiang)中(zhong)烘(hong)(hong)。硬質試管可(ke)用酒精燈烘(hong)(hong)干(gan),要從底部烘(hong)(hong)起,把試管口向下,以免水(shui)珠倒(dao)流把試管炸裂(lie),烘(hong)(hong)到無水(shui)珠時(shi),把試管口向上趕凈(jing)水(shui)汽。
3.熱(re)(冷)風吹干
元素分(fen)析儀(yi)(yi)(yi)對于急于干(gan)燥的(de)儀(yi)(yi)(yi)器(qi)(qi)或(huo)不(bu)適合放入(ru)(ru)烘箱的(de)較(jiao)大(da)的(de)儀(yi)(yi)(yi)器(qi)(qi)可(ke)用(yong)吹干(gan)的(de)辦(ban)法(fa),通常用(yong)少量乙(yi)醇、丙酮(或(huo)最后再用(yong)乙(yi)醚)倒入(ru)(ru)已控去(qu)水分(fen)的(de)儀(yi)(yi)(yi)器(qi)(qi)中搖(yao)洗控凈溶(rong)劑(ji)(溶(rong)劑(ji)要回收),然后用(yong)電吹風吹,開始用(yong)冷(leng)(leng)風吹1~2min,當大(da)部分(fen)溶(rong)劑(ji)揮發后吹入(ru)(ru)熱(re)風至完全干(gan)燥,再用(yong)冷(leng)(leng)風吹殘余的(de)蒸汽,使其不(bu)再冷(leng)(leng)凝(ning)在容(rong)器(qi)(qi)內。此(ci)法(fa)要求(qiu)通風好(hao),防(fang)止中毒,不(bu)可(ke)接(jie)觸明火,以(yi)防(fang)有機溶(rong)劑(ji)爆炸。
烘箱中烘干應注意什么?
準確的(de)說玻(bo)(bo)璃(li)儀器都不(bu)(bu)能放入烘箱(xiang)中烘干(gan),能放入的(de)玻(bo)(bo)璃(li)器具其作用(yong)是用(yong)于盛放而不(bu)(bu)是測量(liang)用(yong)的(de)。比如,燒杯、燒瓶、圓底燒瓶適合烘干(gan),玻(bo)(bo)璃(li)制(zhi)品的(de)量(liang)具類(帶有(you)刻度)滴定管(guan)、移(yi)液管(guan)、量(liang)筒不(bu)(bu)適合烘干(gan)。
烘干(gan)玻璃(li)容易溫(wen)(wen)度(du)不(bu)可(ke)過高,做好是(shi)100度(du)以(yi)下,取出(chu)時注(zhu)意帶(dai)耐高溫(wen)(wen)手套,防止燙傷,另外(wai),最(zui)好將烘箱溫(wen)(wen)度(du)到(dao)達45度(du)以(yi)下(或(huo)者(zhe)常溫(wen)(wen))再取出(chu)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi),高溫(wen)(wen)下不(bu)可(ke)取出(chu),防止驟冷驟熱導致玻璃(li)碎(sui)裂。做化(hua)(hua)學(xue)分析(xi)(xi)要(yao)(yao)(yao)(yao)(yao)用(yong)(yong)(yong)到(dao)的(de)玻璃(li)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi),應(ying)在(zai)每次實(shi)驗(yan)(yan)完(wan)(wan)畢之(zhi)后(hou)(hou)(hou)洗(xi)凈(jing)(jing)干(gan)燥(zao)備(bei)(bei)(bei)用(yong)(yong)(yong)。用(yong)(yong)(yong)于不(bu)同(tong)(tong)(tong)實(shi)驗(yan)(yan)的(de)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)對干(gan)燥(zao)有(you)(you)(you)不(bu)同(tong)(tong)(tong)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu),一般定(ding)(ding)量(liang)分析(xi)(xi)中的(de)燒(shao)杯(bei)、錐形瓶(ping)等(deng)(deng)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)洗(xi)凈(jing)(jing)即可(ke)使用(yong)(yong)(yong),而用(yong)(yong)(yong)于有(you)(you)(you)機(ji)化(hua)(hua)學(xue)實(shi)驗(yan)(yan)或(huo)有(you)(you)(you)機(ji)分析(xi)(xi)的(de)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)很多是(shi)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)干(gan)燥(zao)的(de),有(you)(you)(you)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)無(wu)水跡,有(you)(you)(you)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)無(wu)水,應(ying)根(gen)(gen)據(ju)不(bu)同(tong)(tong)(tong)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)來干(gan)燥(zao)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)。做化(hua)(hua)學(xue)分析(xi)(xi)要(yao)(yao)(yao)(yao)(yao)用(yong)(yong)(yong)到(dao)的(de)玻璃(li)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi),應(ying)在(zai)每次實(shi)驗(yan)(yan)完(wan)(wan)畢之(zhi)后(hou)(hou)(hou)洗(xi)凈(jing)(jing)干(gan)燥(zao)備(bei)(bei)(bei)用(yong)(yong)(yong)。用(yong)(yong)(yong)于不(bu)同(tong)(tong)(tong)實(shi)驗(yan)(yan)的(de)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)對干(gan)燥(zao)有(you)(you)(you)不(bu)同(tong)(tong)(tong)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu),一般定(ding)(ding)量(liang)分析(xi)(xi)中的(de)燒(shao)杯(bei)、錐形瓶(ping)等(deng)(deng)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)洗(xi)凈(jing)(jing)即可(ke)使用(yong)(yong)(yong),而用(yong)(yong)(yong)于有(you)(you)(you)機(ji)化(hua)(hua)學(xue)實(shi)驗(yan)(yan)或(huo)有(you)(you)(you)機(ji)分析(xi)(xi)的(de)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)很多是(shi)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)干(gan)燥(zao)的(de),有(you)(you)(you)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)無(wu)水跡,有(you)(you)(you)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)無(wu)水,應(ying)根(gen)(gen)據(ju)不(bu)同(tong)(tong)(tong)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)來干(gan)燥(zao)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)。做化(hua)(hua)學(xue)分析(xi)(xi)要(yao)(yao)(yao)(yao)(yao)用(yong)(yong)(yong)到(dao)的(de)玻璃(li)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi),應(ying)在(zai)每次實(shi)驗(yan)(yan)完(wan)(wan)畢之(zhi)后(hou)(hou)(hou)洗(xi)凈(jing)(jing)干(gan)燥(zao)備(bei)(bei)(bei)用(yong)(yong)(yong)。用(yong)(yong)(yong)于不(bu)同(tong)(tong)(tong)實(shi)驗(yan)(yan)的(de)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)對干(gan)燥(zao)有(you)(you)(you)不(bu)同(tong)(tong)(tong)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu),一般定(ding)(ding)量(liang)分析(xi)(xi)中的(de)燒(shao)杯(bei)、錐形瓶(ping)等(deng)(deng)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)洗(xi)凈(jing)(jing)即可(ke)使用(yong)(yong)(yong),而用(yong)(yong)(yong)于有(you)(you)(you)機(ji)化(hua)(hua)學(xue)實(shi)驗(yan)(yan)或(huo)有(you)(you)(you)機(ji)分析(xi)(xi)的(de)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)很多是(shi)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)干(gan)燥(zao)的(de),有(you)(you)(you)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)無(wu)水跡,有(you)(you)(you)的(de)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)無(wu)水,應(ying)根(gen)(gen)據(ju)不(bu)同(tong)(tong)(tong)要(yao)(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)來干(gan)燥(zao)儀(yi)(yi)(yi)器(qi)(qi)(qi)(qi)(qi)。