做化學分析(xi)要用(yong)(yong)到的(de)玻璃儀(yi)器,應在每(mei)次實驗完畢之(zhi)后洗凈干燥備用(yong)(yong)。用(yong)(yong)于(yu)不同(tong)實驗的(de)儀(yi)器對干燥有(you)不同(tong)的(de)要求(qiu),一(yi)般定量分析(xi)中的(de)燒杯、錐形瓶等儀(yi)器洗凈即可使用(yong)(yong),而用(yong)(yong)于(yu)有(you)機(ji)化學實驗或有(you)機(ji)分析(xi)的(de)儀(yi)器很(hen)多是要求(qiu)干燥的(de),有(you)的(de)要求(qiu)無水跡,有(you)的(de)要求(qiu)無水,應根(gen)據(ju)不同(tong)要求(qiu)來(lai)干燥儀(yi)器。
玻璃儀器的潔凈標準
在化學實(shi)(shi)驗時,為避免雜質(zhi)進入反應(ying)體系,影響反應(ying)條件及實(shi)(shi)驗現象的觀察,必須(xu)使用清(qing)潔的玻璃儀(yi)器(qi)。儀(yi)器(qi)的清(qing)洗應(ying)在每(mei)次實(shi)(shi)驗之后立即進行。這是(shi)因為一(yi)方(fang)面清(qing)楚(chu)當(dang)時污物的性質(zhi),以便采取合(he)適的方(fang)式清(qing)除;另一(yi)方(fang)面也(ye)為下一(yi)次實(shi)(shi)驗做好準備。
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)(ruo)要求潔凈(jing)(jing)程度很高時(shi),還(huan)需用(yong)少量蒸餾水(shui)(shui)淋洗二至三次。一個(ge)洗凈(jing)(jing)的(de)玻璃儀(yi)器其瓶壁(bi)上應(ying)不(bu)掛水(shui)(shui)珠,若(ruo)(ruo)有(you)水(shui)(shui)珠時(shi),需重(zhong)新洗滌(di)(di)。應(ying)該指出的(de)是,洗滌(di)(di)后(hou)的(de)儀(yi)器不(bu)能用(yong)抹布(bu)、濾紙等擦干。有(you)些反應(ying)殘余物用(yong)去污粉(fen)不(bu)易洗凈(jing)(jing),可根(gen)據污物的(de)具體情況采(cai)用(yong)價格較低或(huo)回(hui)收(shou)的(de)有(you)機溶(rong)劑(ji)(ji)浸(jin)泡或(huo)用(yong)稀酸、堿液來(lai)清(qing)洗,但不(bu)能盲目使用(yong),以(yi)免造成(cheng)浪費(fei)和(he)事故(例如,殘留浪的(de)儀(yi)器,若(ruo)(ruo)用(yong)丙酮清(qing)洗將會產生(sheng)強力(li)催淚劑(ji)(ji)——溴化丙酮)。儀(yi)器壁(bi)上的(de)陳跡可以(yi)采(cai)用(yong)洗液浸(jin)泡后(hou)清(qing)洗除(chu)去。
洗滌禁忌須知
1.常(chang)法洗(xi)滌儀(yi)器(qi)(qi)。洗(xi)刷儀(yi)器(qi)(qi)時,應首先(xian)將手用肥(fei)皂洗(xi)凈,免得手上的(de)油污附在儀(yi)器(qi)(qi)上,增加洗(xi)刷的(de)困難。如儀(yi)器(qi)(qi)長久存放(fang)附有塵(chen)灰,先(xian)用清水沖(chong)去,再按(an)要求選(xuan)用潔凈劑(ji)洗(xi)刷或洗(xi)滌。用蒸餾水沖(chong)洗(xi)時,要用順壁沖(chong)洗(xi)方法并充分震蕩,經蒸餾水沖(chong)洗(xi)后的(de)儀(yi)器(qi)(qi),用指示劑(ji)檢(jian)查應為中性(xing)。
2.作痕量金(jin)屬分(fen)析的玻璃儀(yi)器,使用1:1~1:9HNO3溶液浸泡,然后進行常法洗滌。
3.進(jin)行熒(ying)光分(fen)析時,玻璃儀器應(ying)避免使用洗衣(yi)粉(fen)洗滌(因洗衣(yi)粉(fen)中含有熒(ying)光增白劑,會給(gei)分(fen)析結(jie)果帶來誤(wu)差)。
4.分(fen)析致癌物質時,應選用適(shi)當洗(xi)消夜(ye)浸泡(pao),然(ran)后再按常法洗(xi)滌(di)。
常見干燥方式
進(jin)行(xing)化(hua)學(xue)實驗所使用(yong)的(de)(de)儀器(qi)(qi)(qi)除了需(xu)(xu)(xu)要清洗外常常還需(xu)(xu)(xu)要干燥(zao)。水(shui)的(de)(de)存在(zai)有(you)時(shi)會影響化(hua)學(xue)反應(ying)的(de)(de)速度或(huo)(huo)產率,有(you)時(shi)甚至使化(hua)學(xue)反應(ying)無法(fa)進(jin)行(xing)。對(dui)于一般無水(shui)要求(qiu)的(de)(de)實驗,只需(xu)(xu)(xu)將儀器(qi)(qi)(qi)倒置晾干便可使用(yong);而對(dui)于絕(jue)對(dui)無水(shui)的(de)(de)實驗,則需(xu)(xu)(xu)將儀器(qi)(qi)(qi)置烘(hong)箱中(zhong)或(huo)(huo)熱氣(qi)(qi)流烘(hong)干器(qi)(qi)(qi)上烘(hong)干。若需(xu)(xu)(xu)急(ji)用(yong),可將洗凈的(de)(de)儀器(qi)(qi)(qi)用(yong)少量(liang)(liang)乙醇(chun)或(huo)(huo)丙酮蕩洗,再用(yong)吹風(feng)機吹干。必(bi)須特(te)別(bie)指(zhi)出的(de)(de)是(shi),無論用(yong)何(he)種方法(fa)干燥(zao)的(de)(de)儀器(qi)(qi)(qi),都(dou)必(bi)須讓儀器(qi)(qi)(qi)冷(leng)至室溫(wen)時(shi)才能(neng)取(qu)出,否則熱的(de)(de)儀器(qi)(qi)(qi)驟(zou)冷(leng)時(shi),水(shui)氣(qi)(qi)將在(zai)器(qi)(qi)(qi)壁上凝聚。只要不是(shi)容量(liang)(liang)儀器(qi)(qi)(qi)(量(liang)(liang)筒、滴定管、移液管等)都(dou)可以烘(hong)干。
1.晾(liang)干
不急用(yong)的,要求(qiu)一般干燥(zao),可在純水涮洗(xi)后,在無(wu)塵處倒置(zhi)晾干水分,然后自(zi)然干燥(zao)。可用(yong)安有斜木(mu)釘的架(jia)子和帶有透氣(qi)孔(kong)的玻璃柜放置(zhi)儀器。
2.烘干
洗凈的(de)儀器(qi)控(kong)去水分,放在電烘箱中烘干,烘箱溫度為105~120℃烘1h左右。也可放在紅外燈干燥(zao)箱中烘干。此法適用于一般儀器(qi)。稱量用的(de)稱量瓶等烘干后(hou)要(yao)(yao)放在干燥(zao)器(qi)中冷卻和保存。帶實心玻璃塞的(de)及(ji)厚壁儀器(qi)烘干時(shi)要(yao)(yao)注(zhu)意慢(man)慢(man)升溫并且溫度不(bu)可過高,以免烘裂,量器(qi)不(bu)可放于烘箱中烘。硬質試(shi)管(guan)可用酒精燈烘干,要(yao)(yao)從底(di)部烘起,把試(shi)管(guan)口向(xiang)下,以免水珠倒流把試(shi)管(guan)炸裂,烘到無水珠時(shi),把試(shi)管(guan)口向(xiang)上趕凈水汽。
3.熱(冷)風吹(chui)干(gan)
元(yuan)素分析儀對于急于干(gan)燥的(de)(de)儀器(qi)或(huo)不(bu)適合放入烘箱的(de)(de)較大的(de)(de)儀器(qi)可用吹干(gan)的(de)(de)辦(ban)法,通常用少量乙(yi)(yi)醇、丙酮(或(huo)最后(hou)再(zai)(zai)用乙(yi)(yi)醚)倒入已控去水分的(de)(de)儀器(qi)中(zhong)搖(yao)洗控凈溶劑(溶劑要回收),然后(hou)用電吹風(feng)(feng)(feng)吹,開(kai)始用冷風(feng)(feng)(feng)吹1~2min,當大部(bu)分溶劑揮發后(hou)吹入熱風(feng)(feng)(feng)至完(wan)全干(gan)燥,再(zai)(zai)用冷風(feng)(feng)(feng)吹殘余的(de)(de)蒸汽,使其不(bu)再(zai)(zai)冷凝(ning)在容器(qi)內。此法要求通風(feng)(feng)(feng)好,防止中(zhong)毒,不(bu)可接觸(chu)明(ming)火,以防有機溶劑爆炸(zha)。
烘箱中烘干應注意什么?
準確的說玻璃儀器(qi)都不能放(fang)(fang)入(ru)烘(hong)箱中烘(hong)干(gan),能放(fang)(fang)入(ru)的玻璃器(qi)具其作用(yong)是(shi)用(yong)于盛放(fang)(fang)而不是(shi)測(ce)量(liang)用(yong)的。比(bi)如,燒(shao)杯、燒(shao)瓶(ping)、圓底(di)燒(shao)瓶(ping)適(shi)合(he)烘(hong)干(gan),玻璃制品的量(liang)具類(帶有刻度)滴定管(guan)、移(yi)液(ye)管(guan)、量(liang)筒不適(shi)合(he)烘(hong)干(gan)。
烘干(gan)玻(bo)(bo)璃(li)容易(yi)溫度不(bu)(bu)可(ke)過高(gao),做(zuo)好是100度以下(xia),取出(chu)時注意帶耐高(gao)溫手(shou)套,防止燙傷,另外,最好將烘箱溫度到(dao)達(da)45度以下(xia)(或(huo)者(zhe)常溫)再取出(chu)儀(yi)(yi)器(qi)(qi)(qi),高(gao)溫下(xia)不(bu)(bu)可(ke)取出(chu),防止驟冷驟熱導(dao)致玻(bo)(bo)璃(li)碎裂(lie)。做(zuo)化(hua)學分(fen)(fen)析(xi)(xi)(xi)(xi)要(yao)(yao)(yao)(yao)用(yong)(yong)(yong)到(dao)的(de)(de)(de)(de)(de)(de)玻(bo)(bo)璃(li)儀(yi)(yi)器(qi)(qi)(qi),應(ying)(ying)在(zai)每次(ci)實(shi)(shi)(shi)驗(yan)(yan)完畢(bi)之(zhi)后洗(xi)(xi)(xi)(xi)凈干(gan)燥(zao)(zao)備(bei)用(yong)(yong)(yong)。用(yong)(yong)(yong)于(yu)不(bu)(bu)同(tong)(tong)(tong)實(shi)(shi)(shi)驗(yan)(yan)的(de)(de)(de)(de)(de)(de)儀(yi)(yi)器(qi)(qi)(qi)對(dui)干(gan)燥(zao)(zao)有(you)(you)不(bu)(bu)同(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu),一(yi)般定(ding)量分(fen)(fen)析(xi)(xi)(xi)(xi)中(zhong)的(de)(de)(de)(de)(de)(de)燒杯(bei)、錐(zhui)形(xing)瓶等儀(yi)(yi)器(qi)(qi)(qi)洗(xi)(xi)(xi)(xi)凈即(ji)(ji)可(ke)使用(yong)(yong)(yong),而(er)用(yong)(yong)(yong)于(yu)有(you)(you)機(ji)(ji)化(hua)學實(shi)(shi)(shi)驗(yan)(yan)或(huo)有(you)(you)機(ji)(ji)分(fen)(fen)析(xi)(xi)(xi)(xi)的(de)(de)(de)(de)(de)(de)儀(yi)(yi)器(qi)(qi)(qi)很多是要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)干(gan)燥(zao)(zao)的(de)(de)(de)(de)(de)(de),有(you)(you)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)無水(shui)跡,有(you)(you)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)無水(shui),應(ying)(ying)根據不(bu)(bu)同(tong)(tong)(tong)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)來干(gan)燥(zao)(zao)儀(yi)(yi)器(qi)(qi)(qi)。做(zuo)化(hua)學分(fen)(fen)析(xi)(xi)(xi)(xi)要(yao)(yao)(yao)(yao)用(yong)(yong)(yong)到(dao)的(de)(de)(de)(de)(de)(de)玻(bo)(bo)璃(li)儀(yi)(yi)器(qi)(qi)(qi),應(ying)(ying)在(zai)每次(ci)實(shi)(shi)(shi)驗(yan)(yan)完畢(bi)之(zhi)后洗(xi)(xi)(xi)(xi)凈干(gan)燥(zao)(zao)備(bei)用(yong)(yong)(yong)。用(yong)(yong)(yong)于(yu)不(bu)(bu)同(tong)(tong)(tong)實(shi)(shi)(shi)驗(yan)(yan)的(de)(de)(de)(de)(de)(de)儀(yi)(yi)器(qi)(qi)(qi)對(dui)干(gan)燥(zao)(zao)有(you)(you)不(bu)(bu)同(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu),一(yi)般定(ding)量分(fen)(fen)析(xi)(xi)(xi)(xi)中(zhong)的(de)(de)(de)(de)(de)(de)燒杯(bei)、錐(zhui)形(xing)瓶等儀(yi)(yi)器(qi)(qi)(qi)洗(xi)(xi)(xi)(xi)凈即(ji)(ji)可(ke)使用(yong)(yong)(yong),而(er)用(yong)(yong)(yong)于(yu)有(you)(you)機(ji)(ji)化(hua)學實(shi)(shi)(shi)驗(yan)(yan)或(huo)有(you)(you)機(ji)(ji)分(fen)(fen)析(xi)(xi)(xi)(xi)的(de)(de)(de)(de)(de)(de)儀(yi)(yi)器(qi)(qi)(qi)很多是要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)干(gan)燥(zao)(zao)的(de)(de)(de)(de)(de)(de),有(you)(you)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)無水(shui)跡,有(you)(you)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)無水(shui),應(ying)(ying)根據不(bu)(bu)同(tong)(tong)(tong)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)來干(gan)燥(zao)(zao)儀(yi)(yi)器(qi)(qi)(qi)。做(zuo)化(hua)學分(fen)(fen)析(xi)(xi)(xi)(xi)要(yao)(yao)(yao)(yao)用(yong)(yong)(yong)到(dao)的(de)(de)(de)(de)(de)(de)玻(bo)(bo)璃(li)儀(yi)(yi)器(qi)(qi)(qi),應(ying)(ying)在(zai)每次(ci)實(shi)(shi)(shi)驗(yan)(yan)完畢(bi)之(zhi)后洗(xi)(xi)(xi)(xi)凈干(gan)燥(zao)(zao)備(bei)用(yong)(yong)(yong)。用(yong)(yong)(yong)于(yu)不(bu)(bu)同(tong)(tong)(tong)實(shi)(shi)(shi)驗(yan)(yan)的(de)(de)(de)(de)(de)(de)儀(yi)(yi)器(qi)(qi)(qi)對(dui)干(gan)燥(zao)(zao)有(you)(you)不(bu)(bu)同(tong)(tong)(tong)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu),一(yi)般定(ding)量分(fen)(fen)析(xi)(xi)(xi)(xi)中(zhong)的(de)(de)(de)(de)(de)(de)燒杯(bei)、錐(zhui)形(xing)瓶等儀(yi)(yi)器(qi)(qi)(qi)洗(xi)(xi)(xi)(xi)凈即(ji)(ji)可(ke)使用(yong)(yong)(yong),而(er)用(yong)(yong)(yong)于(yu)有(you)(you)機(ji)(ji)化(hua)學實(shi)(shi)(shi)驗(yan)(yan)或(huo)有(you)(you)機(ji)(ji)分(fen)(fen)析(xi)(xi)(xi)(xi)的(de)(de)(de)(de)(de)(de)儀(yi)(yi)器(qi)(qi)(qi)很多是要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)干(gan)燥(zao)(zao)的(de)(de)(de)(de)(de)(de),有(you)(you)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)無水(shui)跡,有(you)(you)的(de)(de)(de)(de)(de)(de)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)無水(shui),應(ying)(ying)根據不(bu)(bu)同(tong)(tong)(tong)要(yao)(yao)(yao)(yao)求(qiu)(qiu)(qiu)(qiu)(qiu)來干(gan)燥(zao)(zao)儀(yi)(yi)器(qi)(qi)(qi)。