一:柱子可以分為:加壓,常壓,減壓
1.yalikeyizengjialinxijideliudongsudu,jianshaochanpinshoujideshijian,danshihuijiandizhuzidetabanshu。suoyiqitatiaojianxiangtongdeshihou,changyazhushixiaolvzuigaode,danshishijianyezuichang,birutianranhuahewudefenli,yigezhuzijigeyueyeshiyoude。
2.減壓柱能夠減少矽膠的使用量,感覺能夠節省一半甚至更多,但是由於大量的空氣通過矽膠會使溶劑揮發(有時在柱子外麵有水汽凝結),以及有些比較易分解的東西可能得不到,而且還必須同時使用水泵抽氣(很大的噪音,而且時間長)。以前曾經大量的過減壓柱,對它有比較深厚的感情,但是自從嚐試了加壓後,就幾乎再也沒動過減壓的念頭了。
3.加壓柱是一種比較好的方法,與常壓柱類似,隻不過外加壓力使淋洗劑走的快些。壓力的提供可以是壓縮空氣,雙連球或者小氣泵(給魚缸供氣的就行)。tebieshizairongyifenjiedeyangpindefenlizhongshiyong。yalibukeguoda,buranrongjizoudetaikuaijiuhuijiandifenlixiaoguo。gerenjiaodejiayazhuzaiputongdeyoujihuahewudefenlizhongshibijiaoshiyongde。
二:關於柱子的尺寸
應該是粗長的最好。柱子長了,相應的塔板數就高。柱子粗了,上樣後樣品的原點就小(反映在柱子上就是樣品層比較薄),這zhe樣yang相xiang對dui的de減jian小xiao了le分fen離li的de難nan度du。試shi想xiang如ru果guo柱zhu子zi十shi厘li米mi,而er樣yang品pin就jiu有you二er厘li米mi,那na麼me分fen離li的de難nan度du可ke想xiang而er知zhi,恐kong怕pa要yao用yong很hen低di極ji性xing的de溶rong劑ji慢man慢man衝chong了le。而er如ru果guo樣yang品pin層ceng隻zhi有you0.5limi,namegezufenjiubijiaorongyidedaowanquanfenlile。dangrancaiyongcudadezhuziyaoxishengbijiaoduodeguijiaoherongjile,buguozhexiechengbenxiangduiyuchanpinlaishuoyexujiubusuanshenmele(有些不環保的說,不過溶劑回收重蒸後也就減小了部分浪費)。
現在見到的柱子徑高比一般在1:5~10,書中寫矽膠量是樣品量的30~40倍,具體的選擇要具體分析。如果所需組分和雜質分的比較開(是指在所需組分rf在0.2~0.4,雜質相差0.1以上),就可以少用矽膠,用小柱子(例如200毫克的樣品,用2cm×20cm的柱子);如果相差不到0.1,就要加大柱子,我覺得可以增加柱子的直徑,比如用3cm的,也可以減小淋洗劑的極性等等。
三:關於無水無氧柱
適shi用yong於yu對dui氧yang,水shui敏min感gan,易yi分fen解jie的de產chan品pin,可ke以yi濕shi柱zhu,也ye可ke以yi幹gan柱zhu。不bu過guo在zai樣yang品pin之zhi前qian至zhi少shao要yao用yong溶rong劑ji把ba柱zhu子zi飽bao和he一yi次ci,因yin為wei溶rong劑ji和he矽gui膠jiao飽bao和he時shi放fang出chu的de熱re量liang有you可ke能neng是shi產chan品pin分fen解jie,畢bi竟jing要yao分fen離li的de是shi敏min感gan的de東dong東dong,小xiao心xin不bu為wei過guo。也ye是shi因yin為wei分fen離li的de東dong西xi比bi較jiao敏min感gan,所suo以yi接jie收shou瓶ping一yi定ding要yao用yong可ke密mi封feng的de,遵zun循xunschlenk操作。至於是加壓、常壓、減壓,隨需而定。因為是schlenk操作,所以點板是個問題,如果樣品是顯色的,恭喜了,不用點板,直接看柱子上的色帶就行了。如果樣品無色,隻好準備幾十個schlenk瓶,一瓶一瓶的點,不過幾次之後就知道樣品在哪,也就可以省些了。像我以前過一根無水無氧柱,需要六個schlenk,xianzaizhiyigejiunengbasuoyaodequanshoujidao。wushuiwuyangzhuzhongyongdebijiaoduodeshiyongyanghualvzuogudingxiang。yinweiguijiaozhongyoudaliangdeqiangjiluoluzaiwai,henrongyishiyangpinfenjie,tebieshijinshuyoujihuahewuhehanlinhuahewu。eryanghualvkeyizuochengjianxing、中性和酸性的,選擇餘地比較大,但是比矽膠要貴些。聽說有個方法,就是用石英做柱子,然後用HF254做固定相,這樣在柱子外麵用紫外燈一照就知道產品在哪裏了,沒有驗證過。哪位做過可以提出來大家參詳參詳。
四:關於濕法、幹法上樣
濕法省事,一般用淋洗劑溶解樣品,也可以用二氯甲烷、乙(yi)酸(suan)乙(yi)酯(zhi)等(deng),但(dan)溶(rong)劑(ji)越(yue)少(shao)越(yue)好(hao),不(bu)然(ran)溶(rong)劑(ji)就(jiu)成(cheng)了(le)淋(lin)洗(xi)劑(ji)了(le)。很(hen)多(duo)樣(yang)品(pin)在(zai)上(shang)柱(zhu)前(qian)是(shi)粘(zhan)乎(hu)乎(hu)的(de),一(yi)般(ban)沒(mei)關(guan)係(xi)。可(ke)是(shi)有(you)的(de)上(shang)樣(yang)後(hou)在(zai)矽(gui)膠(jiao)上(shang)又(you)會(hui)析(xi)出(chu),這(zhe)一(yi)般(ban)都(dou)是(shi)比(bi)較(jiao)大(da)量(liang)的(de)樣(yang)品(pin)才(cai)會(hui)出(chu)現(xian),是(shi)因(yin)為(wei)矽(gui)膠(jiao)對(dui)樣(yang)品(pin)的(de)吸(xi)附(fu)飽(bao)和(he),而(er)樣(yang)品(pin)本(ben)身(shen)又(you)是(shi)比(bi)較(jiao)好(hao)的(de)固(gu)體(ti)才(cai)會(hui)發(fa)生(sheng),這(zhe)就(jiu)應(ying)該(gai)先(xian)重(zhong)結(jie)晶(jing),得(de)到(dao)大(da)部(bu)分(fen)的(de)產(chan)品(pin)後(hou)再(zai)柱(zhu)分(fen),如(ru)果(guo)不(bu)能(neng)重(zhong)結(jie)晶(jing),那(na)就(jiu)不(bu)管(guan)它(ta)了(le),直(zhi)接(jie)過(guo)就(jiu)是(shi)了(le),樣(yang)品(pin)隨(sui)著(zhe)淋(lin)洗(xi)劑(ji)流(liu)動(dong)會(hui)溶(rong)解(jie)的(de)。有(you)些(xie)樣(yang)品(pin)溶(rong)解(jie)性(xing)差(cha),能(neng)溶(rong)解(jie)的(de)溶(rong)劑(ji)又(you)不(bu)能(neng)上(shang)柱(zhu)(比如DMF,DMSO等,會隨著溶劑一起走,顯色是一個很長的脫尾),這時就必須用幹法上柱了。樣品和矽膠的量有一種說法是1:1,我覺得是越少越好,但是要保證在旋幹後,不能看到明顯的固體顆粒(那說明有的樣品沒有吸附在矽膠上)。
五:溶劑的選擇
dangranshizuibianyi,zuianquan,zuihuanbaodele。suoyidaduoxuanyongshiyoumi,yisuanyizhi。wenxianzhongyouxieyongzhengjiwande,taiguile,chufeitebiexuyaobuyaoyongburanyinzihuahuade,liudebilinxijihaikuai,buguoyinweijixinghenxiao,youshihaishifeitabuke。yimiyekeyiyong,danshijiushirongyishuijiao,zhuyibaochiqingxingbierangrongjiliuganle,nayangzhuziyejiubushuangle。erlvjiawanyeyouyongde,danshiyaozhidao,taheguijiaodexifushiyigefangreguocheng,suoyixiatiandeshihoujingchanghuizaizhuzilichanshengqipao,tianqilengdeshihouhuihaoyixie。jiachunjushuonengrongjiebufendeguijiao,suoyichanpinruguoxiangguoyuansufenxidehuayaoliushen,yinggaijingguohoujichuli,birushuozhongjiejingdeng。qitaderongjiyongdexiangduijiaoshao,yaoyigerendebutongxuyaoxuanzele。youyumouxieyuanyin,yongdaodelinxijiduoshidabaozhuangde(便宜嘛),我們這裏是用10升或25shengdesuliaotongzhuangde,jiuyaozhuyizhexiegongyepindechundushijiaodide。jingchangnenggoucongsonglaidedatongdibukanjianyousedezazhi,qitadezazhijiukexiangerzhile,suoyizaibijiaoyangedezhufenshijiuyaoduirongjizhongzheng。dangranguoyuanliaoshijiukeyimianquzheyibule,fanzhengxiamianhaiyoutichundefangfa。
lingwairongjizaiguozhuzihouzuihaoyehuishoushiyong,yifangmianhuanbao,lingyifangmianyenengjieshengbufenjingfei,quedianshiyaoxiaohaoyidingderengong。zheliyaozhuyideshi,yibanzaiguozhutongshijinxingdeshijianyaxuanzheng,shiyoumiheyisuanyizhidebiliyouyuhuifadudebutonghuidaozhijixingdebianhua,yibanhuishidejixingbianda,zaitidulinxishibijiaoheshi,zhenghaojixingyuelaiyuedale。zaiguowanzhuzihou,rongjizuihouhuishouyaocaiyongchangya,yinweizaijianyaxuanzhengshihuiyoubufendifeidiandezazhiyiqichulai,changyashijiuhuijianshaozhezhongxianxiang,ruguozazhihenixiamianyaoguodeyangpinyoufanyingnajiucanle。
六:關於操作問題
1、裝柱:柱zhu子zi下xia麵mian的de活huo塞sai一yi定ding不bu要yao塗tu潤run滑hua劑ji,會hui被bei淋lin洗xi劑ji帶dai到dao產chan品pin中zhong的de,可ke以yi采cai用yong四si氟fu節jie門men的de。幹gan法fa和he濕shi法fa裝zhuang柱zhu覺jiao得de沒mei什shen麼me區qu別bie,隻zhi要yao能neng把ba柱zhu子zi裝zhuang實shi就jiu行xing。裝zhuang完wan的de柱zhu子zi應ying該gai要yao適shi度du的de緊jin密mi(太密了淋洗劑走的太慢),一定要均勻(不然樣品就會從一側斜著下來)。書(shu)中(zhong)寫(xie)的(de)都(dou)是(shi)不(bu)能(neng)見(jian)到(dao)氣(qi)泡(pao),我(wo)覺(jiao)得(de)在(zai)大(da)多(duo)數(shu)情(qing)況(kuang)下(xia)有(you)些(xie)小(xiao)氣(qi)泡(pao)沒(mei)太(tai)大(da)的(de)影(ying)響(xiang),一(yi)加(jia)壓(ya)氣(qi)泡(pao)就(jiu)全(quan)下(xia)來(lai)了(le)。當(dang)然(ran)如(ru)果(guo)你(ni)裝(zhuang)的(de)柱(zhu)子(zi)總(zong)是(shi)有(you)氣(qi)泡(pao)就(jiu)說(shuo)明(ming)需(xu)要(yao)多(duo)練(lian)習(xi)了(le)。但(dan)是(shi)柱(zhu)子(zi)更(geng)忌(ji)諱(hui)的(de)是(shi)開(kai)裂(lie),甭(beng)管(guan)豎(shu)的(de)還(hai)是(shi)橫(heng)的(de),都(dou)會(hui)影(ying)響(xiang)分(fen)離(li)效(xiao)果(guo),甚(shen)至(zhi)作(zuo)廢(fei)!
2、加樣:用yong少shao量liang的de溶rong劑ji溶rong樣yang品pin加jia樣yang,加jia完wan後hou將jiang下xia麵mian的de活huo塞sai打da開kai,待dai溶rong劑ji層ceng下xia降jiang至zhi石shi英ying砂sha麵mian時shi,再zai加jia少shao量liang的de低di極ji性xing溶rong劑ji,然ran後hou再zai打da開kai活huo塞sai,如ru此ci兩liang三san次ci,一yi般ban石shi英ying砂sha就jiu基ji本ben是shi白bai色se的de了le。加jia入ru淋lin洗xi劑ji,一yi開kai始shi不bu要yao加jia壓ya,等deng溶rong樣yang品pin的de溶rong劑ji和he樣yang品pin層ceng有you一yi段duan距ju離li(2~4cm就夠了),再加壓,這樣避免了溶劑(如二氯甲烷等)夾帶樣品快速下行。
3、淋洗劑的選擇:感覺上要使所需點在rf0.2~0.3左右的比較好。不要認為在板上爬高了分的比較開,過柱子就用那種極性,如果rf在0.6,即使相差0.2也不容易在柱子上分開,因為柱子是一個多次爬板的狀態,可以通過公式的比較:0.6/0.8一次的分離度,肯定不如(0.2/0.3)的三次方或四次方大。
4、樣品的收集:yongguijiaozuogudingxiangguozhuzideyuanlishiyigexifuyujiexidepingheng。suoyiruguoyangpinyuguijiaodexifubijiaoqiangdehua,jiuburongyiliuchu。zheyangjiuhuifasheng,houmiandedianxianchu,erqianmiandedianhouchu。zheshikeyicaiyongyanghualvzuogudingxiang。lingwai,shoujideshiguandaxiaoyaoyiyangpinliangerding,tebieshixiaoliangyangpin,ruguoyongdashiguan,kenengyigenjiushoudaolesangeyangpin,wuwu。如果都用小試管那工作量又太大。
5、最後的處理:柱(zhu)分(fen)後(hou)的(de)產(chan)品(pin),由(you)於(yu)使(shi)用(yong)了(le)大(da)量(liang)的(de)溶(rong)劑(ji),其(qi)中(zhong)的(de)雜(za)質(zhi)也(ye)會(hui)累(lei)積(ji)到(dao)產(chan)品(pin)中(zhong),所(suo)以(yi)如(ru)果(guo)想(xiang)送(song)分(fen)析(xi),最(zui)好(hao)用(yong)少(shao)量(liang)的(de)溶(rong)劑(ji)洗(xi)滌(di)一(yi)下(xia),因(yin)為(wei)大(da)部(bu)分(fen)的(de)雜(za)質(zhi)是(shi)溶(rong)在(zai)溶(rong)劑(ji)裏(li)的(de),一(yi)洗(xi)基(ji)本(ben)就(jiu)沒(mei)了(le),必(bi)要(yao)時(shi)進(jin)行(xing)重(zhong)結(jie)晶(jing)。
另外,再過柱的時候,有時會出現氣泡,一是和使用的溶劑有關,如果是易揮發的溶劑,如乙醚、二(er)氯(lv)甲(jia)烷(wan)等(deng),在(zai)室(shi)溫(wen)稍(shao)高(gao)的(de)情(qing)況(kuang)下(xia),很(hen)容(rong)易(yi)出(chu)現(xian)這(zhe)種(zhong)現(xian)象(xiang),因(yin)此(ci),在(zai)室(shi)溫(wen)高(gao)的(de)時(shi)候(hou),可(ke)以(yi)選(xuan)擇(ze)沸(fei)點(dian)較(jiao)高(gao),揮(hui)發(fa)相(xiang)對(dui)小(xiao)的(de)溶(rong)劑(ji)。還(hai)有(you),使(shi)用(yong)混(hun)合(he)溶(rong)劑(ji)時(shi),使(shi)用(yong)的(de)兩(liang)種(zhong)溶(rong)劑(ji)的(de)沸(fei)點(dian)應(ying)該(gai)相(xiang)差(cha)不(bu)大(da),如(ru):乙酸乙酯和石油醚(60~90),而乙醚卻要選擇30-60的石油醚。二是:不論是用帶砂板的還是塞棉花的,在裝柱之前,都要將空氣用加壓的方法將空氣排幹,這樣就可避免柱中有空氣!過柱子需要耐心,不要著急.
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