高效液相色譜儀(HPLC)是shi分fen析xi實shi驗yan室shi常chang用yong的de測ce試shi儀yi器qi之zhi一yi,其qi應ying用yong越yue來lai越yue廣guang泛fan。此ci種zhong儀yi器qi在zai使shi用yong過guo程cheng中zhong,難nan免mian會hui出chu現xian各ge種zhong各ge樣yang的de問wen題ti,並bing將jiang直zhi接jie影ying響xiang到dao所suo測ce數shu據ju的de準zhun確que性xing和he儀yi器qi的de正zheng常chang工gong作zuo。操cao作zuo者zhe如ru果guo能neng了le解jie故gu障zhang的de成cheng因yin,即ji可ke清qing楚chu預yu防fang和he排pai除chu這zhe些xie故gu障zhang的de方fang法fa,就jiu可ke正zheng確que地di使shi用yong儀yi器qi並bing最zui大da限xian度du地di發fa揮hui儀yi器qi的de性xing能neng。今jin天tian我wo們men要yao從cong以yi下xia幾ji個ge方fang麵mian分fen享xiang下xia在zai使shi用yong高gao效xiao液ye相xiang色se譜pu儀yi中zhong需xu注zhu意yi的de幾ji個ge問wen題ti。
一、使用試管的問題
1、試管的潔淨問題。gaoxiaoyexiangsepufenxifashiyigehenlingmindefenxifangfa,ruguoyinshiyongbujiejingdeshiguan,bianhuiyingxiangshiyanjieguodezhunquexing。liru,zaiyongjiachunzuorongjilairongjieyangpinshi,suoyongdexiaoshiguanshiyongxiangjiaosailaizuogaizide,yinci,zaimeicijinyangshi,douyouyigebaoliushijiangudingdeganraofengcunzai,houjingzhengshi,ciganraofengshiyoujiachunjinpaoxiangjiaosaierrongxiadezufensuochansheng,huanyongbolishiguanhou,ganraofengxiaochu。
2、塑料試管的溶解問題。近jin年nian來lai,一yi次ci性xing塑su料liao試shi管guan給gei試shi驗yan人ren員yuan帶dai來lai了le極ji大da的de方fang便bian,但dan是shi,在zai使shi用yong過guo程cheng中zhong一yi定ding要yao注zhu意yi有you機ji溶rong劑ji對dui試shi管guan的de溶rong解jie現xian象xiang,在zai利li用yong此ci種zhong試shi管guan提ti取qu樣yang品pin時shi,有you些xie有you機ji溶rong劑ji(如氯仿等)對(dui)管(guan)壁(bi)有(you)溶(rong)解(jie)現(xian)象(xiang),這(zhe)些(xie)被(bei)溶(rong)解(jie)下(xia)來(lai)的(de)物(wu)質(zhi)有(you)時(shi)也(ye)能(neng)在(zai)檢(jian)測(ce)器(qi)上(shang)產(chan)生(sheng)信(xin)號(hao),從(cong)而(er)幹(gan)擾(rao)樣(yang)品(pin)的(de)測(ce)定(ding)。這(zhe)時(shi),可(ke)用(yong)相(xiang)同(tong)的(de)實(shi)驗(yan)條(tiao)件(jian)先(xian)行(xing)試(shi)驗(yan)一(yi)下(xia),看(kan)看(kan)不(bu)含(han)被(bei)抽(chou)提(ti)物(wu)時(shi),提(ti)取(qu)液(ye)在(zai)檢(jian)測(ce)器(qi)上(shang)能(neng)否(fou)產(chan)生(sheng)幹(gan)擾(rao)信(xin)號(hao),如(ru)確(que)有(you)幹(gan)擾(rao)信(xin)號(hao)存(cun)在(zai),就(jiu)隻(zhi)能(neng)換(huan)用(yong)耐(nai)有(you)機(ji)溶(rong)劑(ji)的(de)玻(bo)璃(li)試(shi)管(guan)了(le)。
3、被測樣品在試管壁上的吸附問題。這個問題也應引起注意,否則也會影響測試結果的準確性,在治療藥物監測(Therapeutic Drug Monitoring,TDM)中(zhong),有(you)些(xie)被(bei)測(ce)藥(yao)物(wu)如(ru)阿(e)米(mi)替(ti)林(lin),丙(bing)咪(mi)嗪(qin)等(deng)易(yi)吸(xi)附(fu)在(zai)玻(bo)璃(li)試(shi)管(guan)的(de)管(guan)壁(bi)上(shang),因(yin)此(ci),操(cao)作(zuo)中(zhong)宜(yi)采(cai)用(yong)聚(ju)丙(bing)烯(xi)管(guan),為(wei)防(fang)止(zhi)提(ti)取(qu)中(zhong)吸(xi)附(fu)現(xian)象(xiang)的(de)發(fa)生(sheng),可(ke)采(cai)用(yong)0.5%的已二胺已烷液做為提取劑,可有效地防止吸附。
二、操作進樣閥的問題
目前,在分析型高效液相色譜儀中常用的進樣閥是7725型(xing)進(jin)樣(yang)閥(fa),其(qi)內(nei)部(bu)的(de)六(liu)通(tong)閥(fa)結(jie)構(gou)使(shi)進(jin)樣(yang)操(cao)作(zuo)非(fei)常(chang)方(fang)便(bian),但(dan)是(shi),如(ru)果(guo)使(shi)用(yong)不(bu)當(dang),也(ye)會(hui)帶(dai)來(lai)問(wen)題(ti)。例(li)如(ru),在(zai)高(gao)效(xiao)液(ye)相(xiang)色(se)譜(pu)法(fa)的(de)試(shi)驗(yan)過(guo)程(cheng)中(zhong),有(you)時(shi)會(hui)有(you)異(yi)常(chang)色(se)譜(pu)峰(feng)的(de)出(chu)現(xian)以(yi)及(ji)重(zhong)現(xian)性(xing)不(bu)好(hao)的(de)問(wen)題(ti),這(zhe)主(zhu)要(yao)是(shi)由(you)於(yu)操(cao)作(zuo)方(fang)法(fa)不(bu)當(dang)所(suo)引(yin)起(qi),要(yao)想(xiang)解(jie)決(jue)此(ci)類(lei)問(wen)題(ti),需(xu)從(cong)以(yi)下(xia)幾(ji)個(ge)方(fang)麵(mian)入(ru)手(shou)。
1、進樣量的控製。用進樣閥來進樣時,閥內的樣品環是定量的,(一般分析型進樣閥的樣品環體積為20ul),由於進樣時,注射到進樣閥內的樣品溶液在樣品環的管路中有徑向的速度梯度(即管軸處比管壁處的液流速度快)。因此,要想使樣品環中充滿樣品溶液,從而使用進樣閥來準確地定量,則必須使進樣量大於樣品環體積的2倍。如果用注射器來控製進樣量,則最大隻能注射樣品環體積1/2的量,這樣才能防止部分樣品由溢流管溢出從而導致定量分析的誤差。
2、進樣閥的清潔問題。如果樣品環中有上次進樣時樣品的殘留,必然會汙染下次注射進的樣品,為防止這種現象的發生,應按下列步驟操作:a.進樣閥有2個位置,INJECT和LOAD。首先在LOAD位置時,以注射器將流動相注入進樣閥內清洗幾次,每次用量大約40ul;b.然後將進樣閥板手扳至INJECT位置時,再以流動相清洗幾次,每次用量還是40ul;c.最後,再將樣品注射到進樣閥裏。
按照上述的步驟操作,可以避免由進樣閥引起的汙染,從而使幹擾峰消除並提高分析結果的準確性。
3、進樣閥溢流管的堵塞。有(you)時(shi),進(jin)樣(yang)閥(fa)的(de)溢(yi)流(liu)管(guan)會(hui)發(fa)生(sheng)堵(du)塞(sai)現(xian)象(xiang),向(xiang)進(jin)樣(yang)閥(fa)內(nei)注(zhu)射(she)樣(yang)品(pin)時(shi),注(zhu)射(she)針(zhen)推(tui)不(bu)動(dong)。此(ci)故(gu)障(zhang)是(shi)由(you)於(yu)溢(yi)流(liu)管(guan)的(de)堵(du)塞(sai)所(suo)致(zhi)。堵(du)塞(sai)的(de)原(yuan)因(yin)多(duo)半(ban)是(shi)由(you)於(yu)溶(rong)解(jie)樣(yang)品(pin)的(de)流(liu)動(dong)相(xiang)用(yong)的(de)是(shi)鹽(yan)溶(rong)液(ye),而(er)其(qi)中(zhong)的(de)鹽(yan)在(zai)溢(yi)流(liu)管(guan)的(de)排(pai)空(kong)端(duan)口(kou)處(chu)結(jie)晶(jing)所(suo)致(zhi)。此(ci)時(shi),可(ke)用(yong)小(xiao)燒(shao)杯(bei)盛(sheng)少(shao)量(liang)蒸(zheng)餾(liu)水(shui)對(dui)溢(yi)流(liu)管(guan)口(kou)稍(shao)加(jia)浸(jin)泡(pao),端(duan)口(kou)處(chu)鹽(yan)的(de)結(jie)晶(jing)就(jiu)能(neng)被(bei)溶(rong)解(jie)掉(diao),故(gu)障(zhang)排(pai)除(chu)。如(ru)能(neng)在(zai)每(mei)次(ci)進(jin)樣(yang)完(wan)成(cheng)之(zhi)後(hou),用(yong)蒸(zheng)餾(liu)水(shui)反(fan)複(fu)衝(chong)洗(xi)至(zhi)溢(yi)流(liu)管(guan)中(zhong)的(de)鹽(yan)分(fen)全(quan)部(bu)衝(chong)出(chu),則(ze)可(ke)避(bi)免(mian)此(ci)故(gu)障(zhang)的(de)發(fa)生(sheng)。
三、流動相的問題
甲(jia)醇(chun)和(he)乙(yi)腈(jing)在(zai)高(gao)效(xiao)液(ye)相(xiang)色(se)譜(pu)分(fen)析(xi)法(fa)中(zhong)常(chang)常(chang)被(bei)用(yong)來(lai)配(pei)製(zhi)流(liu)動(dong)相(xiang)。高(gao)效(xiao)液(ye)相(xiang)色(se)譜(pu)法(fa)中(zhong)常(chang)用(yong)的(de)試(shi)劑(ji)最(zui)好(hao)是(shi)高(gao)等(deng)級(ji)的(de)專(zhuan)用(yong)試(shi)劑(ji),如(ru)色(se)譜(pu)純(chun)試(shi)劑(ji)。在(zai)要(yao)求(qiu)不(bu)太(tai)嚴(yan)格(ge)時(shi),優(you)級(ji)純(chun)甚(shen)至(zhi)分(fen)析(xi)純(chun)的(de)試(shi)劑(ji)也(ye)能(neng)用(yong)。高(gao)效(xiao)液(ye)相(xiang)色(se)譜(pu)分(fen)析(xi)法(fa)中(zhong)常(chang)用(yong)的(de)是(shi)紫(zi)外(wai)檢(jian)測(ce)器(qi),因(yin)此(ci),從(cong)降(jiang)低(di)基(ji)線(xian)噪(zao)音(yin)和(he)提(ti)高(gao)分(fen)析(xi)靈(ling)敏(min)度(du)上(shang)來(lai)考(kao)慮(lv),應(ying)該(gai)使(shi)用(yong)紫(zi)外(wai)吸(xi)收(shou)小(xiao)且(qie)雜(za)質(zhi)含(han)量(liang)少(shao)的(de)色(se)譜(pu)純(chun)試(shi)劑(ji)。
1、流動相的過濾。配製好的流動相在使用前一定要先用0.5um孔徑的微孔濾膜來過濾。這是因為溶液中含有很多肉眼難以發現的微小顆粒,如果不把它們濾除掉,就會堵塞泵口、柱zhu頭tou上shang的de過guo濾lv器qi,這zhe樣yang就jiu堵du塞sai了le流liu動dong相xiang的de正zheng常chang通tong道dao,使shi色se譜pu柱zhu的de阻zu力li增zeng加jia,柱zhu壓ya升sheng高gao,柱zhu效xiao下xia降jiang。碰peng到dao這zhe種zhong情qing況kuang時shi,要yao換huan用yong經jing過guo濾lv的de流liu動dong相xiang,並bing將jiang堵du塞sai的de濾lv器qi拆chai下xia來lai浸jin泡pao在zai20%的硝酸水溶液中以超聲波清洗機清洗20分鍾,以除去濾片上的堵塞物。
2、流動相的脫氣。liudongxiangzaishiyongqianbixutuoqi,yijinkenengdechuqurongjiezailiudongxiangzhongdeqiti,fouze,zhexieqitihuishizhutianliaodexingnengjiangdi,hainenggouduijianceqidexinhaochanshenghendadeganrao。tuoqiyouduozhongfangfa,ruchaoshengtuoqi、真空脫氣、danqituoqideng。zhenkongtuoqifahedanqiliutuoqifashimuqianzuichangyongdetuoqifa。shuihejiachunhunhehouhuichanshengdaliangdeqipao,ruguobutuoqijiushiyong,qipaojiuhuijinrusepuzhuhejianceqi,bingjiangyingxiangfenxigongzuodezhengchangjinxing。
四、色譜柱的使用和保養
色譜柱是高效液相色譜儀最主要的部件,beicewuzhinengfoubeihenhaodefenliheceding,sepuzhudexingnengqizhejuedingxingdezuoyong。yinci,zairichanggongzuozhong,yingtebiezhuyisepuzhudezhengqueshiyongheweixiubaoyang,yiyanchangsepuzhudeshiyongshouming。
1、使用預柱和保護柱。預柱(pre-column)安裝於泵和進樣器之間,它給色譜柱中的流動相提供了完全的平衡,並防止了對柱填料有破壞作用的組分或汙染物進入色譜柱。保護柱(guard column)keyizudangnenggoulaogudixifuyusepuzhushangdezufenjinrusepuzhu,baohuzhuyingyusepuzhudetianliaoxiangtong。yuzhuhebaohuzhukeyijingchanggenghuan,erbuxuyaojingchanggenghuansepuzhu,zhejiuyanchanglesepuzhudeshiyongshouming。
2、防止氣體進入色譜柱。有些色譜柱(如凝膠柱)shibuyunxuqipaojinrude,fouzejianghuishizhuxiaojiangdishenzhixingchengweixiaodenanyiquchudeqishi。yinci,weilefangzhiqipaojinrusepuzhu,yidingyaoshiyongjingguotuoqideliudongxiang,bingqieyaoyangeanzhaoxialiebuzhoulaianzhuangsepuzhu。a.拆卸下色譜柱入口處的密封螺絲,觀察是否有溶劑滲出;b.如有溶劑滲出,即可將色譜柱接到管路上,以避免氣泡的進入;c.如ru無wu溶rong劑ji滲shen出chu時shi,表biao明ming色se譜pu柱zhu的de此ci端duan已yi經jing進jin去qu空kong氣qi了le,此ci時shi,可ke將jiang色se譜pu柱zhu的de出chu口kou端duan接jie到dao進jin樣yang閥fa上shang,以yi流liu動dong相xiang來lai反fan方fang向xiang衝chong洗xi色se譜pu柱zhu,以yi便bian將jiang柱zhu內nei的de空kong氣qi排pai除chu。最zui好hao以yi0.2ml/min的小流量來衝色譜柱,如果溶劑的流速太快或者是壓力突然的上升都將會導致柱性能的降低;d.如果流出的溶劑裏不含有氣泡,說明柱內的氣體已經被排出了,再將色譜柱以正確的方向接好,這樣氣泡就進不到色譜柱裏麵了。
3、色譜柱的清洗。weilebushibeicewuzhihezazhitingliuzaisepuzhuzhong,zaimeicideyangpinfenxigongzuowanchengzhihou,douyingjishidiqingxisepuzhu。shouxianyaoyongduibeiceyangpinxituonengliqiangderongjilaixituosepuzhu,yifenxigongzuozhongchangyongdefanxiangsepufenxifaweili,yinqixianliuchudewuzhishijixingdadewuzhi,cishiyingyong100%的甲醇或使用異丙純、四氫呋喃等極性稍弱的溶劑將吸附在柱內的極性小的物質洗脫下來,洗脫液的用量一般為柱體積的20倍即可。如果流動相是緩衝溶液,則應先用蒸餾水來衝洗色譜柱,以衝掉柱內的鹽,然後再用合適的溶劑來衝洗。
凝膠濾過色譜法(Gel Filtration Chromatography)中zhong所suo使shi用yong的de凝ning膠jiao柱zhu常chang用yong緩huan衝chong溶rong液ye做zuo流liu動dong相xiang,用yong完wan之zhi後hou當dang然ran要yao用yong蒸zheng餾liu水shui來lai衝chong洗xi。如ru果guo是shi連lian續xu操cao作zuo,可ke以yi將jiang緩huan衝chong溶rong液ye置zhi於yu柱zhu內nei過guo夜ye,但dan最zui好hao是shi維wei持chi小xiao流liu速su(<0.5ml/min)以防止緩衝鹽的析出,如果流動相中含有鹵化物,即使是停一夜,也必須要用蒸餾水將色譜柱衝洗幹淨,以防止它們對柱體的腐蝕。
4、色譜柱的存放。如果色譜柱暫時不用,存放時要注意以下幾點:
a.幾天之內的短期放置,應先用溶劑衝洗好色譜柱(如凝膠柱則用蒸餾水來衝洗),再把色譜柱的兩頭用密封螺絲密封好即可。
b.如ru果guo色se譜pu柱zhu長chang期qi不bu用yong,僅jin用yong上shang述shu方fang法fa來lai處chu理li就jiu不bu行xing了le,這zhe時shi應ying使shi用yong色se譜pu柱zhu使shi用yong說shuo明ming書shu中zhong所suo指zhi明ming的de溶rong劑ji來lai充chong滿man色se譜pu柱zhu,反fan相xiang柱zhu一yi般ban使shi用yong甲jia醇chun,正zheng相xiang柱zhu則ze可ke用yong正zheng已yi烷wan或huo庚geng烷wan,而er凝ning膠jiao柱zhu則ze不bu能neng用yong水shui了le,因yin柱zhu內nei如ru果guo有you微wei生sheng物wu的de生sheng長chang則ze會hui使shi柱zhu效xiao降jiang低di,此ci時shi應ying用yong0.05%的NaNs水溶液(防腐劑)laichongxisepuzhu,zaijiangsepuzhufengyan。sepuzhuchangqifangzhishi,yidingyaojiangsepuzhudeliangduanfengyan,yifangzhiyouyurongjihuifaerzaochengdezhutianliaogansuoxianxiang,yinzhekedaozhizhuxiaodeyanzhongjiangdi。
c.色譜柱應貯存在室溫下,如果放置於0℃以下的環境裏,柱內就會結冰,這也將導致柱效的降低。
五、色譜峰的雙峰問題
長期使用後的色譜柱,如果有雜質進入,就會使色譜柱入口處的固定相“板結”並(bing)在(zai)流(liu)動(dong)相(xiang)所(suo)產(chan)生(sheng)的(de)高(gao)壓(ya)作(zuo)用(yong)下(xia),形(xing)成(cheng)柱(zhu)頭(tou)的(de)塌(ta)陷(xian),被(bei)分(fen)析(xi)的(de)樣(yang)品(pin)組(zu)分(fen)的(de)正(zheng)常(chang)色(se)譜(pu)峰(feng)就(jiu)變(bian)成(cheng)了(le)雙(shuang)峰(feng),這(zhe)時(shi)可(ke)按(an)下(xia)述(shu)方(fang)法(fa)來(lai)修(xiu)複(fu)色(se)譜(pu)柱(zhu)。首(shou)先(xian)將(jiang)柱(zhu)頭(tou)的(de)緊(jin)固(gu)螺(luo)母(mu)旋(xuan)下(xia),這(zhe)時(shi)就(jiu)會(hui)發(fa)現(xian)柱(zhu)頭(tou)內(nei)的(de)固(gu)定(ding)相(xiang)已(yi)被(bei)壓(ya)縮(suo)進(jin)去(qu)了(le),嚴(yan)重(zhong)時(shi)可(ke)縮(suo)進(jin)10mm以上。在這種情況下,我們可用針尖將流動相表層板結變黃的部分摳掉,並以相同的固定相將此塌陷區填平、壓實,再將色譜柱的緊固螺絲上緊,修複工作即告結束。用經過修複後的色譜柱再做樣品時,色譜峰就恢複正常了。
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