進口(kou)標準(zhun)品配制方法:
將碘(dian)溶(rong)(rong)(rong)(rong)于(yu)吡(bi)啶(ding)中，做為儲(chu)備液(ye)，此溶(rong)(rong)(rong)(rong)液(ye)穩定，于(yu)應用(yong)(yong)(yong)(yong)前，將此溶(rong)(rong)(rong)(rong)液(ye)用(yong)(yong)(yong)(yong)甲(jia)醇(chun)稀釋，并(bing)加(jia)(jia)(jia)入二氧化硫(liu)，使三(san)者(zhe)的(de)(de)摩爾(er)比為： 碘(dian):二氧化硫(liu):吡(bi)啶(ding)=1:3:10 ，并(bing)使每毫升(sheng)試(shi)劑(ji)相當于(yu)2～5毫克水。常用(yong)(yong)(yong)(yong)的(de)(de)配方是84.7克（0.33摩爾(er)）碘(dian)溶(rong)(rong)(rong)(rong)于(yu)269毫升(sheng)（3.3摩爾(er)）無(wu)水吡(bi)啶(ding)中，加(jia)(jia)(jia)667毫升(sheng)無(wu)水甲(jia)醇(chun),將此溶(rong)(rong)(rong)(rong)液(ye)置于(yu)冰浴中，緩緩通(tong)入二氧化硫(liu)氣體(ti)或加(jia)(jia)(jia)入液(ye)態二氧化硫(liu),至重量(liang)增加(jia)(jia)(jia)64克（1摩爾(er)）為止(zhi)。甲(jia)醇(chun)是配制此試(shi)劑(ji)的(de)(de)zui常用(yong)(yong)(yong)(yong)溶(rong)(rong)(rong)(rong)劑(ji)，因它(ta)對一般(ban)樣品和反應產物的(de)(de)溶(rong)(rong)(rong)(rong)解度均(jun)較(jiao)好(hao)；其他醇(chun)類如乙二醇(chun)等也可(ke)應用(yong)(yong)(yong)(yong)。配好(hao)的(de)(de)溶(rong)(rong)(rong)(rong)液(ye)不穩定，放置時會(hui)分解，開(kai)始(shi)分解較(jiao)快，過幾十(shi)小時后逐(zhu)漸(jian)變慢，即可(ke)應用(yong)(yong)(yong)(yong)。

進口標準品用(yong)(yong)時(shi)應同時(shi)以水(shui)(shui)標定(ding)，常用(yong)(yong)的(de)(de)標準(zhun)是水(shui)(shui)的(de)(de)甲(jia)醇溶液，也可(ke)用(yong)(yong)含(han)已知結(jie)晶水(shui)(shui)量(liang)的(de)(de)有機(ji)酸(suan)(suan)鹽(yan)類（如二水(shui)(shui)合酒石酸(suan)(suan)鈉）做為(wei)標準(zhun)。因系(xi)用(yong)(yong)于水(shui)(shui)的(de)(de)測(ce)定(ding)，所以所用(yong)(yong)的(de)(de)試劑、溶劑等均須預先經脫水(shui)(shui)處理(li)，容器也必須干燥，儲存(cun)與(yu)使用(yong)(yong)過程均應采(cai)取防(fang)潮(chao)措施，不使空(kong)氣中水(shui)(shui)分進(jin)入試劑，并應對所用(yong)(yong)溶劑進(jin)行(xing)空(kong)白(bai)滴(di)定(ding)，以求得其含(han)水(shui)(shui)量(liang)。含(han)水(shui)(shui)酒石酸(suan)(suan)鈉是一種(zhong)常用(yong)(yong)的(de)(de)含(han)水(shui)(shui)標準(zhun)物(wu)質,理(li)論(lun)含(han)水(shui)(shui)量(liang)為(wei)15.66%,在105℃加熱失重為(wei)15.65±15.65±0.02%,長期暴露于濕度為(wei)20～70%的(de)(de)空(kong)氣中,增重為(wei)0.01～0.09%。用(yong)(yong)含(han)飽和(he)水(shui)(shui)的(de)(de)甲(jia)苯和(he)純(chun)水(shui)(shui)的(de)(de)標定(ding)結(jie)果也是滿(man)意(yi)的(de)(de)。當然(ran),zui簡單還(huan)是用(yong)(yong)甲(jia)醇-水(shui)(shui)標準(zhun)溶液。

中(zhong)每摩爾碘(dian)所能滴定(ding)(ding)的(de)(de)水(shui)的(de)(de)量總是(shi)小于按上述反應(ying)式的(de)(de)計算(suan)值，因為配制的(de)(de)溶(rong)(rong)(rong)液(ye)不穩定(ding)(ding)，放(fang)置時(shi)不斷分(fen)(fen)(fen)解，一般在一個(ge)月即損失一半左右，其分(fen)(fen)(fen)解反應(ying)為： SO2+I2+2CH3OH─→2HI+CH3SO4CH3，因此(ci)試劑(ji)配制后放(fang)置時(shi)間較長即會失去效用(yong)(yong)。為克服此(ci)缺點，可將(jiang)此(ci)試劑(ji)分(fen)(fen)(fen)開配制成兩種(zhong)(zhong)溶(rong)(rong)(rong)液(ye)，分(fen)(fen)(fen)別存放(fang)，均較穩定(ding)(ding)。*種(zhong)(zhong)溶(rong)(rong)(rong)液(ye)中(zhong)含吡啶、二(er)(er)氧化硫和甲醇，第二(er)(er)種(zhong)(zhong)溶(rong)(rong)(rong)液(ye)為碘(dian)的(de)(de)甲醇溶(rong)(rong)(rong)液(ye)。使用(yong)(yong)時(shi),或(huo)事先將(jiang)二(er)(er)液(ye)混(hun)合(he),放(fang)置過夜后用(yong)(yong)作滴定(ding)(ding)劑(ji)；或(huo)將(jiang)樣(yang)品溶(rong)(rong)(rong)于*種(zhong)(zhong)溶(rong)(rong)(rong)液(ye)中(zhong)，以第二(er)(er)種(zhong)(zhong)溶(rong)(rong)(rong)液(ye)進行滴定(ding)(ding)。存放(fang)與使用(yong)(yong)時(shi)，仍(reng)須注意防止甲醇吸收空氣(qi)中(zhong)的(de)(de)水(shui)分(fen)(fen)(fen)及溶(rong)(rong)(rong)液(ye)中(zhong)碘(dian)的(de)(de)揮發(fa)。