一、背景

為了保證(zheng)鍍(du)(du)層質(zhi)量(liang)(liang)，在(zai)(zai)電(dian)(dian)鍍(du)(du)溶(rong)液(ye)(ye)(ye)中(zhong)(zhong)加(jia)(jia)入某些(xie)有機物作為添加(jia)(jia)劑(ji)，其中(zhong)(zhong)聚乙(yi)二醇(chun)(PEG)是一(yi)種重要的穩定(ding)劑(ji)。在(zai)(zai)實際電(dian)(dian)鍍(du)(du)過程(cheng)中(zhong)(zhong)，須不斷補(bu)加(jia)(jia)PEG以(yi)保持其值的穩定(ding)，所以(yi)，準確測(ce)定(ding)電(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)中(zhong)(zhong)PEG的含量(liang)(liang)有一(yi)定(ding)意義。對(dui)于純(chun)PEG水溶(rong)液(ye)(ye)(ye)，其含量(liang)(liang)測(ce)定(ding)方法已(yi)有報道，該論(lun)文發表了以(yi)來，許(xu)多(duo)同(tong)業人員詢問相關內容，有企(qi)業委托我們對(dui)電(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)中(zhong)(zhong)PEG含量(liang)(liang)測(ce)定(ding)方法進行研究。本文在(zai)(zai)前期研究的基(ji)礎上，通過消除錫電(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)中(zhong)(zhong)一(yi)些(xie)共(gong)存物質(zhi)的干擾，確定(ding)了電(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)中(zhong)(zhong)PEG含量(liang)(liang)的測(ce)量(liang)(liang)方法。

二、實驗試劑和儀器

主要實驗(yan)試劑有(you)：碘(dian)，I2，純(chun)(chun)度(du)≥99.8%；碘(dian)化(hua)鉀(jia)KI；純(chun)(chun)度(du)t≥98.5%；氯化(hua)鋇、高錳酸鉀(jia)、草(cao)酸、EDTA、過硫酸銨(an)、雙(shuang)氧水等(deng)均為(wei)分析純(chun)(chun)。聚乙二醇(chun)6000（化(hua)學純(chun)(chun)）。實驗(yan)采用紫外可見光(guang)(guang)分光(guang)(guang)光(guang)(guang)度(du)計（日本島津UV-2450)分析溶液的吸光(guang)(guang)度(du)。

三、測定方法(fa)與結果(guo)

3．1標準(zhun)PEG溶(rong)液(ye)配(pei)制和測定

在50mL容量(liang)(liang)瓶中，加入(ru)50mg·L-1PEG6000標(biao)準溶(rong)(rong)(rong)(rong)液(ye)3mL，然后加入(ru)一(yi)定量(liang)(liang)的(de)BaCl2和I2標(biao)準溶(rong)(rong)(rong)(rong)液(ye)后定容至刻(ke)度線。該溶(rong)(rong)(rong)(rong)液(ye)用(yong)于(yu)(yu)測(ce)定標(biao)準PEG溶(rong)(rong)(rong)(rong)液(ye)的(de)吸(xi)光(guang)(guang)(guang)度，讀(du)取記為(wei)A0同時配制空白(bai)溶(rong)(rong)(rong)(rong)液(ye)用(yong)于(yu)(yu)紫(zi)外分(fen)光(guang)(guang)(guang)光(guang)(guang)(guang)度計調零。

3．2樣品測定

選取(qu)待測樣品(pin)，估計待測樣品(pin)中PEG6000的(de)濃度。通(tong)過稀(xi)釋(shi)的(de)方(fang)法使其含量接(jie)近50mg/L，記(ji)下稀(xi)釋(shi)倍數,記(ji)為M。

在50mL容量(liang)瓶中，加(jia)(jia)入待測(ce)樣(yang)品溶(rong)(rong)(rong)液(ye)3mL加(jia)(jia)入少量(liang)水稀(xi)釋，用滴(di)(di)定(ding)(ding)管逐滴(di)(di)加(jia)(jia)入高錳酸(suan)鉀標準(zhun)(zhun)(zhun)溶(rong)(rong)(rong)液(ye)，邊(bian)滴(di)(di)邊(bian)搖(yao)，至溶(rong)(rong)(rong)液(ye)呈微紅色停(ting)止滴(di)(di)定(ding)(ding)；然后用滴(di)(di)定(ding)(ding)管逐滴(di)(di)加(jia)(jia)入草酸(suan)標準(zhun)(zhun)(zhun)溶(rong)(rong)(rong)液(ye)，邊(bian)滴(di)(di)邊(bian)搖(yao)，至溶(rong)(rong)(rong)液(ye)微紅色褪去停(ting)止滴(di)(di)定(ding)(ding)。接(jie)著(zhu)，加(jia)(jia)入一定(ding)(ding)量(liang)的BaCl2和I2標準(zhun)(zhun)(zhun)溶(rong)(rong)(rong)液(ye)后定(ding)(ding)容至刻度(du)線。該溶(rong)(rong)(rong)液(ye)用于測(ce)定(ding)(ding)待測(ce)試樣(yang)的吸光度(du)。同(tong)時制作三(san)個式樣(yang)，讀數分別(bie)記為A1、A2、A3。

3．3計算方法

A=(A1+A2+A3)／3(1)

式(shi)中：c，測定樣品濃度，mg·L-1。

四、結論

電鍍液(ye)(ye)中甲基磺酸亞錫的存(cun)在于擾對聚乙二(er)醇含(han)量的測(ce)定(ding)(ding)，實(shi)驗采用(yong)高(gao)錳酸鉀為氧化(hua)劑消除Sn2+的干擾后，利用(yong)紫外分光光度計(ji)測(ce)定(ding)(ding)出電鍍液(ye)(ye)中PEG含(han)量。經企業實(shi)際應用(yong)效果良(liang)好，表明該(gai)方法測(ce)定(ding)(ding)電鍍液(ye)(ye)中PEG含(han)量準確(que)性高(gao)、穩定(ding)(ding)性好、操(cao)作簡單。