电导率法筛选镉离子印迹聚合物功能单体

Screening of functional monomers of cadmium ion imprinted polymer by conductivity method

通过使用电导率仪测试了模板(氯化镉)和功能单体结合前后的电导率变化量(Δσ),筛选了适用于制备镉离子印迹聚合物的功能单体(氨基酸,核苷酸和核苷等)。结果显示:氨基酸中,以含有一个巯基的半胱氨酸与镉离子的结合前后的Δσ最高,为104.4;同样含有一个巯基的谷胱甘肽与镉结合前后的Δσ与半胱氨酸相当;分子结构中含有两个巯基的二硫苏糖醇和镉离子的结合前后的Δσ又高于半胱氨酸和谷胱甘肽;巯基是能够与镉离子发生结合的重要官能团;八种核苷一磷酸与镉结合前后的Δσ大致排序为:GMP、dGMP>AMP、UMP>TMP、dAMP、CMP、dCMP;几种核苷与镉结合前后的Δσ很小,可见核苷酸中的磷酸基团是与镉离子结合的重要基团。研究中,还优化了用于电导法筛选功能单体的HEPES缓冲液的最优pH为7.5。该研究所采用的方法可以快速准确地筛选出能够与镉发生结合的功能单体,为后续的镉离子印迹物的制备提供了重要的试验基础。

The change of conductivity(δσ)before and after the combination of template(cadmium chloride)and functional monomer was measured by conductivity meter.The functional monomers(amino acids,nucleotides,nucleosides,etc.)suitable for the preparation of cadmium ion imprinted polymer were screened.The results showed that the highestΔσof amino acids was 104.4 before and after the combination of cysteine with one sulfhydryl group and cadmium ion.TheΔσof glutathione,which also contained a sulfhydryl group,was equivalent to cysteine before and after binding with cadmium.TheΔσof dithiothreitol with two sulfhydryl groups in the molecular structure was higher than that of cysteine and glutathione before and after the combination with cadmium ion.Sulfhydryl group was an important functional group which could combine with cadmium ion.The order ofΔσbefore and after the binding of eight nucleosides monophosphate with cadmium was:GMP,dGMP>AMP,UMP>TMP,dAMP,CMP,dCMP.TheΔσof several nucleosides before and after binding with cadmium was very small.It could be seen that the phosphate group in nucleotides was an important group for binding with cadmium ions.In this study,the optimal pH value of HEPES buffer was 7.5.As a result,this method could quickly and accurately screen functional monomers that could combine with cadmium,which provided an important experimental basis for the subsequent preparation of cadmium ion imprinted compounds.