Discovered triethylamine as impurity in synthetic DNAs for and by electrochemiluminescence techniques

The purity of the synthetic oligonucleotides is very important because it is crucial for the accuracy of the established biological assays. Herein, it was discovered that one impurity in synthetic DNAs might affect the experiment results of electrochemiluminescence (ECL) detection techniques, which was never reported before. According to a series of experiments using ECL detection methods combined with capillary electrophoresis (CE) (CE–ECL), the impurity was identified as triethylamine (TEA), which came from incomplete removal after HPLC purification of synthetic DNAs. Moreover, CE–ECL technique was for the first time to be proposed for discovering, identifying and sensitive determining the possible impurity such as TEA in various DNA samples, which was usually neglected by other detection techniques for purification quality control of synthetic oligonucleotides. A detection range from 5.00×10−10 to 2.00×10−5 M with a detection limit as low as 50 nM (S/N=3) was reached for TEA. Through further designed ECL methods and data analysis, situations which would be really affected by the impurity of TEA were studied. To avoid or eliminate the impact of the TEA impurity on ECL applications, judgment basis for choosing purification ways was discussed according to individual requirements.