DIRECT ELECTROCHEMICAL DETECTION OF PURINE-BASED AND PYRIMIDINE-BASEDNUCLEOTIDES WITH SINUSOIDAL VOLTAMMETRY

Sinusoidal voltammetry was employed to detect both purine-and pyrimidi ne-based nucleic acids, Adenine and cytosine, representing these two c lasses of nucleic acids, could be measured with submicromolar detectio n limits at a copper electrode under these conditions, where the sensi tivity for adenine was much higher than that for cytosine. Detection l imits for purine-containing nucleotides [e.g., adenosine 5'-monophosph ate (AMP), adenosine 5'-diphosphate (ADP), and adenosine 5'-triphospha te (ATP)I were on the order of 70-200 nM using this method. These dete ction limits are achieved for native nucleotides and are over 2 orders of magnitude lower than those found with UV absorbance detection. Sub micromolar detection limits were also obtained for pyrimidine-based nu cleotides, which could also be detected with high sensitivity due to t he presence of a sugar backbone that is electroactive at the copper su rface. This detector is not fouled by the nucleotides and may be used for the sensitive detection of analytes eluting continuously in a flow ing stream, i.e., from a chromatography column or an electrophoresis c apillary.