Trace determination of DNA in an amaryllidaceae plant, Narcissus tazetta by square-wave stripping voltammetry based on guanine signal

This study is, to our knowledge, the first application of electrochemical DNA biosensor for the quantification of DNA in plant extracts. The DNA biosensor was assembled by immobilizing the double-stranded fish sperm DNA on the surface of a singleuse pencil graphite electrode. Square-wave voltammetric method with the baseline correction was carried out to evaluate the oxidation signal of the guanine base. The experimental variables such as solution pH, buffer concentration, immobilization time, stirring speed, and square-wave parameters were optimized. The extremely low detection limit (0.36 ng/mL) was coupled to a good surface-to-surface reproducibility (a relative standard deviation of 8.4% for 7 repetitive measurements of 40 ng/mL). The renewable and low-cost DNA biosensor developed in this study using pencil graphite electrode was applied to the determination of DNA isolated from an Amaryllidaceae plant, Narcissus tazetta.