Patent ID: 8150635
Filing Date: 2012-04-03
Classification: G01N

Abstract:
1. A method for determining a nucleotide sequence comprising: injecting a solution containing a sample DNA into a chip cartridge provided with a detecting electrode, to which a probe DNA is immobilized; introducing an intercalator solution containing an intercalator into the chip cartridge; obtaining a current-voltage characteristic curve by measuring current values in the solution due to an electrochemical reaction of the intercalator through the detecting electrode by applying voltages to the detecting electrode; obtaining a differential curve of the current-voltage characteristic curve, with respect to voltage; defining a peak voltage value as a voltage value at which the differential curve zero-crosses in a voltage range between predetermined lower and upper limit values; defining a peak current point as a point on the current-voltage characteristic curve at the peak voltage value; defining a peak current value obtained from the current-voltage characteristic curve at the peak current point; determining a linear expression approximating the current-voltage characteristic curve between the peak current point and an inflection point, wherein the inflection point is at a value of voltage less than the peak voltage value; obtaining an intersection-point voltage value at an intersection-point of the current-voltage characteristic curve and the linear expression, in a voltage range which is less than the voltage of the inflection point; defining an offset voltage by subtracting a predetermined offset value from the intersection-point voltage value; obtaining a baseline by linearly approximating the current-voltage characteristic curve between the offset voltage and the intersection-point voltage value; obtaining a baseline current value, by assigning the peak voltage value for the baseline; obtaining a net current value by subtracting from the peak current value, the baseline current value; and identifying a nucleotide sequence in the sample DNA, using the net current value.