Zero-line

The zeroline is a straight line constructed from the offset of the two isotherms at the beginning and end of heating or cooling. The start and end times correspond to the start and end times of the heating or cooling cycles. The Y-value is taken from the heat flow value at the end of the respective isotherms. The zeroline is constructed over time and subtracted from the heat flow signal of the measurement. With well calibrated DSC and small temperature measuring ranges, the zero line corresponds approximately to the heat flow signal of the empty furnace. However, the linear behaviour is usually no longer given at large temperature ranges, which is why non-linear curves should be corrected by measurements with empty crucibles (blank measurements). After this correction, the zero line should be redetermined and subtracted from the measurement.