Errors in the Area Determination of Incompletely Resolved Chromatographic Peaks

Three graphs that indicate the relative error in peak area when two incompletely resolved peaks are integrated by the vertical drop method are presented. The following cases are investigated: two Gaussian peaks, two exponentially modified peaks, and an exponentially modified peak followed by a Gaussian peak; in each case, the peaks are of equal width. Area ratios range from 1:1 to 10:1, tailing factors of asymmetric peaks range from 1.10 to 2.0, and the resolution of the peak pair varies between 1.5 and 0.75. Depending on the size ratio, tailing, and resolution, the errors in peak area can be large, for example, up to plus or minus 40% of the true area within the range of peak pairs investigated. In all cases, the small peak is more impaired than the large one, with impairment depending on the size ratio.