For optimum S/N enhancement, spectral data should be smoothed with a smooth width that is no more than twice the width of a spectral peak taken at half its maximum intensity. Estimate from the data of Figure 5-15 (a) the maximum smooth width for the peak on the left side of the spectrum and (b) for the peak on the right.

FIGURE 5-15 Effect of smoothing on a noisy absorption spectrum of tartrazine: (A) raw spectrum, (B) quadratic 5-point smooth of the data in A,(C) fourth-degree 13-point smooth of the same data, (D) tenth-degree 77-point smooth of the data