# Solution 6.1 - Chemometrics: Data Analysis for the Laboratory and Chemical Plant

## Education Article

**Published:**Jan 1, 2000**Channels:**Chemometrics & Informatics

1. The graph using all points is given below.

Removing the first two points gives the following graph.

The first two points are clearly noise so the correlation coefficient drops. Removing these gives a graph that is easy to interpret. The dip in the middle is a composition 2 point, but there are two plateaux which indicate composition 1 regions. Notice that the plateau for the slower eluting compound is not so pronounced as for the first one, suggesting it may be an embedded peak.

The graphs could be improved by taking logarithms.

2. The graph from the derivative calculation is as follows.

Using a log scale gives the following graph.

There are clearly two points of maximum purity, but this is much sharper for the fastest eluting component, suggesting that only this component has a selective or composition 1 point. The purest points are at times 10 and 22.

3. The graph is given below. It is clear that point 10 is a pure point. It is not entirely clear about point number 22, but this pattern is indicative of a small embedded peak.