Case Study 1 Reducing Baseline Shift and Noise for Gradient Analysis

1 Case Study 1 Reducing Baseline Shift and Noise for Gradient Analysis 

2 Case Study 2 Poor Peak Area Precision Encountered During HPLC System Calibration 

Two real-world examples are used to illustrate how to resolve this common problem encountered during the calibration of an autosampler (Chapter 9). In Table 10.1, the precision of peak area was found to be 1 % RSD, which was above the acceptance criterion of 0.5% RSD. Repeating the experiment showed similar precision results. Since a worn sampling syringe of the autosampler is the most common cause for poor precision, it was replaced. The peak area precision was found to be -0.3% RSD after this replacement. 

Run Peak Area Peak Area After replacing syringe 

In the second scenario shown by the data in Table 10.2, poor precision was encountered in both the retention time and peak area of an analyte. Scrutiny of the data showed that both retention time and peak area tended to trend upward. Troubleshooting the autosampler by replacing the sampling syringe yielded no improvements. The poor precision of retention time hinted to possible column problems. The column was therefore replaced and acceptable precision was restored. 

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