HPLC Defect and Instrument Qualification

A client had problems with a new HPLC instrument. The method that was under development did not give reproducible results. A dominant signal which existed almost everywhere in both samples and standards was one of the concerns. Among the other matters were deviations of the retention times, sample preparation, accuracy, and precision of the measurements.            

Professionals still underestimate the need for qualification of the instruments from category B, such as balances and pH meters. However, they are a source of errors that multiply depending on maintenance, user training, and other factors. The establishment of procedures with appropriate control samples provides an error-free environment of operation. 

Following a need analysis, we have determined that accuracy, precision, and bias are the result of improper qualification of the HPLC instrument along with other devices such as pH meter and balances. The progressive accumulation of impurities in the apparatus and the column was also not taken into consideration as a cause of serious problems. Most notable was that the dominant signal that existed in the majority of the samples was a result of contaminations pulled out from the needle of the autosampler. And this fact derived from the manufacturer’s defect. 

As the instrument was new, we connected with the manufacturers of the HPLC and explained the problem with the dominant signal and our evaluation. After a series of phone conferences, conversations and tests, they sent us several different types

of needles for testing. Some of them showed excellent results, and we selected them for further use. The other abnormalities were the result of insufficient training of the HPLC operator and a lack of appropriate procedures for instrument qualification. We provided the customer with the necessary educational materials and training. The newly established method was validated and put in use.

Both our customer and HPLC manufacturer were satisfied with the cooperation. The customer was able to get reliable results from the newly developed methods. In parallel, we helped the HPLC manufacturer to identify a substantial defect in an expensive new device, which prevented significant losses for the HPLC company.