Resolution troubleshooting

There were a few incidents of pressure relief valve actuation, especially during troubleshooting of the instability problem. The committee believes that resolution of the instability problem will alleviate this problem. 

There are numerous papers that refer to the quantification of tocopherols and tocotrienols using HPLC methods. Normal-phase HPLC methods with a silica column as well as reversed-phase HPLC methods with a C18 column are commonly used. A silica normal-phase column is able to separate all eight tocopherols and tocotrienols in a typical chromatographic procedure. Because plant tissues possess most forms of tocopherol and tocotrienol, it is recommended that the normal-phase HPLC method be applied to food samples from plants. In the reversed-phase HPLC method, [3- and y-tocopherol and (3-and y-tocotrienol are not usually completely separated. This method can be used in animal tissues, which either lack or have reduced levels of [3- and y-tocopherol and (3- and y-tocotrienol. The resolution of the normal-phase HPLC method is higher than that of reversed-phase HPLC method however, the reversed-phase HPLC column is more long-lasting than the normal-phase HPLC column (see Critical Parameters and Troubleshooting). 

The pressure to find a successful resolution to a processing problem can be intense. Once a processing glitch has been determined to be suitably serious to warrant investigation, one must compare the conditions of the wayward batches with those of successftd batches. The troubleshooting approach outlined in Table 15.2 can be used to solve problems quickly. 

Several case studies concerning baseline and data performance problems, as well as troubleshooting examples, are selected here to illustrate problem diagnosis and resolution. 

For general advice on improving poor resolution, see Chapter 12 on Troubleshooting. 

Such little information as is available on troubleshooting in high-resolution gamma spectrometry systems is scattered through the manuals of equipment suppliers 1 would particularly commend those of Canberra, PGT and ORTEC. 

As an example of real troubleshooting action, a specific amplifier, Canberra 2020, which is very frequently used In high resolution spectroscopy systems, will be considered. 

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