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synopsisTwo types of high performance size exclusion chromatographic (SEC) columns were tested for the characterization of starch samples: pbndagel and Aquapore. The mobile phase was dimethyl sulfoxide (DMSO) containing 0.03 M sodium nitrate maintained at 80°C. The results indicated that both pBondagel and Aquapore can be used to determine the relative molecular weight of starch. The exclusion limits for these columns exceed ten million. Preliminary results using pstyragel are also reported. Examples of SEC analysis of starch, including starch with anionic groups, are given.

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The use of wave-length modulation as a tool for minimizing spectrometer spectral misalignment is examined. A vibrating quartz plate is employed to repetitively scan a small wave-length interval at the exit slit of a spectrometer. Increased latitude is thereby provided for any slit or wave-length misalignment of the spectrometer, as long as the correct signal detection system is employed. Investigation of the effects of wave-length modulation on a typical line spectrum has revealed signal averaging as the optimum detection system for this approach. From this, additional approaches are suggested for manual and automatic routine correction of spectrometer wave-length drift using existing optical systems. Also, a new technique is suggested for automatic feedback correction of the spectrometer using an on-line digital computer. Methods of implementation of all these procedures are considered and discussed.