Evaluation of injection techniques for triglycerides in capillary gas chromatography

✍ Scribed by K. Grob Jr.

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 488 KB
• Volume: 178
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(00)92496-8

✦ Synopsis

Precision and accuracy of vaporization, as well as cold on-column injections, were studied using triglycerides as a sample of very high boiling point. Cold oncolumn injection gave by far the most reproducible results (with standard deviations of 1 to 3%) normalized on internal standard. A weak discrimination of the larger triglycerides was assumed to be due to losses in the chromatographic column. Using a classical vaporizing injector, ca. 20% of the triglycerides were lost because of insufficient elution out of the syringe needle. Such losses explain virtually all the systematic errors occurring during splitless injections_ However, discrimination especially of the higher boiling tri_glycerides, as observed with split sampling, was consistently hisher, pointing to an additional, very inconsistent mechanism producing changes in the original composition of the part of the sample which enters the column. Standard deviations of data obtained with splitless injections were 9-l 3 %, and 1530% for split sampling.