Haitham Al-Madhagi, No. "Retention Times", in all forms of chromatography provide just ONE dimension of analysis, as part of an overall method. Alone, they are not used for quantitative identification of compounds (qualitative at best). "GC databases" are not relevant. "GC analysis" is not universal as the analysis variables are unlimited (It is a complex technique based on an analysis method, not a single test. The data obtained is only as good as the method used). GC analysis is not the same as using an analytical balance where you expect the same sample to show the same mass when you weigh it on different balances. Different instruments, columns, methods, settings, users etc all contribute to variations in results. You can not directly compare generalized retention time data to literature examples (with some exceptions for showing patterns and/or trends when identical instruments, columns, methods, settings etc are compared). The literature examples only serve as "examples", not databases. Some of these examples are also of very poor quality too.

Note: Appropriate algal analysis methods depend on which compound types are being investigated (and you did not provide any information about your samples). Depending on the specific compounds you wish to analyze, different sample preparation methods AND analysis techniques will be applicable. For example: GC-FID and GC-MS are sometimes used, after sample derivatization, to analyze lipid and/or fatty acids. Other types of compounds are not applicable to GC analysis at all (HPLC-DAD is another popular technique). The correct analytical techniques used must be correctly matched to the sample type(s) first, then appropriate methods developed for analysis. *These techniques take many years to learn at even the most basic level so be sure to discuss your project with your teacher or experienced professional before investigating to make the best use of your time.

First, which detector are you using? The method you mentioned is the Retention Time Matching, which is a common preliminar profiling method but it should be complemented with other confirmatory techniques for accurate identification.

It’s crucial to remember that while libraries can provide preliminary identification of compounds through GC-MS spectra, this identification should always be confirmed with analytical standards if they are available.

Regardless of the detector you are using, employing analytical standards for the compounds of interest is the most reliable approach to ensure accurate and definitive identification.

Gas chromatography compound identification using retention time alone is possible but not definitive. Comparing retention times with bibliographic sources or databases like NIST Chemistry WebBook, Kovats Retention Index Database, or Pubchem can provide tentative identifications. For reliable results, ensure consistent experimental conditions and consider using additional analytical techniques or known standards for confirmation.

Thank you very much @Abdelhak Maghchiche, @Jorge Antonio Custodio-Mendoza and @William Letter.