23–26 Sept 2026
Metropol Lake Resort
Europe/Zurich timezone

Internal Standards Use In Analyses of Cannabinoids

24 Sept 2026, 18:10
5m
Biljana Hall (Metropol Lake Resort)

Biljana Hall

Metropol Lake Resort

E-poster Analytical and environmental chemistry Parrallel E-poster Presentations (1B)

Speaker

Dr Marjan Piponski (Quality Control Department in Pharmaceutical Company Replek Pharm)

Description

The dominant analytical techniques are of HPLC group of methods, predominantly with UV-PDA detecting for routne QC analyses in labs. Almost all of them are based on External Method of calculation of results. In this way, all standards and prepared samples are injected in replicates, which eliminate or minimize the errors of equipment malfunction or complexity and skills of analyst for sample preparation. Using of adequate Internal Standards substance may reduce these expenses by improvement of cost-efficiency of analysis by reducing number of injections, without jeopardizing the accuracy of results. We tested many substances and found 2 interesting of them, one more polar eluting as first significant peak on chromatogram, 4-methoxystilbene, and second is pentachlorobenzene, which in RP-C18 elution with acidified acetonitrile elutes near after the CBD molecule. The Response Factors Area/Conc were calculated for both Internal Standards and 5 main cannnabinoids, CBDA, CBD,CBN,THC and THCA, for plotting calculation linearity curve. If second IS2-pentachlorobenzene is used, monitoring is at UV=220nm, whie if we use IS1-4-methoxystylbene, Response Factor RF at 309-310nm gives slightly different results, whicg can be neglected if we use high peaks of Internal Standards. These supplication of of Internal Standards might simplified and create cheaper and Green-er methods.
Keywords: Cannabinoids, Quantification, HPLC, UV, PDA, Method, Internal Standard

References: , 1 PhEur 2026, 2 USP 2026, 3HPLC for Practicing Scientist(II);M.Dong.

Author

Dr Marjan Piponski (Quality Control Department in Pharmaceutical Company Replek Pharm)

Co-author

Dr Antonija Beneta (Managing Director and Research Leader)

Presentation materials

There are no materials yet.