Determination of the precision and application of the new HSS-GC-FID method for determination of volatile components in olive oil

Maslinovo se ulje koristi u ljudskoj prehrani još od davnih vremena, a posebice području Mediterana gdje se nalaze brojni maslinici. Sve veća pažnja maslinovom ulju posvećena je nakon objave rezultata istraživanja koja su pokazala da određene sastavnice maslinova ulja ispoljavaju pozitivne učinke na zdravlje. Kvaliteta maslinovog ulja usko je povezana s prisutnošću kratkolančanih alkohola u maslinovom ulju. Male količine etanola i metanola u ulju dozvoljene su s obzirom da se spomenuti alkoholi stvaraju u plodu tijekom njegova sazrijevanja. S druge strane, visoke koncentracije etanola u ulju nastaju procesom fermentacije ponajviše za vrijeme skladištenja plodova. Europska komisija donijela je 1991. godine Uredbu br. 2568/91 u kojoj je definirana podjela u 9 kategorija s obzirom na određene karakteristike ulja. U ovom radu opisano je ispitivanje preciznosti, na razini ponovljivosti i srednje preciznosti, nove HSS-GC-FID tehnike za određivanje sadržaja alifatskih alkohola u maslinovom ulju te primjena navedene tehnike za analizu vlastitog maslinovog ulja. RSD vrijednosti za ponovljivost bile su manje od 0,2 %, a za srednju preciznost od 1,1 %. Na temelju dobivenih rezultata zaključeno je da je navedena metoda precizna. Također, uočeno je i da se preciznost metode povećava korekcijom vremena zadržavanja analita s vremenom zadržavanja unutarnjeg standarda. Naposljetku, navedena metoda primijenjena je za analizu vlastitog maslinovog ulja. S obzirom na vrlo niske pronađene koncentracije etanola, metanola i etilacetata, zaključeno je da se analizirano ulje, prema udjelu niskolančanih alkohola, može okarakterizirati kao visokokvalitetno maslinovo ulje.The use of olive oil in human diet has been known since ancient times, especially in the Mediterranean area where many olive trees are planted. Olive oil has become the center of attention after publishing some research results which have shown that certain components of olive oil have beneficial effects on human health. Quality of the olive oil is closely linked with the presence of short chained alcohols in the oil itself. Small amounts of ethanol and methanol in the oil are allowed since they are formed during the maturation of olives. On the other hand, high concentrations of ethanol in the oil appear during the fermentation processes occurring mainly throughout olive fruit storage. European commission issued in 1991 Act no. 2568/91 which defines classification of the oils in 9 categories regarding certain characteristics of the oil. Examination of the precision, as repeatability and intermediate precision, of the new HSS-GC-FID technique for the determination of the aliphatic alcohols content in the olive oil, as well as the application of the mentioned technique on the analysis of my own olive oil is described in this paper. RSD values were lower than 0.2 % for repeatability and lower then 1.1 % for intermediate precission. Based on the results obtained it is concluded that the used method is precise. Moreover, it is noticed that the precision of the method is increased after correction of the retention time of the analite with the retention time of the internal standard. In the end, the method was applied on the analysis of my own olive oil. Regarding the low concentrations of ethanol, methanol and ethyl acetate found in the oil, it is concluded that, based on the short chained alchohols content, the analyzed oil can be characterized as high-quality oil