Quantification of 3,3-dimethyl-1-butanol (DMB) in olive oil: a rapid and novel method

Abstract

A novel Headspace Gas Chromatography-Mass Spectrometry (HS-GC/MS) method for identifying and quantifying 3,3-dimethyl-1-butanol (DMB), a bioactive compound, in extra virgin olive oil was developed. In this study, solvents with similar properties to DΜB but potentially different molecular masses, namely isopropanol, n-butanol, n-pentanol, and 2-penthanol, were tested and 2-pentanol was selected as the internal standard due to both chromatographic separation and distinctive mass spectrum pattern. The method for DMB determination and quantification was validated according to Eurochem CITAC Guide. Sensitivity, specificity, linearity, accuracy, and precision parameters were evaluated. The validation process also included assessment of the method’s robustness and repeatability, ensuring that it produces reliable results for future analyses of olive oil. A linear regression equation was developed for 100–5,000 µg/L levels as y = x.11.462.10−6, where y is the peak area ratio, and x is the DMB concentration in µg/L with 0.9989 correlation coefficient (R2), and uncertainty budget was estimated as 8.22% at k = 2 confidence level. At the same time, the lower range of 0–100 µg/L was described with equation y = x.17.860.10−6 and 0.9983 correlation coefficient (R2). The uncertainty of the DMB measurements in extra virgin olive oil was estimated as 7.0% at a k = 2 confidence level. This new method was applied to determine the presence of DMB in various olive oil samples from Greece and Türkiye. The DMB values for olive oil samples were: N1(Plus health blue multi varietal ) 9.7 μg/L, Ν2 (Plus health DMB multi varietal)11.4 μg/L, N3 (Fyllikon first harvest organic) 8.3 μg/L, N4 (Plus health green multi varietal) 7.8 μg/L, N5 (Agourelaio early harvest organic) 6.8 μg/L, N6 (unknown) 4.8 μg/L, N7 (Armonia monovarietal organic) 4.8 μg/L and N8 (Edremit type olive oil from Kırkağaç, Manisa) 8.8 μg/L and N9 (Market product in Türkiye) 1.5 μg/L.