In this study, five laboratories, namely, BRML (Romania), TUBITAK UME (Turkey), IMBIH (Bosnia and Herzegovina), BAM (Germany), and DTI (Denmark), developed and validated analytical procedures by ICP-MS, ICP-OES, MWP-AES, WD-XRF, and ID-MS for the determination of inorganic impurities in solid and liquid biofuels, established the budget of uncertainties, and developed the method for determining the amount of ash in the measurement range 0–1.2% with absolute repeatability less than 0.1% and absolute reproducibility of 0.2% (according to EN ISO 18122). In order to create homogeneous certified reference materials, improved methodologies for the measurement and characterization of solid and liquid biofuels were developed. Thus, information regarding the precision, accuracy, and bias of the method, and identifying the factors that intervened in the measurement of uncertainty were experimentally determined, supplementing the information from the existing standards in the field.

Most of the papers that treat the composition of essential oils for this purpose use GCMS or GCMS and GC-FID techniques for the identification and/or quantification of individual compounds. Therewithal, papers usually treat the composition as semi-quantitative (percentage composition as the area of ​​the peak of a particular compound in relation to the total area of ​​the peaks on the chromatogram, given as 100%). At the same time, the quality of the results is not treated in metrological terms. A GCMS method for the quantification of components present Helichrysum italicum hydro-distilled essential oil samples from Bosnia and Herzegovina with a similar composition was developed and optimized. The stability of the method set-up and adequacy of sample storage and manipulation was assessed. Calibration method and assessment of measurement uncertainty was established for neryl acetate, one of the major compounds with known health benefits.

The Lavandula genus is one of the world's most popular medicinal and aromatic plants and is rich in essential oil. Lavender (Lavandula angustifolia Mill.) and lavandin (Lavandula intermedia Emeric ex Loisel.) have high commercial values worldwide. However, their quality depends on genetic properties, environmental conditions, and cultural practices. Therefore, this research aimed to determine the antioxidant capacity and content of constituents in the essential oil of lavender and lavandin grown in the environmental conditions of central Bosnia and Herzegovina (B&H). Samples of lavender and lavandin (cv. grosso) were collected at Butmir, B&H. The tested properties were total phenolic, total flavonoids, antioxidant activity, essential oil content and content of constituents in essential oil. The quality of tested plants was statistically significantly dependent on the cultivar. The highest values of total phenolic, flavonoids, and antioxidant capacity were recorded in the lavender (54.26 mg GAE g -1 , 41.49 mg CAE g -1 and 17.49 µM Fe 2+ g -1 , respectively), while the lowest was in the lavandin (39.30 mg GAE g -1 , 24.07 mg CAE g -1 and 10.84 µM Fe 2+ g -1 , respectively). Essential oil content ranged from 4.44 (Lavender) to 8.25 mL 100 g -1 (lavandin). Essential oil of lavender and lavandin were rich in linalool.