To the best of our knowledge, so far, no study has been conducted about the comparison of the total fatty acid concentration in the four bee products (honey, bee pollen, bee bread, and propolis) collected from Lithuania. Therefore, we aimed to optimize the derivatization parameters and to investigate a simple and sensitive gas chromatography-flame ionization detection (GC-FID) method to determine fatty acids. The optimal derivatization parameters were used to analyze fatty acids in the bee products. Regarding sample preparation, three derivatization parameters were compared (temperature and extraction time with BF3/MeOH reagent) in order to obtain a high amount of the total fatty acids of interest from the fatty acid methyl ester (FAME) standard. The results showed that the highest total yield of fatty acids was conducted by using the conventional heating process at 70 °C for 90 min. Under optimal conditions, there was obtained excellent linearity for fatty acids with determination coefficients of r2 > 0.9998. The LODs and LOQs ranged from 0.21 to 0.54 µg/mL and 0.63 to 1.63 µg/mL, respectively. This method has been successfully applied to the qualitative analysis of fatty acids in bee products. The above findings might provide a scientific basis for evaluating the nutritional values of bee products.

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.

The beneficial health properties of organic acids make them target compounds in multiple studies. This is the reason why developing a simple and sensitive determination and investigation method of organic acids is a priority. In this study, an effective method has been established for the determination of organic (lactic, glycolic, and malic) acids in saffron stigmas. N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) was used as a derivatization reagent in gas chromatography combined with mass spectrometric detection (GC/MS). The saffron stigmas extract was evaporated to dryness with a stream of nitrogen gas. The derivatization procedure: 0.1 g of dried extract was diluted into 0.1 mL of tetrahydrofuran, then 0.1 mL MTBSTFA was orderly and successively added into a vial. Two different techniques were used to obtain the highest amount of organic acid derivatives from saffron stigmas. To the best of our knowledge, this is the first report of the quantitative and qualitative GC/MS detection of organic acids in saffron stigmas using MTBSTFA reagent, also comparing different derivatization conditions, such as time, temperature and the effect of reagent amount on derivatization process. The identification of these derivatives was performed via GC-electron impact ionization mass spectrometry in positive-ion detection mode. Under optimal conditions, excellent linearity for all organic acids was obtained with determination coefficients of R2 > 0.9955. The detection limits (LODs) and quantitation limits (LOQs) ranged from 0.317 to 0.410 µg/mL and 0.085 to 1.53 µg/mL, respectively. The results showed that the highest yield of organic acids was conducted by using 0.1 mL of MTBSTFA and derivatization method with a conventional heating process at 130 °C for 90 min. This method has been successfully applied to the quantitative analysis of organic acids in saffron stigmas.

Oral bioavailability of flavonoids, including G. biloba extract, is limited due to their chemical complexity, which determines slow dissolution in vitro behavior of the extract. The overall research objective was to compare the effect of increasing freeze-dried G. biloba extract (GFD) concentrations in carboxymethyl cellulose (CMC) films on their mechanical properties, release profile of flavonoid glycosides, stability and disintegration time. Physicochemical evaluation of films was performed by SEM and FTIR. The mechanical properties and in vitro release profile of flavonoid glycosides from the prepared films were characterized in the study. The higher elongation at break and tensile strength values, quick release of flavonoids and good stability were observed in formulation, coded FRG—15 (the film contained 0.4 g of GFD, 0.3 g of glycerol and 2 g of 2% CMC), (p < 0.05). Dissolution rate tests showed that approximately 85% of loaded flavonoid glycosides had been released; the release profile of flavonoid glycosides from FRG-15 had levelled off after only 15 min. The results could lay the groundwork for further studies, concerning the development of sublingual films as G. biloba extract-based dosage forms, which might increase the multifunctional properties and pharmacological activity closer to the desired level.

У цьому дослідженні основна увага була приділена отримання зразків бурштинової кислоти з біологічної сировини і умов оптимізації отримання похідних з використанням методу ГХ-МС. Бурштинова кислота, попередник широкого діапазону біологічних сполук, особливо важлива для накопичення метаболіту мітохондрій сукцината (цикл лимонної кислоти), а під час ішемії контролює реперфузійне пошкодження за допомогою продукування мітохондріального реактивного кисню. Точне визначення речовини для аналізу є ключовим в метаболоміці для використання в якості низькомолекулярних біомаркерів в разі поліпшення діагностичних методів. Методи. Метод газової хромато-мас-спектрометрії (ГХ-МС). Для кількісного визначення використаного процесу дериватизації бурштинової кислоти шляхом силілювання з використанням-біс-(триметилсиліл)-трифторацетаміда (BSTFA). Результати. Дериватизатор BSTFA, час дериватизації 3-4 години і температура дериватизації 70 °C були обрані в якості оптимальних умов процесу для кількісного визначення бурштинової кислоти методом ГХ-МС в біологічних зразках. Результати показують, що метод ГХ-МС СДІ з випаровуванням найбільш ефективний для кількісного визначення сукцината в біологічних зразках після ішемії / реперфузійного ушкодження. Селективне детектування іонів (СДІ) дозволило контролювати підмножина фрагментів зі зв'язаними значеннями маси в певному діапазоні часу утримування (RT) для набору цілей. Висновки. ГХ-МС має кілька переваг для вимірювання концентрації сукцинату в невеликих зразках тканин нирки (ліофілізовані мітохондрії). Метод може бути застосований в невеликих шматочках тканини-зразки біопії, тканини з різних органів Ключові слова: бурштинова кислота, газова хромато-мас-спектрометрія, дериватизація, BSTFA, метаболоміка, ГХ-МС Дата надходження рукопису 12.06.2018