Deep eutectic solvent–based headspace single-drop microextraction for the quantification of terpenes in spices

Abstract

Deep eutectic solvents (DESs) were investigating as extracting solvent for headspace single drop microextraction (HS-SDME). The extraction efficiency of ten DESs mainly composed of tetrabutylammonium bromide (N 4444 Br) and long chain alcohols was evaluated for the extraction of terpenes from six spices (cinnamon, cumin, fennel, clove, thyme and nutmeg). The DES composed of N 4444 Br and dodecanol at a molar ratio of 1:2 showed the highest extraction efficiency and was selected to conduct the extractions of terpenes in the rest of the study. HS-SDME was optimized by design of experiments. Only two parameters from the four studied showed a significant influence on the efficiency of the method: the extraction time and the extraction temperature. The optimal extraction conditions were determined by response surface methodology. All extracts were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). More than 40 terpenes were extracted and identified in nutmeg, the richest extract in terpenes in this study. Quantitative analysis based on 29 standards was conducted for each extract. Good linearity was obtained for all standards (R 2 >0.99) in the interval of 1 to 500 µg/g. Limits of quantification ranged from 0.47 µg/g (borneol) to 86.40 µg/g (α-farnesene) with more than half of the values under 2 µg/g. HS-SDME is simple, rapid and cheap compared to conventional extraction methods. The use of DESs makes this extraction method "greener" and it was shown that DESs can be suitable solvents for the extraction of bioactive compounds from plants.

Deep Eutectic Solvents Application in Food Analysis

“…Currently, studies on the synthesis and application of HDESs for the extraction of a great variety of analytes from food matrices have expanded rapidly, which has led to an increase in the number of articles published in recent years. As can be seen in Table 2, several HDESs have been used for the extraction of both organic (phthalic acid esters [18,96,99], dyes [97,104,110,117], PAHs [17,85], sterols [98], pesticides [100,105,112,122,124,126,127], herbicides [102], insecticides [125], preservatives [101], pigments [86], antibiotics [87,103,108,114], fluorescent whitening agents [106], vitamins [107], mycotoxins [16], bisphenols [115], perfluoroalkyl substances [120] and terpenes [121]) and inorganic compounds (Co, Cd, Ni, As, V and Pb [109,111,113,116,118,119,123]) from aqueous phases (water [96,113,118,124], soft drinks…”

“…On the other hand, in order to improve the sensitivity towards volatile compounds, headspace microextraction techniques have been used, such as headspace SDME, which is faster and cheaper than other extraction methods, and allows extracting a wide range of components with diverse physicochemical properties in matrices where no pre-treatment is necessary. As an example, Triaux et al [121] used a HDES (tetrabutylammonium bromide (N 4444 Br):dodecanol, 1:2 molar ratio) as extracting solvent for the extraction of 67 terpenes from six spices (cumin, cinnamon, clove, fennel, nutmeg and thyme) used as bought without additional grinding. The DES was introduced into the needle of a GC microsyringe, which was inserted into the headspace of the vial where the sample was located.…”

“…Regarding the final determination of the analytes, different separation and detection techniques have been applied, being LC, both HPLC [17,18,86,87,[96][97][98][99]101,103,104,107,110,112,114,124,125] and UHPLC [115,120], the most extensively used, although some applications of micellar electrokinetic capillary chromatography [108] and GC [85,100,102,105,121,122,126,127] can also be found mainly for non-ionic HDESs, which are characterized by a higher volatility. These separation techniques have been coupled to different detection systems, including UV [18,87,96,97,99,103,107,110,112,124,125], DAD [86,104,114], variable wavelength detectors [98], FD [17,101], MS …”

Microextraction Techniques with Deep Eutectic Solvents

“…The application to 27 different terpens showed that half of the studied compounds had LOQs lower than 2 µg/g, as in the case of menthone, caryophyllene, borneol, which agrees with Tang's conclusions. Therefore, DES-HS-SDME is a simple, cheap, green, and efficient technique for the extraction of terpenes [96].…”

Phytomass Valorization by Deep Eutectic Solvents—Achievements, Perspectives, and Limitations

“…Advantages in extraction of metals from mixed oxide matrixes were described by the team headed by Abbott [34]. Triaux and his coworkers [35] found that the most important factors for separation efficiency were extraction time and temperature. Along with their application in chromatography and biomass processing, some illustrative results of extraction of value-added compounds from biomass are described too [8,[36][37][38].…”