222
Deep Eutectic Solvent-Based Vortex Extraction Combined
with Emulsification Liquid-Liquid Microextraction
Aydin et al. (2018) developed a new technique using deep eutectic solvent (choline
chloride/phenol 1:4 molar ratio) as a water-miscible extraction solvent for the
extraction of curcumin (Fig. 6.14). Recoveries of curcumin using different deep
eutectic solvent were above 96% (Aydin et al. 2018).
Dispersive Solid-Phase Extraction in Combination with Deep Eutectic
Solvent-Based Air-Assisted Liquid-Liquid Microextraction
The proposed method is represented in Fig. 6.15. The process started with dispersive solid-phase extraction method. Then air-assisted liquid-liquid microextraction
method was applied. In the proposed method, the synthesized deep eutectic solvent
was used as an elution/extraction solvent. Results showed many advantages such as
good repeatability, high enrichment factors and extraction recoveries, low limits of
detection and limits of quantification, and simplicity of operation. According to
Mohebbi et al. (2018), this method can be used for the routine analysis of many
drugs in the pharmaceutical and clinical laboratories with no harm on human health
and environment (Mohebbi et al. 2018).
Ultrasound Extraction and Solid-Phase Extraction
Liu et al. (2018) proposed a combined technique for the extraction of different
classes of natural products (phenolics, terpenoids, and phenolic acids) from
G. biloba leaves and ginsenosides from P. ginseng leaves. Six different natural deep
eutectic solvents were tested (Table 6.10). The presence of natural deep eutectic
solvent caused severe tailing of spots in high-performance thin-layer chromatography analysis; therefore, it was important to recover the analytes from natural deep
eutectic solvent before analysis. Hence, solid-phase extraction method was
employed using polymeric reversed-phase sorbent cartridges. Of the natural deep
eutectic solvents, choline chloride/malic acid (1:1 molar ratio) and glycerol/proline/
sucrose (1:1:1 molar ratio) were the best for G. biloba leaves, and choline chloride/
malic acid (1:1 molar ratio) and glucose/malic acid (1:1 molar ratio) for P. ginseng
leaves showing the highest yields of the target compounds. The addition of water to
natural deep eutectic solvent affected the extraction and maximum yields. The latter
were obtained with approximately 20% water (w/w). Results showed that the yield
of analytes obtained with the natural deep eutectic solvent is similar to that of methanol. A high advantage of the usage of natural deep eutectic solvent is their incapability to extract ginkgolic acids (considered very toxic to human) due to their low
polarity and low dissolution in natural deep eutectic solvents. This method proved
to be able to deliver reproducible chemical profiles from the natural deep eutectic
solvent extracts (Liu et al. 2018).
L. Nakhle et al.
Deep Eutectic Solvent-Based Vortex Extraction Combined
with Emulsification Liquid-Liquid Microextraction
Aydin et al. (2018) developed a new technique using deep eutectic solvent (choline
chloride/phenol 1:4 molar ratio) as a water-miscible extraction solvent for the
extraction of curcumin (Fig. 6.14). Recoveries of curcumin using different deep
eutectic solvent were above 96% (Aydin et al. 2018).
Dispersive Solid-Phase Extraction in Combination with Deep Eutectic
Solvent-Based Air-Assisted Liquid-Liquid Microextraction
The proposed method is represented in Fig. 6.15. The process started with dispersive solid-phase extraction method. Then air-assisted liquid-liquid microextraction
method was applied. In the proposed method, the synthesized deep eutectic solvent
was used as an elution/extraction solvent. Results showed many advantages such as
good repeatability, high enrichment factors and extraction recoveries, low limits of
detection and limits of quantification, and simplicity of operation. According to
Mohebbi et al. (2018), this method can be used for the routine analysis of many
drugs in the pharmaceutical and clinical laboratories with no harm on human health
and environment (Mohebbi et al. 2018).
Ultrasound Extraction and Solid-Phase Extraction
Liu et al. (2018) proposed a combined technique for the extraction of different
classes of natural products (phenolics, terpenoids, and phenolic acids) from
G. biloba leaves and ginsenosides from P. ginseng leaves. Six different natural deep
eutectic solvents were tested (Table 6.10). The presence of natural deep eutectic
solvent caused severe tailing of spots in high-performance thin-layer chromatography analysis; therefore, it was important to recover the analytes from natural deep
eutectic solvent before analysis. Hence, solid-phase extraction method was
employed using polymeric reversed-phase sorbent cartridges. Of the natural deep
eutectic solvents, choline chloride/malic acid (1:1 molar ratio) and glycerol/proline/
sucrose (1:1:1 molar ratio) were the best for G. biloba leaves, and choline chloride/
malic acid (1:1 molar ratio) and glucose/malic acid (1:1 molar ratio) for P. ginseng
leaves showing the highest yields of the target compounds. The addition of water to
natural deep eutectic solvent affected the extraction and maximum yields. The latter
were obtained with approximately 20% water (w/w). Results showed that the yield
of analytes obtained with the natural deep eutectic solvent is similar to that of methanol. A high advantage of the usage of natural deep eutectic solvent is their incapability to extract ginkgolic acids (considered very toxic to human) due to their low
polarity and low dissolution in natural deep eutectic solvents. This method proved
to be able to deliver reproducible chemical profiles from the natural deep eutectic
solvent extracts (Liu et al. 2018).
L. Nakhle et al.