Application of liquid‐phase microextraction to the analysis of plant and herbal samples

Abstract

Introduction: The analysis of plant and herbal samples is a challenging task for analytical chemists due to the complexity of the matrix combined with the low concentration of analytes. In recent years different liquid-phase microextraction (LPME) techniques coupled with a variety of analytical equipment have been developed for the determination of both organic and inorganic analytes. Objective: Over the past few years, the number of research papers in this field has shown a markedly growing tendency. Therefore, the purpose of this review paper is to summarise and critically evaluate research articles focused on the application of LPME techniques for the analysis of plant and herbal samples. Results: Due to the complex nature of the samples, the direct application of LPME techniques to the analysis of plants has not often been done. LPME techniques as well as their modalities have been commonly applied in combination with other pretreatment techniques, including a solid-liquid extraction technique supported by mechanical agitation or auxiliary energies for plant analysis. Applications and the most important parameters are summarised in the tables. Conclusion: This review summarises the application of the LPME procedure and shows the major benefits of LPME, such as the low volume of solvents used, high enrichment factor, simplicity of operation and wide selection of applicable detection techniques. We can expect further development of microextraction analytical methods that focus on direct sample analysis with the application of green extraction solvents while fully automating procedures for the analysis of plant materials.

Assessment of Phytotoxins Using Different Technologies

“…Quantitative analytical methods are available for isolation, identification, and detection of phytotoxins. A specific extraction and isolation method was developed for enhancing the efficiency of phytotoxin analysis [71]. Table 1 presents various successful analytical techniques developed to analyze and detect phytotoxins from different plant species.…”

Solid‐phase adsorption methodologies of naturally occurring anthraquinones: A review

“…A similar pattern was also recorded for the overall anthraquinone content of a plant extract, leaving other pharmacologically active components of the same class, like stilbenes (recovery > 90%), unaffected, as they remained in the extractive solution. Furthermore, after extensive washing of the solid material first with MeOH-CH 3 COOH (8:2) first and then with 70% MeOH in H 2 O and recycling, the adsorption capacities of the polymer obtained by Liu and coworkers after five cycles was 96.1% for emodin (1) and 95.44% for physcion (3).…”

“…The most recent acquisition in the field of coated magnetic nanoparticles was that reported by X. Zhou and coworkers. 23 These authors described (1) the synthesis of a magnetic octahedral Fe(III)organic framework having 2-aminoterephthalic acid as the ligand of the metal center named Fe 3 O 4 @NH2-MIL-101(Fe) and ( 2) its application to the adsorption of aloe-emodin (6), emodin (1), and physcion (3) in rhubarb extracts. After structural characterization, this novel sorbent exhibited a large specific surface area of 259.2 m 2 /g with an average pore size of 6.0 nm and a high magnetic responsivity of From the literature survey reported above, it is evident how coated magnetic nanoparticles have found wide use for SPE of anthraquinones from different vegetable sources.…”

“…These include phenolic acids, flavonoids, alkaloids, terpenes, and steroids, among others, as excellently recently reviewed. [2][3][4][5][6][7] Quite surprisingly, despite their valuable, well-known reported pharmacological activities, 8 the employment of both SPE and SPA for the purification, isolation, and extraction/enrichment of naturally occurring anthraquinones is limited to a relatively low number of cases. Therefore, the aim of this review article is to provide a detailed survey of the SPE and SPA methodologies for the extraction of this important class of natural products reported so far and to discuss and propose future directions in this intriguing field of research.…”

Rapid Identification of Common Secondary Metabolites of Medicinal Herbs Using High-Performance Liquid Chromatography with Evaporative Light Scattering Detector in Extracts

“…Triterpenes such as lupeol, betulinic acid, betulin, ursolic acid and oleanolic acid and sterols such as stigmasterol and β-sitosterol are found commonly in plants. Among flavonoids, quercetin, rutin, kaempferol, apigenin, and taxifolin (dihydroquercetin) have been reported as the most commonly present secondary metabolites in plants [ 17 , 18 , 19 , 20 , 21 , 22 ]. For the analysis of triterpenes and sterols, gas chromatography is commonly employed [ 23 , 24 ].…”