Single-drop liquid-phase microextraction for the determination of hypericin, pseudohypericin and hyperforin in biological fluids by high performance liquid chromatography

Ionic liquid-based dispersive liquid-liquid microextraction of anthelmintic drug residues in small-stock meat followed by LC-ESI-MS/MS detection

An ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) of 20 anthelmintic drugs followed and detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed, optimized, and validated. The parameters affecting the anthelmintic extraction efficiencies such as selection of extraction solvent (ionic liquids), selection of disperser solvent, volume of extraction solvent, volume of disperser solvent, pH of the aqueous phase, extraction time, salt addition, and centrifugation time were optimized. Validation was conducted according to ISO/IEC 17025:2017 and Commission Implementing Regulation (EU) 2021/808 of 22 March 2021. Validation parameters such as calibration function, matrix effect, limit of detection (LOD), limit of quantification (LOQ), decision limit (CCα), accuracy, and precision were established. Coefficient of determination (R 2) values ranging from .99938 to .99995 were obtained using the matrix calibration curve spiked at 0, 0.25, 1.0, 1.5, and 2.0 times MRL. The LODs and LOQs were calculated using the standard deviation of the response and the slopes of the calibration curves ranged from 0.35 to 26.1 μg/kg and from 1.2 to 87.0 μg/kg, respectively, and were dependent on calibration range. The CCα values ranged from 23 to 1022.0 μg/kg and are also dependent on the MRL concentration levels. The coefficient of variation (CV) values calculated are within the reproducibility range of 16%-30% adapted from the Horwitz Equation CV = 2(1-0.5 log C) and ranged from 1.7% to 16.9%. The developed and validated and the standard QuEChERS method were compared. The IL-DLLME LC-MS/MS method was applied to 32 small stock (18 caprine [goat] and 14 ovine [sheep]) liver samples received from municipal abattoirs at Botswana National Veterinary Laboratory for the analysis of anthelmintic drug residues. The results obtained indicated that the anthelmintic drug residues were all below the detection capability, and therefore, the samples were passed as fit for human consumption.

Hyperforin: A natural lead compound with multiple pharmacological activities

Hypericum perforatum L. (Clusiaceae), commonly known as St. John's wort, has a rich historical background as one of the oldest and most widely studied herbal medicines. Hyperforin is the main antidepressant active ingredient of St. John's wort. In recent years, hyperforin has attached increasing attention due to its multiple pharmacological activities. In this review, the information on hyperforin was systematically summarized. Hyperforin is considered to be a lead compound with diverse pharmacological activities including anti-depression, anti-tumor, anti-dementia, anti-diabetes and others. It can be obtained by extraction and synthesis. Further pharmacological studies and more precise detection methods will help develop a value for hyperforin. In addition, structural modification and pharmaceutical preparation technology will be beneficial to promoting the research progress of hyperforin based innovative drugs. Although these works are full of known and unknown challenges, researchers are still expected to make hyperforin play a greater value.

Extraction and pre-concentration of parabens in liquid pharmaceutical samples by dispersive liquid-liquid microextraction based on deep eutectic solvents

In this paper dispersive liquid-liquid microextraction using deep eutectic solvent (DES), as an extraction solvent, was applied for the pre-concentration and determination of parabens in liquid pharmaceutical samples. A DES composed of a hydrogen bond acceptor [choline chloride (ChCl)] and a hydrogen bond donor (glucose) achieved the highest extraction efficiency. Therefore, this solvent was selected as the extraction solvent. After the synthesis of this solvent, its various properties were investigated. Thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy were used for this purpose and the successful synthesis of the solvent was confirmed. HPLC with photodiode array detection was used for the analysis of paraben species. Parameters affecting the extraction efficiency were monitored and optimized through univariate analysis and experimental design. Under the optimal conditions (pH of aqueous solution 4.5, ethanol as the disperser solvent, and glucose DES as the extraction solvent), the linearity range of 0.1-5000 ng mL^-1 was obtained with the coefficient of determination (R² ) between 0.993 and 0.9962. Limits of detections ranged from 0.04 to 0.15 ng mL^-1 , with relative standard deviations from 1.8% to 6.8%. The developed method was applied to the determination of parabens in liquid pharmaceuticals such as ampule, syrups, and nose drop samples. A certain amount of paraben was added to the tested real samples to increase their shelf life. The relative recoveries in these real samples ranged between 80.9% and 103.1%.

Natural Products for the Treatment of Drug Addiction: Narrative Review

Drug addiction is considered a chronic disorder affecting the individual's life, his/her family and society. Up till now the treatment of drug addiction is considered a problematic issue. Synthetic drugs available for the treatment of drug addiction are few, of limited efficacy and associated with serious side effects. Therefore, there is a continuous search for better therapeutic agents for drug addiction. Natural products represent a promising source for drug addiction treatment. This review summaries drug addiction definition, its mechanism of action, its types, its diagnosis, factors affecting its development and different available approaches for its treatment especially the use of natural products. Six plants were discussed thoroughly in this review, including, Tabernanthe iboga Baill., Mitragyna speciosa Korth., Pueraria montana var. lobata (Willd.) Sanjappa & Pradeep, Hypericum perforatum L., Panax ginseng C.A. Mey., and Withania somnifera (L.) Dunal.

Derivatization-free multi-step extraction for trace haloacetic acids analysis with ion chromatography: Performance and mechanisms

Haloacetic acids (HAAs) are a type of disinfection byproducts commonly found in drinking water with carcinogenic, mutagenic, or teratogenic risks to humans. Currently, the analytical methods of trace HAAs are either labor-intensive or very expensive. We herein propose a facile multiple-step extraction strategy for HAAs analysis with common ion chromatography (IC). This study is based on a fundamental water chemistry principle that HAAs become protonated featuring positive logK_ow values (> 0.34) under pH < pK_a but deprotonated featuring negative logK_ow values (< -2.37) under pH > pK_a. By taking advantage of the species and property switches, HAAs can be extracted and enriched into methyl tert-butyl ether first at pH < 0.5 and then back-extracted into neutral water and enriched again. Equally important, interfering anions in IC chromatogram are eliminated because they have negative logK_ow values. Verification results show that HAAs were enriched by 11.4 times in average while interfering anions were almost eliminated (> 99%). Although similar to USEPA Method 552.3 in method detection limits (0.033-0.246 μg/L), recoveries (70%~110%), and relative standard deviations (< 9.91%), this method took ≤ 70 min to run a batch of samples without derivatization, which takes over 2 h. The methodology may be applicable to other pollutants that also have contrasting K_ow values at different pH.

Plant tissue culture as a perpetual source for production of industrially important bioactive compounds

Plants have been used throughout the world for its medicinal powers since ancient time. The pharmacological properties of plants are based on their phytochemical components especially the secondary metabolites which are outstanding sources of value added bioactive compounds. Secondary metabolites have complex chemical composition and are produced in response to various forms of stress to perform different physiological tasks in plants. They are used in pharmaceutical industries, cosmetics, dietary supplements, fragrances, flavors, dyes, etc. Extended use of these metabolites in various industrial sectors has initiated a need to focus research on increasing the production by employing plant tissue culture (PTC) techniques and optimizing their large scale production using bioreactors. PTC techniques being independent of climatic and geographical conditions will provide an incessant, sustainable, economical and viable production of secondary metabolites. This review article intends to assess the advantages of using plant tissue culture, distribution of important secondary metabolites in plant families, strategies involved for optimal metabolite production and the industrial importance of selected secondary metabolites.

Double salting-out effect assisted heat-shrinkable tubing liquid phase microextraction followed by high performance liquid chromatography for determination of flavonoids in human plasma

This paper proposed a double salting-out effect assisted heat-shrinkable tubing liquid phase microextraction (LPME). In the study, a low price and handy heat-shrinkable tubing was used as carrier of extraction solvent and salt film, which was placed in sample solution containing certain concentration of salt for concentrating and enriching flavonoids from human plasma. Through the double salting-out effect in different regions, this microextraction method has a good present to enhance the extraction efficiency and enrichment factors of the target analytes. Several key parameters affecting the extraction efficiency were investigated, including the type of extraction solvent, the occurring region of salting-out effect, salt concentration, pH of sample phase, stirring rate, extraction time, and volume of sample phase. Also, the mechanism of the procedure was described. Under the optimum conditions, excellent linearities with r≥ 0.9912 were obtained, the limits of detection were 2.5-150 ng/mL, the average recoveries ranged from 90.3% to 111.2%. In the new procedure, the low-cost and stable heat-shrinkable tubing was first used as carrier in LPME, combined with high performance liquid chromatography (HPLC), has been successfully applied for the determination of the trace-level target analytes in human plasma.

Quality control of Hypericum perforatum L. analytical challenges and recent progress

Objectives

The most widely applied qualitative and quantitative analytical methods in the quality control of Hypericum perforatum extracts will be reviewed, including routine analytical tools and most modern approaches.

Key findings

Biologically active components of H. perforatum are chemically diverse; therefore, different chromatographic and detection methods are required for the comprehensive analysis of St. John's wort extracts. Naphthodianthrones, phloroglucinols and flavonoids are the most widely analysed metabolites of this plant. For routine quality control, detection of major compounds belonging to these groups seems to be sufficient; however, closer characterization requires the detection of minor compounds as well.

Conclusions

TLC and HPTLC are basic methods in the routine analysis, whereas HPLC-DAD is the most widely applied method for quantitative analysis due to its versatility. LC-MS is gaining importance in pharmacokinetic studies due to its sensitivity. Modern approaches, such as DNA barcoding, NIRS and NMR metabolomics, may offer new possibilities for the more detailed characterization of secondary metabolite profile of H. perforatum extracts.

Pre-concentration and determination of amitriptyline residues in waste water by ionic liquid based immersed droplet microextraction and HPLC

This paper describes a new approach for the determination of amitriptyline in wastewater by ionic liquid based immersed droplet microextraction (IL-IDME) prior to high-performance liquid chromatography with ultraviolet detection. 1-Hexyl-3-methylimidazolium hexafluorophosphate ([C₆MIM][PF₆]) was used as an ionic liquid. Various factors that affect extraction, such as volume of ionic liquid, stirring rate, extraction time, pH of the aqueous solution and salting effect, were optimized. The optimal conditions were as follows: microextraction time, 10 min; stirring rate, 720 rpm; pH, 11; ionic drop volume, 100 μL; and no sodium chloride addition. In quantitative experiments the method showed linearity in a range from 0.01 to 10 μg/mL, a limit of detection of 0.004 μg/mL and an excellent pre-concentration factor (PF) of 1100. Finally, the method was successfully applied to the determination of amitriptyline in the hospital wastewater samples.

Microextraction techniques in therapeutic drug monitoring

Therapeutic drug monitoring (TDM), as part of clinical process of medical treatments, is commonly used to maintain 'therapeutic' drug concentrations. TDM is useful to identify the causes of unwanted or unexpected responses, to prevent unnecessary diagnostic testing, to improve clinical outcomes, and even to save lives. The determination of drug concentration in blood samples requires an excellent sample preparation procedure. Recent trends in sample preparation include miniaturization, automation, high-throughput performance, on-line coupling with analytical instruments and low-cost operation through extremely low or no solvent consumption. Microextraction techniques, such as liquid- and solid-phase microextraction, have these advantages over the traditional techniques. This paper reviews the recent developments in microextraction techniques used for drug monitoring in serum, plasma or blood samples.

Liquid-phase microextraction in bioanalytical sample preparation

Liquid-phase microextraction (LPME) emerged in the mid-to-late 1990s, facing up to the main shortcomings of the classical liquid-liquid extraction. Since its origin, this new technique has been in continuous development driven by its successful and widespread use in the analytical sciences. Its inherent properties, such as low sample volume requirement, high preconcentration factors achieved and excellent sample clean-up, make LPME a very useful technique for bioanalytical sample preparation. This review focuses on the main LPME-related techniques, predominantly single-drop microextraction and supported hollow-fiber LPME, paying particular attention to the bioanalytical applications. A general view of the essential trends, including the description of promising extraction modes and solvents, is also highlighted.

Single-drop microextraction in bioanalysis

Bioanalysis usually requires a preparation procedure for sample cleanup or preconcentration. Conventional sample preparation techniques are often time consuming and labor intensive. Among recent progress in sample preparation, single drop microextraction (SDME) is one of the most efficient techniques providing both sample cleanup and preconcentration capabilities. In SDME, analytes are extracted from a sample solution into an acceptor drop and the drop is introduced to subsequent analysis. Since the volume of the acceptor drop is 1–10 µl or less, the consumption of solvents can be minimized and the preconcentration effect is enhanced. In this review, the basic principles of two-phase and three-phase SDME are described briefly and then recently developed modes of SDME, coupling with analytical instruments, and methods to enhance the drop stability are discussed. Recent applications of SDME to biological samples, including urine, blood and saliva, for the analysis of drugs, metal ions and biomarkers are reviewed.

Application of single-drop microextraction combined with in-microvial derivatization for determination of acidic herbicides in water samples by gas chromatography-mass spectrometry

A single-drop microextraction (SDME) method and gas chromatography with mass spectrometry detection have been developed for the determination of acidic herbicides in water. The analytes were extracted from a 3 mL sample solution using 4 microL of hexyl acetate. After extraction, derivatization was carried out inside a glass microvial (1.1mm i.d.) using pentafluorobenzyl bromide (PFBBr). Triethylamine (TEA) was used as the reaction catalyst. The influence of derivatization reagent volume, catalyst amount, derivatization time and temperature on the yield of the in-microvial derivatization was investigated. Derivatization reaction was performed using 0.3 microL of PFBBr and 0.4 microL of TEA (10%, v/v in toluene) at 100 degrees C during 5 min. Also, the effects of different experimental SDME parameters such as selection of organic solvent, sample pH, addition of salt, extraction time and temperature of extraction were studied. Analytical parameters such as enrichment factor, precision, linearity and detection limits were also determined. The enrichment factors were between 83 and 157. The limits of detection (LOD) were in the range 1.2-7 ng/L (S/N=3). The relative standard deviations obtained were below 10.1% (n=5).

Sample preparation

A panorama of sample preparation methods has been composed from 481 references, with a highlight of some promising methods fast developed during recent years and a somewhat brief introduction on most of the well-developed methods. All the samples were commonly referred to molecular composition, being extendable to particles including cells but not to organs, tissues and larger bodies. Some criteria to evaluate or validate a sample preparation method were proposed for reference. Strategy for integration of several methods to prepare complicated protein samples for proteomic studies was illustrated and discussed.

Determination of decabromodiphenyl ether in water samples by single-drop microextraction and RP-HPLC

This paper describes the development of a new method using single-drop microextraction (SDME) and RP-HPLC for the determination of decabromodiphenyl ether (BDE-209) in water samples. The effects of SDME parameters such as extraction solvent, microdrop volume, extraction time, stirring speed, salt concentration, and sample pH on the extraction performance are investigated. Under optimal extraction conditions (extraction solvent, toluene; solvent drop volume, 3.0 microL; extraction time, 15 min; stirring speed, 600 rpm; no addition of salt and change of sample pH), the calibration curve was drawn by plotting peak area against a series of BDE-209 concentrations (0.001-1 microg/mL) in aqueous solution; the correlation coefficient (r) was 0.9998. The limit of detection was 0.7 ng/mL. The enrichment factor was 10.6. The precision of this method was obtained by six successive analyses of a 100 ng/mL standard solution of BDE-209, and RSD was 4.8%. This method was successfully applied to the extraction of BDE-209 from tap and East Lake water samples with relative recoveries ranging from 92.5 to 102.8% and from 91.5 to 96.2%, respectively, and the relative standard deviations (n = 3) were 4.4 and 2.2%. The proposed method is acceptable for the analysis of BDE-209 in water samples.