[Surface-modified microchip electrophoretic separation and analysis of functional components in health care products].

Microchip electrophoresis (MCE) is widely applied in food, environment, medicine, and other fields, owing to its high separation efficiency, low consumption of reagents and samples, and ease of integrating multiple operating units. Polymer microchip materials like cycloolefin copolymer (COC) are low-cost and easy to fabricate. However, their practical applications are limited by the non-specific adsorption on channel surface during electrophoresis and the instability of electroosmotic flow. These shortcomings can be solved by COC surface modification. In this study, a static coating and dynamic/static coating combined strategy was used to develop a channel-surface-modified COC microchip. Combined with laser-induced fluorescence (LIF) detection, a MCE-LIF separation and analysis method was developed for detecting functional components in health care products. The separation performance of MCE was improved by the static coating microchannel surface modification method. The static coating was constructed by hydrophobic amino acid adsorption, glutaraldehyde immobilization, and hydrophilic amino acid functionalization on the COC microchannel surface. The separation performance of MCE was improved by microchannel surface modification combined with dynamic/static coating. The static coating was constructed by valine adsorption, carboxyl activation, and ethylenediamine functionalization on the COC microchannel surface. The dynamic coating is automatically formed by introducing a buffer solution containing hydroxypropyl methylcellulose and sodium dodecyl sulfate into the microchannel. The physical and chemical properties of surface-modified microchannels and the factors governing electrophoretic separation were studied. Combined with LIF detection, the MCE-LIF separation and analysis of lysine and γ-aminobutyric acid present in children's health care products, as well as aspartic acid and taurine in sport drinks, were developed. The recoveries of lysine and γ-aminobutyric acid in children's health care products were 84.8%-118%, and the relative standard deviations (RSDs) were less than 7.2% (n=3). The recoveries of aspartic acid and taurine in sport drinks were 97.5%-118%, and the RSDs were less than 6.4% (n=3). The analysis results are consistent with the HPLC results, and the method has potential for application in the separation and analysis of anionic amino acids in health care products.

[Advances in microchip electrophoresis for the separation and analysis of biological samples].

Microchip electrophoresis is a separation technology that involves fluid manipulation in a microchip; the advantages of this technique include high separation efficiency, low sample consumption, and fast and easy multistep integration. Microchip electrophoresis has been widely used to rapidly separate and analyze complex samples in biology and medicine. In this paper, we review the research progress on microchip electrophoresis, explore the fabrication and separation modes of microchip materials, and discuss their applications in the detection and analysis of biological samples. Research on microchip materials can be mainly categorized into chip materials, channel modifications, electrode materials, and electrode integration methods. Microchip materials research involves the development of silicon, glass, polydimethylsiloxane and polymethyl methacrylate-based, and paper electrophoretic materials. Microchannel modification research primarily focuses on the dynamic and static modification methods of microchannels. Although chip materials and fabrication technologies have improved over the years, problems such as high manufacturing costs, long processing time, and short service lives continue to persist. These problems hinder the industrialization of microchip electrophoresis. At present, few static methods for the surface modification of polymer channels are available, and most of them involve a combination of physical adsorption and polymers. Therefore, developing efficient surface modification methods for polymer channels remains a necessary undertaking. In addition, both dynamic and static modifications require the introduction of other chemicals, which may not be conducive to the expansion of subsequent experiments. The materials commonly used in the development of electrodes and processing methods for electrode-microchip integration include gold, platinum, and silver. Microchip electrophoresis can be divided into two modes according to the uniformity of the electric field: uniform and non-uniform. The uniform electric field electrophoresis mode mainly involves micro free-flow electrophoresis and micro zone electrophoresis, including micro isoelectric focusing electrophoresis, micro isovelocity electrophoresis, and micro density gradient electrophoresis. The non-uniform electric field electrophoresis mode involves micro dielectric electrophoresis. Microchip electrophoresis is typically used in conjunction with conventional laboratory methods, such as optical, electrochemical, and mass spectrometry, to achieve the rapid and efficient separation and analysis of complex samples. However, the labeling required for most widely used laser-induced fluorescence technologies often involves a cumbersome organic synthesis process, and not all samples can be labeled, which limits the application scenarios of laser-induced fluorescence. The applications of unlabeled microchip electrophoresis-chemiluminescence/dielectrophoresis are also limited, and simplification of the experimental process to achieve simple and rapid microchip electrophoresis remains challenging. Several new models and strategies for high throughput in situ detection based on these detection methods have been developed for microchip electrophoretic systems. However, high throughput analysis by microchip electrophoresis is often dependent on complex chip structures and relatively complicated detection methods; thus, simple high throughput analytical technologies must be further explored. This paper also reviews the progress on microchip electrophoresis for the separation and analysis of complex biological samples, such as biomacromolecules, biological small molecules, and bioparticles, and forecasts the development trend of microchip electrophoresis in the separation and analysis of biomolecules. Over 250 research papers on this field are published annually, and it is gradually becoming a research focus. Most previous research has focused on biomacromolecules, including proteins and nucleic acids; biological small molecules, including amino acids, metabolites, and ions; and bioparticles, including cells and pathogens. However, several problems remain unsolved in the field of microchip electrophoresis. Overall, microchip electrophoresis requires further study to increase its suitability for the separation and analysis of complex biological samples.

Depression and activities of daily living in elderly people applying for admission to public nursing facilities.

OBJECTIVE: The present study aims to (1) investigate the prevalence of positive screening for depression among elderly people applying for admission to public nursing facilities in Shenzhen and (2) to explore the correlation between depression and activities of daily living (ADL) among the elderly. METHODS: Visual and hearing acuity, ADL (obtained using the Barthel index), cognition and depression levels, and communication and social interaction skills were assessed in all elderly adults aged ≥60 years who applied for admission to public nursing facilities in Shenzhen between April 1, 2018, and December 31, 2019. RESULTS: A total of 1,113 elderly adults, 34.95% of whom were assessed as being depressed, were evaluated. Regarding dependence on the care of others, the ADL assessment results showed that 11.86% of the study subjects were fully dependent, 10.51% were severely dependent, 12.58% were moderately dependent, 42.86% were mildly dependent, and only 22.19% were fully capable of self-care. The univariate analysis suggested that gender, cognition level, visual and hearing acuity, and communication and social interaction skills were all correlated with the occurrence of depression. The prevalence of positive screening for depression was relatively high among subjects with an ADL score of ≤65; With an ADL score of ≤65, the prevalence of depression increased by 6% with every 1-point ADL score decrease. CONCLUSION: The prevalence of depression among elderly adults applying for admission to public nursing facilities in Shenzhen was high. For this reason, nursing facility caregivers should focus on screening elderly adults (especially subjects with impaired ADL function) for depression in order to improve their quality of life.

[Advance of Development and Application of GC-IR Technology].

The gas chromatograph (GC)-infrared spectroscopy (IR) technique combines the particular separating capacity of GC and the faultlessly with distinguishing capacity of molecular structure of IR, its detective sensitivity is very high and itis used to separate and identify many kinds of complicated compounds from element speciation analysis, natural products, and gasoline. This paper introduces the principle of GC-IR. Three types of interface techniques, light pipe technique, matrix isolation technique and direct deposition technique are compared. Connection type with other detections and factors influencing sensitivity in interface are also introduced. The improvement and achievement in coupling GC system, interface, data processing techniques and its application is reviewed in the present paper.

Separation and purification of steroidal saponins from Paris polyphylla by microwave-assisted extraction coupled with countercurrent chromatography using evaporative light scattering detection.

A method of microwave-assisted extraction coupled with countercurrent chromatography using evaporative light scattering detection was successfully developed for the separation and purification of steroidal saponins from Paris polyphylla. The main extraction conditions including microwave power, liquid/solid ratio, irradiation time, and extraction temperature were optimized using an orthogonal array design method. A suitable two-phase solvent system consisting of n-heptane/n-butanol/acetonitrile/water (10:19:6:20, v/v/v/v) was employed in the separation and purification of the extracts of P. polyphylla. A total of 7.1 mg polyphyllin VII, 4.3 mg gracillin, 9.2 mg dioscin, and 10.2 mg polyphyllin I were obtained from 1.5 g P. polyphylla in less than 300 min, the purities of which determined by HPLC were 96.7, 97.3, 98.7, and 98.6%, respectively. The identification and characterization of these compounds were performed by LC-ESI-MS and 1H NMR spectroscopy. The results demonstrated that the proposed method is feasible, economical and efficient for the extraction, separation and purification of effective compounds from natural products.

Microwave-assisted extraction coupled with countercurrent chromatography for the rapid preparation of flavonoids from Scutellaria barbata D. Don.

As a famous Chinese herb having good inhibitory effects on numerous human cancers both in vitro and in vivo, Scutellaria barbata D. Don attracts extensive attention worldwide. In this work, four flavonoids named scutellarin, baicalin, luteolin, and apigenin were simply and rapidly prepared from S. barbata by microwave-assisted extraction coupled to countercurrent chromatography. Extraction conditions including irradiation time, extraction temperature, liquid/solid ratio, and microwave power were optimized using an orthogonal array design method. The extract of S. barbata was separated and purified with a two-phase solvent system composed of hexane/ethyl acetate/methanol/acetic acid/water (1:5:1.5:1:4, v/v/v/v/v) and 4.5 mg of scutellarin, 4.6 mg of baicalin, 1.1 mg of luteolin, 2.1 mg of apigenin were obtained from 2.0 g original sample in a single run. The purities of scutellarin, baicalin, luteolin, and apigenin determined by HPLC were 93.6, 97.3, 97.6, and 98.4%, respectively. The targeted compounds were identified by LC with MS and (1) H NMR spectroscopy. The total time including extraction, separation, and purification was <300 min. Compared to traditional methods, microwave-assisted extraction coupled to countercurrent chromatography method is more simple and rapid for the extraction, separation, and purification of flavonoid compounds from natural products.

[Study on chemical constituents of triterpenoids from Potentilla discolor].

OBJECTIVE: To study the triterpenoids constituents in Potentilla discolor. METHODS: The compounds were isolated by silica gel chromatography, macroporous resins and polyamide column chromatography from the 70% ethanol extract, and their structures were identified by spectral analysis. RESULTS: Six compounds were obtained and their structures were identified as 3-O-beta-D-glucopyranosyl-(1 --> 2) -beta-D-xylopyranosyl-19a-hydroxyurs-12-en-28-acid (1), 2alpha, 3/beta, 19alpha-trihydroxyurs-12-en-28-acid (2), 3beta, 19alpha-trihydroxyurs-12-en-24, 28-acid (3), 2alpha, 3beta-dihydroxyolean-12-en-28-acid (4), 2alpha, 3alpha, 19alpha-trihydroxyurs-12-en-28-acid (5), beta-sitosterol (6). CONCLUSION: Compounds 1 and 3 are obtained from this plant for the fisrt time.

Evaluation of microwave-assisted extraction for aristolochic acid from Aristolochiae Fructus by chromatographic analysis coupled with nephrotoxicity studies.

In this paper, a microwave-assisted extraction (MAE) method was established for aristolochic acid-I from Aristolochiae Fructus, and the advantage of MAE was evaluated by chromatographic analysis coupled with nephrotoxicity studies. The experimental parameters of MAE for aristolochic acid-I in Aristolochiae Fructus were investigated and MAE was compared with Soxhlet extraction and ultrasound-assisted extraction in terms of extraction yields and extraction conditions. Under the optimum conditions, MAE could provide higher extraction yields of aristolochic acid-I (1.10 mg/g) than ultrasound-assisted extraction (0.82 mg/g) and Soxhlet extraction (0.95 mg/g), in addition to using less solvent and having a shorter extraction time. Furthermore, the nephrotoxicities of the extracts of Aristolochiae Fructus from different extraction procedures were investigated in Sprague-Dawley rats. The results of nephrotoxicity studies of, for example, general conditions, biochemistry parameters and histopathology examination showed no significantly differences in the nephrotoxicity levels of the extracts from MAE and that from Soxhlet extraction. These results indicated that MAE technique is a simple, rapid and effective extraction method, and the microwave irradiation during MAE procedure did not have any influence on the nephrotoxicity of Aristolochiae Fructus compared with Soxhlet extraction.

Ionic liquid aqueous solvent-based microwave-assisted hydrolysis for the extraction and HPLC determination of myricetin and quercetin from Myrica rubra leaves.

An ionic liquid aqueous solvent-based microwave-assisted hydrolysis (ILAS-MAH) approach was proposed for the rapid extraction and accurate determination of myricetin and quercetin from Myrica rubra (M. rubra) leaves for the first time. The effects of the ionic liquid class and concentration, liquid-solid ratio, hydrolysis temperature and time were investigated to obtain the optimal ILAS-MAH conditions. The optimized conditions were 2.0 mol/L [bmin][HSO4] or 2.5 mol/L acidified [bmin]Br solution, liquid-solid ratio 30:1 (mL : g), hydrolysis temperature 70°C and hydrolysis time 10 min. Under these conditions, the recoveries of myricetin and quercetin were in the range of 86.3-107.3% with relative standard deviation lower than 5.8%. Compared with conventional heating hydrolysis and regular MAH, the proposed approach reduced hydrolysis time and improved yields. The mechanism of ILAS-MAH was also investigated.

Evaluation of vacuum microwave-assisted extraction technique for the extraction of antioxidants from plant samples.

In the present work, vacuum microwave-assisted extraction (VMAE) was to perform microwave-assisted extraction in vacuum. Two well-known antioxidants, vitamin C from guava and green pepper, and vitamin E (alpha-tocopherol and gamma-tocopherol) from soybean and tea leaves, which were easy to be oxidized, were chosen as representative target compounds for the evaluation of VMAE. The extraction yields of vitamin C, alpha-tocopherol and gamma-tocopherol in VMAE and those in MAE performed in atmosphere (air-MAE) were compared and the effects of extraction time, extraction temperature and sample matrix were studied. Moreover, the effects of the oxygen and subpressure invacuo were also discussed via performed MAE in N(2) atmosphere (N(2)-MAE). The extraction yields of vitamin C, alpha-tocopherol and gamma-tocopherol in VMAE were higher than that in air-MAE, 35% increments of vitamin C from green pepper, 22% increments of alpha-tocopherol and 47% increments of gamma-tocopherol from tea leaves were obtained, respectively. The comparable increased extraction yields of vitamin C, alpha-tocopherol and gamma-tocopherol in N(2)-MAE to that in air-MAE confirmed that oxygen in system was the crucial factor for the oxidation of vitamin C and vitamin E, VMAE was beneficial for the extraction of these oxygen-sensitive compounds. In addition, the subpressure invacuo in the VMAE system also showed positive affect on the extraction yields. On the basis of preventing oxidation and improving extraction efficiency of target compounds because of less oxygen and subpressure invacuo in the extraction system, VMAE has good potential for the extraction of oxygen-sensitive and thermosensitive compounds from plant samples.

Application of ionic liquids in the microwave-assisted extraction of polyphenolic compounds from medicinal plants.

Ionic liquids (ILs) solutions as solvents were successfully applied in the microwave-assisted extraction (MAE) of polyphenolic compounds from medicinal plants. ILs, its concentration and MAE conditions were investigated in order to extract polyphenolic compounds effectively from Psidium guajava Linn. (P. guajava) leaves and Smilax china (S. china) tubers. The results obtained indicated that the anions and cations of ILs had influences on the extraction of polyphenolic compounds as well as the ILs with electron-rich aromatic pi-system enhanced extraction ability. Under the optimized conditions, the extraction yields of the polyphenolic compounds were in the range of 79.5-93.8% with one-step extraction, and meanwhile the recoveries were in the range of 85.2-103% with relative standard deviations (R.S.D.s) lower than 5.6%. Compared to conventional extraction procedures, the results suggested that the proposed method was effective and alternative for the extraction of polyphenolic compounds from medicinal plants. In addition, the extraction mechanisms and the structures of samples before and after extraction were also investigated. ILs solutions as green solvents in the MAE of polyphenolic compounds from medicinal plant samples showed a great promising prospect.

Study of vacuum microwave-assisted extraction of polyphenolic compounds and pigment from Chinese herbs.

Vacuum microwave-assisted extraction (VMAE), in which microwave-assisted extraction (MAE) was performed in vacuum, was specially designed and applied for the extraction of polyphenolic compounds and pigments from Chinese herbs. The extraction conditions including solid/liquid ratio, extraction time, extraction temperature and degree of vacuum were optimized. Subsequently, VMAE, MAE, and conventional heating reflux extraction (HRE) were evaluated with resveratrol and emodin extraction from Rhizma Polygoni Cuspidati, myricetin and quercetin extraction from Myrica rubra leaves, and safflomin A extraction from Flos Carthami. In addition, the different microstructures of those rhizome, leaf, and flower samples were investigated before and after extraction. It was obvious that the extraction yields of resveratrol, myricetin and safflomin A (thermosensitive compounds) with VMAE were higher than that with MAE or HRE by increments of 6.4-9.4% and 7.9-29.5%, respectively. In contrast, there was no obvious difference among the extraction yields for emodin and quercetin (thermo-stable compounds) with VMAE, MAE and HRE, except that the solvent consumption in VMAE was decreased. The results suggest that VMAE is a good alternative for the extraction of polyphenolic compounds and pigments, especially thermosensitive compounds, from Chinese herbs.

Application of ionic liquids in the microwave-assisted extraction of trans-resveratrol from Rhizma Polygoni Cuspidati.

In this paper, the application of 1-n-butyl -3-methylimidazolium-based ionic liquids aqueous solutions as solvents in the microwave-assisted extraction (MAE) technique was first developed for the extraction of trans-resveratrol from Rhizma Polygoni Cuspidati. 1-butyl-3-methylimidazolium bromide ([bmim]Br) solution was selected as solvent; the conditions of MAE including the size of sample, liquid/solid ratio, extraction temperature and time were optimized by means of an orthogonal design L(9)(3(4)). Under optimized conditions, the extraction yield value of trans-resveratrol was 92.8% in a one-step extraction. The recovery was in the range 93.7-103.2% with relative standard deviation lower than 3.0% by the proposed procedure. The method was applied to extract trans-resveratrol from several different region samples. On the basis of extraction solvent and time, the proposed extraction technique was a green, rapid and alternative technique to extract and analyze trans-resveratrol in Rhizma Polygoni Cuspidati samples.