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A novel method based on acid–base-induced cloud point extraction (AB-CPE) and magnetic solid-phase extraction (MSPE) coupled with high performance liquid chromatography (HPLC) for extraction and purification of 3-acetyl-2,5-dimethylthiophene (ADP) in the fast food noodle samples was established for the first time. In MSPE-AB-CPE, Fe3O4@SiO2 nanoparticles are used to purify samples, medium-chain saturated fatty acids (n-octanoic acid), and nonionic surfactant (TMN-6) were investigated as a pH-dependent phase based on acid–base reaction caused solely by adjusting pH. The calibration curves demonstrated linearity in the range 0.5–100 µg mL−1 (R2 = 0.9969), with relative recoveries (95.7–101.2%) and relative standard deviations (2.6–4.8%, n = 5). [ABSTRACT FROM AUTHOR]

Medium pressure liquid chromatography and semipreparative high-performance liquid chromatography, followed by recycling high-performance liquid chromatography, were used for the isolation and purification of oligostilbenes from the acetone extracts ofDipterocarpus semivestitusandNeobalanocarpus heimii. Two stilbene dimers, ε-viniferin andcis-ε-viniferin, and a stilbene trimer,cis-miyabenol C were isolated fromD. semivestitus. A trimer, ampelopsin C, and two tetramers, hemsleyanol D and isohopeaphenol, were isolated fromN. heimii. The purities of the compounds were determined by an ultrahigh-performance liquid chromatography. [ABSTRACT FROM PUBLISHER]

Radix isatidishas been widely used as a Chinese traditional medicine for its antivirus and anticancer activities where the minor components may contribute to these beneficial pharmaceutical effects. In order to enrich the target minor compounds effectively and rapidly, extraction, medium-pressure liquid chromatography (MPLC), high-speed countercurrent chromatography (HSCCC), and preparative high-performance liquid chromatography (pre-HPLC) were integratively used for separation and purification of two target minor compounds indole-3-acetonitrile-6-O-β-D-glucopyranoside (target 1) and clemastanin B (target 2) in the present study.Radix isatidiswas dried, pulverized, and extracted with 50% methanol at room temperature, then concentrated, and subjected to pretreatment with D-101 macroporous resin chromatography and extraction by MPLC. The first target compound was separated by MPLC at the purity raised to 70–80%, but without the second minor compounds which were irreversibly adsorbed by C18 solid support. Therefore, the second target compound in the crude extract was directly separated by HSCCC at a purity of 80–90%. Finally, these refined samples were further separated by pre-HPLC to obtain a high purity at 98–99%. The chemical structure identification of each target compound was carried out by infrared radiation (IR), electrospray ionization mass spectrometry (ESI-MS), and1H-NMR. [ABSTRACT FROM AUTHOR]

Forsythoside A and suspensaside A were isolated and purified fromForsythia suspensaby one step of high-speed counter-current chromatography for the first time using a solvent system of ethyl acetate-n-butanol-methanol-water (4:0.5:0.5:5,v/v). The purities of the two compounds were 98.19% and 98.05%, respectively, as determined by HPLC. Their structures were identified by MS, UV, and NMR analysis. Such a simple and effective method was fairly useful to prepare pure compounds as reference substances for related study onForsythia suspensa. [ABSTRACT FROM PUBLISHER]

The present study describes an efficient hyphenated flash chromatographic (FC) for the purification of coumarins and polymethoxy flavones (PMF's) from cold pressed grapefruit peel oil (GFO), a byproduct from citrus juice processing plant. GFO was subjected to silica column chromatography using sequential isocratic elution by hexane and chloroform to separate the waxes and phytochemicals enriched fractions, respectively. The chloroform extract was used for hyphenated FC separation using a gradient mobile phase of hexane and acetone. The peak separations were monitored at dual wavelengths of λ210 nm and λ340 nm. The individual fractions were analyzed by HPLC, pooled and concentrated resulting in isolation of two coumarins (auraptene and bergapten) and three PMF's (tangeretin, heptamethoxyflavone, and nobiletin). The purity and identity of the isolated compounds was confirmed by spectral analysis using high performance liquid chromatography, matrix-assisted laser desorption/Ionization-time of flight-mass spectrometry, and nuclear magnetic resonance. The hyphenated FC separation method was further validated by test of repeatability resulting in low RSD for the yield of the phytochemicals. Utilization of the developed separation method for isolation of value added products from grapefruit byproducts could be beneficial to the citrus processing industry.Supplemental materials are available for this article. Go to the publisher's online edition ofSeparation Science & Technologyto view the supplemental file. [ABSTRACT FROM PUBLISHER]

A 17-run Box-Behnken design (BBD) with three factors was used to improve the conditions for extracting astaxanthin from shrimp waste. The astaxanthin level was determined by high performance liquid chromatography (HPLC) using a C18column and a UV detector at 476 nm. The mean extraction yield of astaxanthin at the improved conditions (extraction time 1.4 h, extraction temperature 72.4°C, and liquid-solid ratio 27.3) was 98.7 ± 2.6 µg g−1. A solid-phase extraction (SPE)-HPLC method was developed with a new hybrid organic-inorganic hybrid monolith for further purification of astaxanthin from shrimp waste. The SPE recoveries were ranging from 81.3 ± 2.4% to 86.5 ± 3.3%, and the intra-day and inter-day relative standard deviations (RSDs) of the proposed method were less than 4.3 ± 0.5% and 4.8 ± 0.2%, respectively. BBD increased the extraction efficiency and shortened extraction times significantly. SPE-HPLC with hybrid monolith showed good selectivity and purified astaxanthin from shrimp waste. [ABSTRACT FROM PUBLISHER]

An effective high–speed counter–current chromatography (HSCCC) method was established for semi-preparative isolation and purification of bioactive chemical constituents from the Tibetan medicinal plantPedicularis longifloravar.tubiformis(Klotzsch) P. C. Tsoong. With a two-phase solvent system composed of chloroform–methanol–water (8:4:5, v/v), 40 mg of extract was separated to yield luteolin (12.5 mg), apigenin (9.6 mg), and chrysoeriol (4.8 mg), with purities of 99.3, 98.2, and 98.6%, respectively, as determined by high-performance liquid chromatography (HPLC). The chemical structures of these three components were identified by1H NMR and13C NMR. [ABSTRACT FROM PUBLISHER]

In this study, a preparative high performance centrifugal partition chromatography (CPC) method for isolation and purification of the bioactive component astilbin from the crude extract ofSmilax glabrawas successfully established by usingn-hexane-ethyl acetate-methanol-water as the two-phase solvent system. The upper phase ofn-hexane-ethyl acetate-methanol-water (1:10:1:10, v/v) was used as the stationary phase of CPC. Under the optimum conditions, 88 mg of astilbin at 98.5% purity, as determined by HPLC, was yielded from 500 mg of the crude extract in a single CPC separation. The peak fraction of CPC was identified by1H NMR and13C NMR. [ABSTRACT FROM AUTHOR]

The detrimental effect of heterogeneity on the efficiency of particle packed columns has been a long standing issue in chromatographic separations. This heterogeneity arises from the difference in packing density between the wall and central regions of the chromatographic bed and imparts radial variance in mobile phase velocity through the column. In conjunction with the uneven distribution of the sample band through frits and distributors at the head of the column, the resultant effect is a decrease in efficiency due to the formation of a parabolic-“like” sample band. We introduce the concept of “Active Flow Management” to counteract the effects of column heterogeneity via the separation of the flow eluting from the center of the column from that of the flow eluting near the peripheral wall region. The flow streams from the two aforementioned regions are separated by the use of a specialized column outlet fitting. By varying the ratio of flow eluting from the center to the peripheral region it was possible to increase the efficiency of a 100 × 21 mm column by up to 57% compared to a column operated in the conventional manner. [ABSTRACT FROM AUTHOR]

Reversed phase-high performance liquid chromatography (RP-HPLC) was used to analyze fucoxanthin content of two species of Malaysian brown seaweeds,Turbinaria turbinate, andSargassum plagyophyllum. The fucoxanthin contents ofT. turbinataandS. plagyophyllumwere 0.59 ± 0.08 and 0.71 ± 0.01 mg/g dry-weight, respectively. Ultraviolet spectrum of fucoxanthin showed the maximum absorbance at 450 nm. Furthermore, the HPLC chromatograms of purified all-trans-fucoxanthin from showed one major peak with a retention time of 7.8 min. [ABSTRACT FROM AUTHOR]

In this study, a simple, rapid, and efficient purification method of five major flavonoids from crudeFlaveria bidentisextracts was established. Five flavonoids components were initially obtained by ethanol-water extraction ofFlaveria bidentis(L.) Kuntze, followed by using D4020 resin-based column chromatography and semi-preparative high performance liquid chromatography. 9.3 mg hyperoside, 6.5 mg patuletin-3-O-glucoside, 1.7 mg isorhamnetin 3-sulphate, 8.4 mg astragalin, and 4.9 mg 6-methoxykaempferol-3-O-galactoside at high purity of over 94% were obtained from 580 mgFlaveria bidentisextracts. This method is more efficient than HSCCC comparing with the results of these two methods regarding analysts’ purity, recovery, and running time. [ABSTRACT FROM PUBLISHER]

In order to isolate large amounts of pure lutonarin and saponarin, a high performance method for isolation and purification of these two flavonoids from barley (Hordeum vulgare) seedlings was successfully established by utilizing high-speed counter-current chromatography (HSCCC). Separation was performed with a two-phase solvent system: ethyl acetate/n-butanol/water (3:2:5, v/v/v). A total of 24 mg lutonarin and 14 mg saponarin was obtained in one-step separation from 100 mg sample. High performance liquid chromatography (HPLC) analysis showed that the purity of each of the two compounds was over 98%. Their chemical structures were confirmed by UV, 1H NMR, and 13C NMR data. [ABSTRACT FROM AUTHOR]

A centrifugal partition chromatography (CPC) was applied to separate and purify flavonoids from the extract of Pterocarpus santalinus. Three flavonoids, taxifolin (21 mg), dihydrokaempferol (18 mg), and naringenin (16 mg) were successfully separated from 500 mg of ethyl acetate fraction of P. santalinus using centrifugal partition chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) in single CPC run. Eryodictyol (8 mg) and quercetin (5 mg) were further purified by HPLC. The purities of the isolated compounds were determined to be over 90% by HPLC analysis and their structures were elucidated by 1H NMR, 13C NMR, and ESI-MS. [ABSTRACT FROM AUTHOR]

Semi-preparative high-speed countercurrent chromatography (HSCCC) was successfully performed for isolation and purification of caffeic acid and 4 bioactive flavonoids from Eupatorium adenophorum Spreng using stepwise elution with a pair of two-phase solvent systems composed of ethyl acetate–methanol–water at the volume ratios of 10:1:10 and 5:1:5 (v/v). From 378.5 mg of crude extract 24.1 mg of caffeic acid, 6.7 mg of 4′-methyl quercetagetin 7-O-(6″-O-E-caffeoylglucopyranoside), 6.5 mg of quercetagetin 7-O-(6″-O-acetyl-β-D-glucopyranoside), 31.8 mg of eupalitin 3-O-β-D-galactopyranoside, and 36.7 mg of eupalitin were obtained with purities of 96.0%, 91.2%, 82.3%, 95.1%, and 85.6%, respectively. The structures of the separated compounds were identified by EI-MS, FAB-MS, 1HNMR, and 13CNMR. [ABSTRACT FROM PUBLISHER]

We used a novel approach to purify Pleurotus ostreatus laccase using the three phase partitioning (TPP) methodology. The aim of our research was to study the effect of TPP parameters on laccase purity and yield. The response surface methodology (RSM) has been applied to design the experiments to evaluate the interactive effects of the three most important operating variables: ammonium sulphate saturation (w/v) (20-80%), ratio of crude extract to t-butanol (v/v) (1:1 to 1:3), and temperature (20-60°C). Using this methodology, the optimum values for the critical components were obtained as follows: ammonium sulphate saturation (w/v), 50-60%; ratio of crude extract to t-butanol (v/v) 1.0:1.8; temperature 42-45°C, respectively. Under optimal conditions, the experimental laccase yield and purity was 184% and 7.22-fold, respectively. SDS-PAGE and RP-HPLC revealed that the laccase was purified by TPP. The determination coefficients (R2) were 0.9891 and 0.9728 for laccase purity and yield, respectively, indicating an adequate degree of reliability in the model. To our knowledge, the present work demonstrates for the first time the successful application of RSM to TPP. [ABSTRACT FROM AUTHOR]

The commercial value of phenols is often reduced due to the presence of colored impurities. Several conventional techniques have been used for the purification of phenols. However, conventional purification techniques are tedious and make use of hazardous and expensive organic solvents. In this study, we present a new method for purification of an aged-discolored (orange) commercial 2,3-dimethyl phenol (2,3-DMP) reagent (∼97%) using supercritical fluid CO2 (SCF CO2), as an extraction solvent. A supercritical fluid extraction (SFE)/purification apparatus was constructed and purification of the reagent under different extraction conditions was investigated. Based on the differential solubility of the 2,3-DMP and the impurities in SCF CO2, the commercial reagent was successfully purified by SFE; the purified 2,3-DMP was a white solid of high purity (>99.5%). The SFE method was also applied to purify a recently purchased batch of 2,3-DMP reagent. We found that the reagent purified by SFE was of a higher quality than a commercially available analytical standard. [ABSTRACT FROM AUTHOR]

A novel, rapid, and high efficiency method to purify natural punicalagin by preparative HPLC is described. The optimum purification condition for punicalagin purification was 14% methanol in 0.1% trifluoroacetic acid solution as the mobile phase. The flow rate was 12 ml/min. 81.7 mg punicalagin at 98.05% purity was obtained from 300 mg crude extract containing 30% punicalagin. The stability of purified punicalagin was also studied. Heating, solar radiation, the pH value, and a strong oxidizer decreased its stability in water. Fe3+ and Cu2+ were complexed by punicalagin. Punicalagin was stable with ultrasonication, ultraviolet radiation, and commonly used food and cosmetic additives. [ABSTRACT FROM AUTHOR]

A new HPLC-DAD method has been developed to identify and quantify free microcystins (MC) in biological samples from fish (intestine and liver). The toxins were extracted from 500 mg sample with a mixture of methanol-water (85 : 15, v/v) and the extracts obtained were purified employing immunoaffinity columns (IAC). The purification step was optimised by a full factorial 32 design. MC were separated using conventional C18 column and an acetonitrile-acidified water (pH 3) gradient. Detection and quantification limits resulted equal for the two toxins assayed (MC-RR and MC-LR) and were 0.15 and 0.5 µg g-1, respectively. The accuracy for each MC in liver samples were 96% (range 80-113%) for MC-RR and 101% (range 93-118%) for MC-LR. The results were slightly lower for intestine samples, with recoveries ranging between 85% (75-93%) for MC-RR and 88% (80-97%) for MC-LR. The proposed method was applied for the determination of free MC in fish intoxicated with these toxins, in order to determine its utility to evaluate the potential risks for human health if MC-contaminated fish are consumed. The results showed the transference of MC-LR from cyanobacterial cells to fish tissues. [ABSTRACT FROM AUTHOR]

Normal-phase preparative HPLC was applied to the purification of nitrendipine and its dimethyl ester from raw materials. For each separation, the chromatographic conditions were optimized by adjusting the sample size to achieve an efficient purification with a yield of 99% in the shortest time. The contaminating impurities were removed in a single step by preparative chromatography. This work demonstrates how gram quantities of analytically pure materials can be conveniently obtained using preparative HPLC. [ABSTRACT FROM AUTHOR]