Dioscin-induced apoptosis of human LNCaP prostate carcinoma cells through activation of caspase-3 and modulation of Bcl-2 protein family.

Dioscin is a natural steroid saponin derived from several plants, showing potent anti-cancer effect against a variety of tumor cell lines. In the present study, we investigated the anti-cancer activity of dioscin against human LNCaP cells, and evaluated the possible mechanism involved in its antineoplastic action. It was found that dioscin (1, 2 and 4 µmol/L) could significantly inhibit the viability of LNCaP cells in a time- and concentration-dependent manner. Flow cytometry revealed that the apoptosis rate was increased after treatment of LNCaP cells with dioscin for 24 h, indicating that apoptosis was an important mechanism by which dioscin inhibited cancer. Western blotting was employed to detect the expression of caspase-3, Bcl-2 and Bax in LNCaP cells. The expression of cleaved caspase-3 was significantly increased, and meanwhile procaspase-3 was markedly decreased. The expression of anti-apoptotic protein Bcl-2 was down-regulated, whereas the pro-apoptotic protein Bax was up-regulated. Moreover, the Bcl-2/Bax ratio was drastically decreased. These results suggested that dioscin possessed potential anti-tumor activity in human LNCaP cells through the apoptosis pathway, which might be associated with caspase-3 and Bcl-2 protein family.

Preparation of magnetic molecularly imprinted polymers for selective isolation and determination of kaempferol and protoapigenone in Macrothelypteris torresiana.

Novel uniform-sized magnetic molecularly imprinted polymers (MMIPs) were synthesized for selective recognition of active antitumor ingredients of kaempferol (KMF) and protoapigenone (PA) in Macrothelypteris torresiana (M. torresiana) by surface molecular imprinting technique in this study. Super paramagnetic core-shell nanoparticles (γ-MPS-SiO2@Fe3O4) were used as seeds, KMF as template molecule, acrylamide (AM) as functional monomer, and N, N'-methylene bisacrylamide (BisAM) as cross-linker. The prepared MMIPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), transmission electron microscopy (TEM) and thermo-gravimetric analysis (TGA), respectively. The recognition capacity of MMIPs was 2.436 times of non-imprinted polymers. The adsorption results based on kinetics and isotherm analysis were in accordance with the pseudo-second-order model (R (2)=0.9980) and the Langmuir adsorption model (R (2)=0.9944). The value of E (6.742 kJ/mol) calculated from the Dubinin-Radushkevich isotherm model suggested that the physical adsorption via hydrogen-bonding might be predominant. The Scatchard plot showed a single line (R (2)=0.9172) and demonstrated the homogeneous recognition sites on MMIPs for KMF. The magnetic solid phase extraction (MSPE) based on MMIPs as sorbent was established for fast and selective enrichment of KMF and its structural analogue PA from the crude extract of M. torresiana and then KMF and PA were detected by HPLC-UV. The established method showed good performance and satisfactory results for real sample analysis. It also showed the feasibility of MMIPs for selective recognition of active structural analogues from complex herbal extracts.

Determination of fifteen illegal colorants in traditional Chinese medicines by two hydrophobic DES-based microextraction methods coupled with an HPLC-DAD.

The dyeing and adulteration of traditional Chinese medicines (TCMs) are continuously updated. Valuable analytical methods for the daily inspection of illegal colorant additives in TCMs and the preparations are in demand. Two deep eutectic solvent (DES)-based vortex-assisted liquid-liquid microextraction (VA-LLME) and ultrasonic-assisted solid-liquid microextraction (UA-SLME) were developed for the sample pretreatment of ten water-soluble colorants and five water-insoluble colorants, respectively, followed by an HPLC-DAD detection. Fifteen colorants were analyzed at four detection wavelengths within 40 min of gradient elution. The optimal DES of VA-LLME and UA-SLME were screened from 23 homemade DESs. The factors affecting the extraction efficiency of VA-LLME and UA-SLME were optimized systematically. Under the optimal conditions, ten water-soluble colorants analyzed by DES-based VA-LLME-HPLC-DAD showed good linearity (R ≥ 0.9995) within the optimal linear range. The LODs and LOQs were 0.2-1.0 µg g-1 and 0. 5-5.0 µg g-1, respectively. The recoveries of spiked samples were 80.2%-104.7 %, with RSDs ≤ 4.39 %. Five water-insoluble colorants of Sudan I‒IV and Sudan 7B analyzed by DES-based UA-SLME-HPLC-DAD showed good linearity (R ≥ 0.9995) within the optimal linear range. The LODs and LOQs were 0.8-8.0 µg g-1 and 4.0-40.0 µg g-1, respectively. The recoveries of spiked samples were 94.2%-103.1 %, with RSDs ≤ 4.81 %. The proposed DES-based VA-LLME-HPLC-DAD was successfully applied to analyze six water-soluble yellow colorants in Cuscutae Semen, salted Cuscutae Semen, and four water-soluble red colorants in Schisandrae Chinensis Fructus. The proposed DES-based UA-SLME-HPLC-DAD was successfully applied to analyze five water-insoluble red colorants in Dieda pills. The study provides analytical method options for routine tests of water-soluble, water-insoluble, or both water-soluble/-insoluble illegal colorant additives in herbal medical materials and preparations by the relevant proposed DES-based sample pretreatment method or a combination of the two proposed DES-based methods.

Direct extraction of ten estrogens from milk samples with DVB/NVP-modified magnetic solid-phase extraction adsorbent followed by pre-column derivatization-UHPLC-MS/MS.

Estrogens and their analogues can cause harm to human health through the food chain. Ten estrogens in different milk samples were directly extracted by amphiphilic divinylbenzene/N-vinyl-2-pyrrolidone (DVB/NVP)-Fe3O4@SiO2-based magnetic solid-phase extraction (MSPE) followed by pre-column derivatization and ultra-high performance liquid chromatography tandem mass-spectrometry (UHPLC-MS/MS) detection. Under the optimal conditions, the limits of detection for ten analytes were in the range of 0.05-0.38 ng mL-1 in whole liquid milk matrix and 0.04-3.00 ng g-1 in milk powder matrix. The intra-/inter-day accuracy ranged in 83.4-113.8%, with RSDs in 2.5-15.0%. A total of 15 brands of liquid milk and milk powder samples were analyzed, and only estradiol was detected in three brands of boxed liquid milk within safe range. The proposed sample pretreatment eliminated the common protein precipitation process, improved the sample throughput, and has the potential for routine testing of estrogens and their analogues in market-sale milk samples.

(2S)-5, 2', 5'-trihydroxy-7-methoxyflavanone, a natural product from Abacopteris penangiana, presents neuroprotective effects in vitro and in vivo.

The aim of this study was to investigate the neuroprotective effects of (2S)-5, 2', 5'-trihydroxy-7-methoxyflavanone (TMF), a natural product from Abacopteris penangiana (Hook.) Ching, in oxidative stress-induced neurodegeneration models in vitro and in vivo. In PC12 cells, preincubation of TMF (3-20 µM) for 24 h decreased the dopamine-induced toxicity and attenuated the redox imbalance in PC12 cells through regulating the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG), which is a sensitive marker of oxidative stress. Additionally, long-term intraperitoneal (i.p.) injection of TMF (4 or 8 mg/kg/day) for 2 weeks significantly improved the behavioral performance of D-galactose (D-gal) treated mice in a Morris water maze test. Biochemical analysis revealed that TMF inhibited the activation of AP-1 (activator protein-1) and upregulated the level of BDNF (brain derived neurophic factor) as well as the ratio of GSH/GSSG in the hippocampus of D-gal treated mice. Furthermore, western blotting analysis indicated that TMF increased phosphorylation of cAMP-response element-binding protein (CREB). Therefore, the natural product TMF possessed a potential for the treatment of neurodegenerative diseases.

Identification of endogenous carbonyl steroids in human serum by chemical derivatization, hydrogen/deuterium exchange mass spectrometry and the quantitative structure-retention relationship.

Steroids are tetracyclic aliphatic compounds, and most of them contain carbonyl groups. The disordered homeostasis of steroids is closely related to the occurrence and progression of various diseases. Due to high structural similarity, low concentrations in vivo, poor ionization efficiency, and interference from endogenous substances, it is very challenging to comprehensively and unambiguously identify endogenous steroids in biological matrix. Herein, an integrated strategy was developed for the characterization of endogenous steroids in serum based on chemical derivatization, ultra-performance liquid chromatography quadrupole Exactive mass spectrometry (UPLC-Q-Exactive-MS/MS), hydrogen/deuterium (H/D) exchange, and a quantitative structure-retention relationship (QSRR) model. To enhance the mass spectrometry (MS) response of carbonyl steroids, the ketonic carbonyl group was derivatized by Girard T (GT). Firstly, the fragmentation rules of derivatized carbonyl steroid standards by GT were summarized. Then, carbonyl steroids in serum were derivatized by GT and identified based on the fragmentation rules or by comparing retention time and MS/MS spectra with those of standards. H/D exchange MS was utilized to distinguish derivatized steroid isomers for the first time. Finally, a QSRR model was constructed to predict the retention time of the unknown steroid derivatives. With this strategy, 93 carbonyl steroids were identified from human serum, and 30 of them were determined to be dicarbonyl steroids by the charge number of characteristic ions and the number of exchangeable hrdrogen or comparing with standards. The QSRR model built by the machine learning algorithms has an excellent regression correlation, thus the accurate structures of 14 carbonyl steroids were determined, among which three steroids were reported for the first time in human serum. This study provides a new analytical method for the comprehensive and reliable identification of carbonyl steroids in biological matrix.

Characterisation of phenols and antioxidant and hypolipidaemic activities of Lethariella cladonioides.

BACKGROUND: This study aimed to investigate the antioxidant and hypolipidaemic activities of an ethanol extract of Lethariella cladonioides (Nyl.) Krog (EE) and to characterise its chemical constituents. RESULTS: Nine phenols were identified as canarione, thamnolic acid, squamatic acid, vermicularin, norstictic acid, baeomycesis acid, lecanoric acid, barbatinic acid and usnic acid from analysis of EE by using high-performance liquid chromatography with a diode array detector-mass spectrometry. In antioxidant analysis in vitro, the highest scavenging rate of EEs on the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, superoxide anion, hydroxyl radicals and hydrogen peroxide was 81.55 ± 1.95%, 81.84 ± 4.00%, 74.28 ± 3.71% and 74.28 ± 3.71%, respectively. Meanwhile, after administration of EE for 6 weeks in high fat/cholesterol diet mice, the most significant reduction in levels of serum triglyceride, serum total cholesterol, serum low density lipoprotein cholesterol and liver malondialdehyde were 24%, 20%, 15% and 35%, respectively. The most significant increase in levels of serum high density lipoprotein cholesterol and liver superoxide dismutase was 35% and 88%, respectively. CONCLUSION: L. cladonioides possesses strong antioxidant and hypolipidaemic activities.

Nephroprotective activity of Macrothelypteris oligophlebia rhizomes ethanol extract.

CONTEXT: Macrothelypteris oligophlebia (Bak.) Ching (Thelypteridaceae) is a Chinese herbal medicine used traditionally for the treatment of diseases such as edema, boils, burns, and roundworms. However, research about the nephroprotective potential of this plant is not available. OBJECTIVE: Present study was designed to evaluate the protective effect of ethanol extract of M. oligophlebia rhizomes (EMO) on gentamicin (GM)-induced nephrotoxicity. MATERIALS AND METHODS: Rats were intraperitoneal (i.p.) injected with GM (100 mg/kg) to induce nephrotoxicity and simultaneously EMO (250 and 500 mg/kg) was orally given to GM-treated rats for 8 days. Blood urea nitrogen (BUN), serum creatinine (Cr), malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were evaluated in renal tissues. Histopathological analysis was used for evaluation of the renal damage. RESULTS: Administration with GM-induced renal dysfunction in rats. Pre-treatment with EMO (500 mg/kg) significantly decreased the levels of BUN, Cr, MDA and NO (decreased BUN from 12.71 ± 1.28 to 7.19 ± 0.23 mmol/l, Cr from 39.77 ± 5.34 to 19.17 ± 0.90 µmol/l, MDA from 5.60 ± 0.37 to 2.63 ± 0.24 nmol/ml, and NO from 868.17 ± 22.67 to 589.51 ± 8.83 µmol/ml), and also restored the activities of renal antioxidant enzymes (SOD, CAT, and GSH-Px) (restored SOD from 1.59 ± 0.17 to 2.94 ± 0.13 U/mg protein, CAT from 3.22 ± 0.34 to 10.57 ± 0.27 U/mg protein, and GSH-Px from 9.11 ± 1.29 to 20.72 ± 1.83 U/mg protein). DISCUSSION AND CONCLUSION: Our results suggest that the rhizomes of M. oligophlebia potentially have a protective role in renal tissue against oxidative stress in acute renal failure.

A novel, broad-spectrum antitumor compound containing the 1-hydroxycyclohexa-2,5-dien-4-one group: the disclosure of a new antitumor pharmacophore in protoapigenone 1.

The synthesis of a new compound 9 containing the 4-hydroxy-2,5-cyclohexadien-1-one system, a key elements toward elucidation of the protoapigenone 1 antitumor pharmacophore, was described. The compound showed potent in vitro antitumor potency with low micromolar IC(50)'s against breast, ovarian, prostate, liver, pancreas, and blood cancer cell lines tested and could inhibit tumor growth in vivo but no significant impairment of hematopoiesis or immune function was observed. The minimum structural pharmacophore of 1 has now been refined.

Neuropective constituents from the rhizomes of Abacopteris penangiana.

Two neuropective compounds were isolated from the rhizomes of Abacopteris penangiana, one was a new flavone and the other was a flavanone. Both compounds were firstly separated from natural plant. The isolation work was guided by the antioxidant activity. Both the compounds showed a significant antioxidant activity in vitro and a protective effect on dopamine-induced neurotoxicity in PC12 cells.

Dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of clozapine and chlorpromazine in urine.

A simple method has been proposed for the determination of clozapine (CLZ) and chlorpromazine (CPZ) in human urine by dispersive liquid-liquid microextraction (DLLME) in combination with high-performance liquid chromatography-ultraviolet detector (HPLC-UV). All important variables influencing the extraction efficiency, such as pH, types of the extraction solvent and the disperser solvent and their volume, ionic strength and centrifugation time were investigated and optimized. Under the optimal conditions, the limit of detection (LODs) and quantification (LOQs) of the method were 13 and 39 ng/mL for CLZ, and 2 and 6 ng/mL for CPZ, respectively. The relative standard deviations (RSDs) of the targets were less than 5.1% (C=0.100 µg/mL, n=9). Good linear behaviors over the tested concentration ranges were obtained with the values of R (2)>0.999 for the targets. The absolute extraction efficiencies of CLZ and CPZ from the spiked blank urine samples were 98.3% and 97.8%, respectively. The applicability of the technique was validated by analyzing urine samples and the mean recoveries for spiked urine samples ranged from 93.3% to 105.0%. The method was successfully applied for the determination of CLZ and CPZ in real human urine.

[Flavonoids with special B-ring from Macrothelypteris viridifrons and their anti-proliferative effects on tumor cell].

OBJECTIVE: To study the chemical constituents of Macrothelypteris viridifrons and their anti-proliferative effects on tumor cell. METHOD: The compounds were isolated by column chromatography with silica gel, C18 reverse-phase silica gel, sephadex LH-20, and their structures were elucidated on the basis of physiochemical propertities and spectral analysis. The antitumor activities of all compounds were tested with MOLT4, Hep G2, A-549, MCF-7, HT-29, PC-3 tumor cell lines. RESULT: Five compounds were isolated and identified as protoapigenone (1), protoapigenin (2), protoapigenin-4'-O-beta-D-glucopyanoside (3), 5,7-dihydroxy-2-(1,2-isopropyldioxy-4-oxo-cyclohex-5-enyl) -chromen-4-one (4), 5,7-dihydroxy-2-(1-hydroxy-2,6-dimethoxy-cyclohex-4-oxo) -chromen-4-one (5), respectively. CONCLUSION: All compounds were obtained from this plant for the first time. Compounds 1, 4 and 5 showed strong anti-proliferative effects on six tumor cells, which were in concentration-dependent manner.

Preparation of bovine serum albumin restricted access octadecyl/phenyl-mixed-functionalized magnetic silica nanoparticles for magnetic solid phase extraction of antidepressants in aquatic products followed by UHPLC-MS/MS.

Pharmaceuticals are widespread in aquatic ecosystem, which may pose a potential threat to fish and human. In the study, a robust and reliable magnetic solid-phase extraction (MSPE) based on bovine serum albumin (BSA) restricted access octadecyl/phenyl-mixed-functionalized magnetic silica nanoparticles (BSA-C18/Ph-Fe3O4@SiO2 NPs) as sorbent was developed for the extraction of venlafaxine, paroxetine, fluoxetine, norfluoxetine, sertraline and diphenhydramine from the muscle extracts of aquatic products followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection. The homemade sorbent showed appropriate compatibility in aqueous solution and good performance in reducing matrix interference of snakehead muscle tissue extracts with absolute matrix effect ranging in 95.4%-105.5%. The protocol was validated in analyte-free snakehead muscle with favorable recoveries ranging in 91.6%-103.6% and relative standard deviations (RSDs) less than 9.5%. Limits of detection (LODs) of the drugs were lower than 0.018 µg kg-1. Short-term drug-exposure experiments at low and high doses were conducted on snakeheads, and the measured contents of analytes were in the range 0.029-9.58 µg kg-1 with appropriate recoveries (90.0%-114.0%). The approach was extensively applied for the analysis of twelve species of market-sale aquatic products (total 37 samples), and up to 1.868 and 0.521 µg kg-1 of diphenhydramine and venlafaxine were measured, respectively. The approach shows remarkable potential in biological complex samples.

Parathelypteriside attenuates cognition deficits in d-galactose treated mice by increasing antioxidant capacity and improving long-term potentiation.

Parathelypteriside (PG), a stilbenoid compound, was extracted from Parathelypteris glanduligera (kze.) ching that exhibits antioxidative and anti-inflammatory effects. The aim of this study was to investigate the protective effect of PG against the d-galactose (d-gal)-induced neurotoxicity in mice. It was found that long-term intraperitoneal (i.p.) injection of PG (5 or 10 mg/(kg day)) for two weeks significantly improved the behavioral performance of d-gal-treated mice in both Morris water maze test and step-down avoidance test. Biochemical examination revealed that PG reduced the increased levels of malondialdehyde (MDA), and attenuated the decreased activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase in the hippocampus of d-gal-treated mice. Furthermore, the electrophysiological assay showed that PG significantly rescued the long-term potentiation (LTP) impairment in mice hippocampus, and western blotting analysis indicated that the effects of PG on LTP might be attributed to the activation of cAMP-response element-binding protein (CREB). Together, these results suggested that the natural product PG represented a potential source of medicine for the treatment of the neurodegenerative diseases.

Magnetic solid-phase extraction coupled with UHPLC-MS/MS for four antidepressants and one metabolite in clinical plasma and urine samples.

Aim: Routine therapeutic drug monitoring is highly recommended since common antidepressant combinations increase the risk of drug-drug interactions or overlapping toxicity. Materials & methods: A magnetic solid-phase extraction by using C18-functionalized magnetic silica nanoparticles (C18-Fe3O4@SiO2 NPs) as sorbent was proposed for rapid extraction of venlafaxine, paroxetine, fluoxetine, norfluoxetine and sertraline from clinical plasma and urine samples followed by ultra-HPLC-MS/MS assay. Results: The synthesized C18-Fe3O4@SiO2 NPs showed high magnetization and efficient extraction for the analytes. After cleanup by magnetic solid-phase extraction, no matrix effects were found in plasma and urine matrices. The analytes showed LODs among 0.15-0.75 ng ml-1, appropriate linearity (R ≥ 0.9990) from 2.5 to 1000 ng ml-1, acceptable accuracies 89.1-110.9% with precisions ≤11.0%. The protocol was successfully applied for the analysis of patients' plasma and urine samples. Conclusion: It shows high potential in routine therapeutic drug monitoring of clinical biological samples.

Magnetic solid-phase extraction modified Quick, Easy, Cheap, Effective, Rugged and Safe method combined with pre-column derivatization and ultra-high performance liquid chromatography-tandem mass spectrometry for determination of estrogens and estrogen mimics in pork and chicken samples.

In this study, conventional Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method was modified by magnetic solid-phase extraction (MSPE) for purification/pre-concentration of eleven estrogens and estrogen mimics from the extracts of pork and chicken muscles, prior to dansyl chloride (DNS-Cl) derivatization coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay. Dual octadecyl- and 2-aminoethyl-3-aminopropyl- groups functionalized mesoporous silica core-shell magnetic nanoparticles (C18/NH2-Fe3O4@mSiO2 MNPs) were synthesized and employed as MSPE sorbent with remarkable aqueous compatibility in comparison with conventional C18 functionalized sorbent. The proposed MSPE is easier to handle than the traditional SPE purification process in QuEChERS method. The lab-prepared MNPs were characterized by transmission electron microscope (TEM), brunner-emmet-teller (BET), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA) and vibrating sample magnetometer (VSM). Pre-column derivatization was conducted to significantly enhance the sensitivity of the analytes in MS/MS via analyzing their derivatives in positive ion mode instead of analyzing their original forms in negative ion mode. Under the optimal sample pretreatment and instrumental analysis conditions, the approach showed low limits of detection (LODs, 0.02‒3.00 µg kg-1), appropriate recoveries (81.1‒115.4%) and acceptable precisions (0.48‒15.1%, n = 6), with good feasibility and future prospect of trace compounds analysis in complex food samples.

Novel PEP-PAN@PSF rods extraction of EDCs in environmental water, sediment, and fish homogenate followed by pre-column derivatization and UHPLC-MS/MS detection.

In the study, novel polysulfone hollow fiber membrane (PSF) supported polar enhanced phase (PEP) particles-polyacrylonitrile (PAN) polymer thin-film rods (PEP-PAN@PSF rods) were developed for the extraction of five steroidal endocrine disrupting chemicals (EDCs) (estrone (E1), estradiol (E2), estriol (E3), ethinyloestradiol (EE2), 2-methoxyestradiol (2ME2)) and four phenolic EDCs (bisphenol A (BPA), hexestrol (HEX), diethylstilbestrol (DES), dienestrol (DE)) in environmental water, sediment, and fish muscle homogenates, followed by pre-column derivatization and ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The traditional preparation method for thin-film rods was improved by introducing a supporting membrane PSF between the external thin-film coating and the internal bare rod, avoiding the conventional pre-corrosion by strong acid/base. The commercial PEP prepared rods showed competitive capacity for both polar and nonpolar EDCs. In addition, pre-column derivatization with dansyl chloride (DNS-Cl) was adopted for the phenolic analytes prior to UHPLC-MS/MS detection, leading to a significant enhancement of sensitivity via analyzing the dansylated derivatives under positive electrospray ionization (ESI) mode instead of the analytes under negative ESI mode. The protocol was validated in four matrices including environmental water, sediment and two fish species. No matrix effects were observed in four matrices. The limits of detection (LODs) for the analytes were in the range of 0.002-0.072 µg L-1 for environmental water, 0.032-0.734 ng g-1 for sediment, and 0.011-0.435 ng g-1 for two fish species, respectively. Appropriate linearity was observed for all the analytes with correlation coefficients (R2) above 0.997. The intra-day trueness of the approach at low, medium and high levels was in the range of 86.6-116.1% with relative standard deviations (RSDs) lower than 15.4%. And the inter-day trueness was in the range of 84.6-114.8% with RSDs lower than 16.3%. The proposed method was successfully applied for the analysis of nine EDCs in environmental water, sediment, and fish muscle homogenates.

Extraction and determination of some psychotropic drugs in urine samples using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

A simple, rapid and sensitive method termed as dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography-ultraviolet detector (HPLC-UV) has been proposed for the determination of three psychotropic drugs (amitryptiline, clomipramine and thioridazine) in urine samples. The determination was performed on a C(8) column under the optimal chromatographic conditions (mobile phase: ammonium acetate (0.03 mol L(-1), pH 5.5)-acetonitrile (60:40, v/v); flow rate: 1.0 mL min(-1); detection wavelength: 238 nm). Several factors influencing the extraction efficiency of the target drugs, such as pH, extraction and disperser solvent type and their volume, extraction time and ion strength were studied and optimized. Under the optimal DLLME conditions, the absolute recoveries of amitryptiline, clomipramine and thioridazine from the urine samples were 96, 97 and 101%, respectively. The detection limits (LODs) and quantification (LOQs) of the proposed approach were 3 and 10 ng mL(-1) for amitryptiline, 7 and 21 ng mL(-1) for clomipramine, and 8 and 25 ng mL(-1) for thioridazine, respectively. The relative standard deviations (RSDs) for nine replicate determinations at 0.100 microg mL(-1) level of target drugs were less than 4.8%. Good linear behaviors over the investigated concentration ranges were obtained with the values of R(2)>0.998 for the target drugs. The proposed method was successfully applied to the real urine samples from two female patients under amitryptiline and clomipramine treatment, respectively.

Online YPA4 resin microcolumn separation/preconcentration coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) for the speciation analysis of mercury in seafood.

A simple and effective method for the determination of trace amounts of methylmercury (MeHg(+)) and inorganic mercury (Hg(2+)) in seafood was developed by online microcolumn separation/preconcentration combined with inductively coupled plasma optical emission spectrometry (ICP-OES). It was found that Hg(2+) could be quantitatively adsorbed by YPA 4 resin from pH 7.0 to strong acidic medium (6 mol L(-1) HCl) and that MeHg(+) was retained by the YPA 4 microcolumn only at pH 1.0-7.0. Therefore, a strong acidic medium (about 5 mol L(-1) HCl), which could liberate mercury species from biological samples, was used to directly separate inorganic Hg(2+) from total Hg, and MeHg(+) in effluent was retained by YPA 4 column after the effluent was adjusted to pH 1.5. The effects of acidity, sample flow rate and volume, elution solution, and interfering ions on recovery of the two mercury species have been systematically investigated. Under optimal conditions, the limits of detection (LODs) were 72 and 44 ng L(-1) for Hg(2+) and MeHg(+) (as Hg) with online concentration factors of 12.5 and 12.1, respectively. The relative standard deviations (RSDs) for nine replicate determinations at 5 ng mL(-1) levels of mercury species were 2.7 and 2.0% for Hg(2+) and MeHg(+), respectively. The calibration graphs were linear with a correlation coefficient of 0.9902 in the range of 0.5-100 ng mL(-1) for Hg(2+) and 0.9976 in the range of 0.1-100 ng mL(-1) for MeHg(+), respectively. The developed method was successfully applied to the direct determination of MeHg(+) and Hg(2+) in seafood samples, and the recoveries for the spiked samples were in the range of 89.9-102.4% (MeHg(+)) and 87.0-104.6% (Hg(2+)), respectively. The method was validated by analyzing a certified reference material DORM-2 (dogfish muscle), and the determined values were in good agreement with certified values.

Identification and characterization of curcuminoids in turmeric using ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry.

A three-step strategy was developed for systematic characterization of curcuminoids in turmeric. Based on UHPLC-QTOF-MS/MS analysis, 89 curcuminoids including 16 novel ones were identified in the turmeric samples using this approach. During the identification process, false positive results were excluded by combining the positive and negative ESI-MS/MS analyses. Moreover, the characterization of the keto and enol forms of type A, B and C curcuminoids was first discussed and they were clearly distinguished using negative ESI-MS/MS method with UV spectra analyses. The structures of detected curcuminoids were identified and rationalized in both ion modes. Additionally, the fragmentation behaviors of the 15 types of curcuminoids were clearly illustrated in this work, which will be helpful for detection and identification of corresponding trace curcuminoids in complex turmeric samples using UHPLC-QTOF-MS/MS methods.