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Objective: To evaluate the effect of low molecular weight chitosan (LMW-CTS) and its nanoparticles (LMW-CTS-NPs) on the intestinal permeability of Panax notoginseng saponins (PNS) by using Caco-2 cell model. Methods: LMW-CTS was prepared by combining chitosanase hydrolysis combined with ultrafiltration separation technology, and molecular weight of LMW-CTS was determined by using permeation gel chromatography (GPC). LMW-CTS-NPs were prepared by ionic gel method, and characterized by scanning electron microscopy, nano particle sizer, and flourier transformation infrared spectroscopy. Caco-2 cell model was established and validated to evaluate the effects of LMW-CTS and LMW-CTS-NPs on the intestinal permeability of PNS. Results: LMW-CTS has a molecular weight of 5 760 and a polydispersity coefficient of 1.42. LMW-CTS-NPs have a round shape and narrow particle size distribution, with an average particle size of 115.5 nm and zeta potential of +37.1 mV. The apparent permeability coefficients (Papp, AB→BL) of PNS was less than 1 × 10-6 cm/s, indicating a poor permeability. In LMW-CTS group, the Papp of R1 and Rg1 was increased by 17.83% and 20.29%, respectively, but no significant effect of promotion was observed on other components. However, the Papp of R1, Rg1, Re, Rb1, and Rd in LMW-CTS-NPs group was increased by 35.66%, 23.28%, 29.41%, 37.99%, and 36.00%, respectively, compared tothe control group. Conclusion: LMW-CTS can significantly promote the intestinal mucosal permeability of R1 and Rg1 in PNS, but has no significant effect on Re, Rb1, and Rd. LMW-CTS-NPs significantly increased the permeability of the major monomer saponin components in PNS. Namely, the intestinal permeability of PNS can be further improved by transforming LMW-CTS into LMW-CTS-NPs.
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italic>K-values of 56 batches of 7 types of povidone were measured by microfluidic rheometry and with a Ubbelohde capillary viscometer. The K-values of the two methods were tested by SPSS software and the results showed that there was no significant difference between the two methods (P > 0.05). Taking K-values measured with the Ubbelohde capillary viscometer (Ku) as the abscissa and K-values measured by microfluidic rheometry (Km) as the ordinate a linear equation was calculated: Km = 0.893 9Ku + 4.617 6, R2 = 0.986 2, with good linearity, indicating that the microfluidic rheometer method can replace the Ubbelohde capillary viscometer in determining K-values of povidone. The microfluidic rheometer method has the benefits of less sample consumption, faster determination, and is more accurate, and it can be used with high-throughput automatic acquisition, which provides a more convenient method for the determination of K-values of different types of povidone. The weight-average molecular weights (Mw) of each type of povidone were measured by gel permeation chromatography-multi angle laser light scattering (GPC-MALLS), and the relationship between Mw and Km was lgMw = -0.000 4 Km2 + 0.072 7 Km + 2.791, R2 = 0.990 1. The fitting relationship was good, and Mw could be calculated by Km by the equation.
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Objective:To set up an automatic gel permeation chromatography-solid phase extraction purification-ultra performance liquid chromatography-tandem mass spectrometry ( GPC-SPE-UPLC-MS/MS ) method for the quantitative determination of 14 carba-mates pesticide residues in Chinese herbal pieces. Methods:The samples were extracted by acetonitrile, and kept in constant volume with ethyl acetate-cyclohexane (1: 1, v/v). The extract was purified by GPC combined with amino solid phase extraction column (Carb/NH2). After UPLC gradient elution separation on an Agilent Poroshell 120EC-C18 column using acetonitrile-0. 1% formic acid as the mobile phase,the target pesticides were determined by tandem mass spectrometry in a multi-reaction monitoring ( MRM) mode. Results:The 14 kinds of carbamates pesticides had good linear relationships within the range of determination (r>0. 9990), and the detection limit was 0. 02-0. 35μg·kg-1 . When the spiked levels were 1, 10 and 50μg·L-1 , the recoveries were 74. 2%-108. 8%, and the RSD was 1. 25%-6. 73%(n=6). Conclusion:The method simplifies the pretreatment operation and shortens the analysis time with good selectivity and high sensitivity, which can be used for the determination of carbamates pesticide residues in Chinese herbal pieces.
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Background & objectives: Several host defense proteins known to possess antimicrobial activities are present on mucosal surfaces and are consequently found in body fluids of vertebrates. Naturally occurring protease inhibitors like cystatins, especially cystatin C (cys C), are abundantly present in human seminal plasma. Although its antiviral activity against herpes simplex virus (HSV) has been demonstrated, the role of this protein against HIV is not well studied. Therefore, the aim of the present study was to evaluate the anti-HIV activities of cys C, which is present innately in the male reproductive tract. Methods: Protein-protein interaction of cys C with various HIV proteins was studied using a commercially available HIV blot and specific interaction with HIV protease was studied by dot-blot technique using commercially available cys C. to purify biologically active cys C from human seminal plasma to be used for subsequent experiments, gel-permeation chromatography followed by affinity chromatography was used. The HIV infectivity inhibition activity of the purified cystatin C was tested in TZM-bl cells. To study its activity on HIV protease, time-course enzyme kinetics studies were performed using spectrometric assay. Results: Cystatin C reacted with some HIV proteins including HIV protease. Biologically active cys C was purified using gel permeation chromatography followed by affinity chromatography. When tested in TZM-bl cells, purified cystatin C demonstrated HIV-infectivity inhibitory activity (IC50: 0.28 μM). enzyme kinetic studies demonstrated that it abrogated the action of HIV protease on its substrate. Interpretation & conclusions: The present data demonstrate that cystatin C possesses anti-HIV activities. molecular models need to be designed with this protein which would assist towards prevention/ therapeutics against HIV.
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A gel permeation chromatography ( GPC ) coupled with solid phase extraction and gas chromatography-mass spectrometric ( GPC-SPE-GC/MS ) method was developed to analyze seven kinds of organophosphate esters ( OPEs ) , including tri-n-butylphosphate, tri ( 2-chloroethyl ) phosphate, triphenyl phosphate, tris ( 2-butoxyethyl ) phosphate, tri-o-tolylphosphate, tri-m-tolylphosphate, and tri-p-tolylphosphate) in human serum. The recoveries of cleanup methods between GPC-silica/alumina column and H2 SO4-silica/sulfuric acid gel column were compared. The purification method with the GPC-silica/alumina column didn’t destroy the structure of organophosphate esters ( OPEs ) and could effectively remove some protein and lipid matrix influence in serum. The developed method was verified using the spiked blank and the spiked serum, the good recoveries and reproducibilities were achieved. The recoveries of all of OPEs in spiked blank (n=3) were all more than 75%. The recoveries of d12-TCEP and d15-TPhP in human serum samples (n=9) were 86. 3%±21. 6% and 103. 1%±16. 5%, respectively. In human serum samples (n=9), the detection ratios for TnBP, TCEP, TPhP, TBEP and m-TTP were more than 90% in all of the serum samples, p-TTP was only 30%, o-TTP was not detectable. The concentrations of TnBP, TCEP, TPhP, TBEP and m-TTP in serum were 3. 4-46. 5 ng/g lipid, 248. 6-958. 2 ng/g lipid, n. d. -4. 2 ng/g lipid, n. d. -49. 9 ng/g lipid and n. d.-23. 1 ng/g lipid, respectively.
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A method was developed for the determination of eight steroid hormones ( estrone, α/β-estradiol, estriol, testosterone, epitestosterone, progesterone and testosterone propionate ) in butter samples by gel permeation chromatography ( GPC) purification-followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were first extracted by ethylacetate/cyclohexane (1:1, V/V) and the extract was later degreased by GPC column. Then, the GPC concentrate was separated using a C18 column ( 100 mm í2. 0 mm i. d. , 3. 0 μm) with gradient elution of acetonitrile/water. Finally, the steroid hormone components were qualitatively and quantitatively determined by mass spectrometer with electrospray ionization in multi reaction monitoring mode. Using matrix matched external standard method, good linearity in response could be obtained in the concentration range of 1 . 0-20 . 0 μg/kg with correlation co-efficiency larger than 0 . 999 . The detection limits of the method were 0. 04-0. 30 μg/kg and the quantification limit was 1. 0 μg/kg. At the spike levels of 1. 0, 2. 0 and 4. 0μg/kg, the recoveries of hormones were within the range of 64. 1%-110%, and the relative standard deviation ( RSD) was less than 11%. The results show that the method is accurate and reliable, and meets the requirements for determination of 8 steroid hormones in butter samples.
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A stimulate method for determination of polybrominated diphenyl ethers ( PBDEs) and derivatives (OH-PBDEs and MeO-PBDEs), tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD) in egg samples was developed by gel permeation chromatography ( GPC) and dispersive solid phase extraction ( DSPE) combined with liquid chromatography tandem mass spectrometric ( HPLC-MS/MS) and gas chroma-tography-negative chemical ionization mass spectrometry ( GC-NCI/MS ) . The analytes were extracted with mixture of hexane and dichloromethane (1∶1, V/V) by accelerated solvent extraction (ASE), and purified by 100 mg C18 dispersive solid phase extraction ( SPE) sorbents followed with gel permeation chromatography (GPC) , and then analyzed by liquid chromatography tandem mass spectrometric (HPLC-MS/MS) and gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS), respectively. The quantita-tion was carried out external standard method. The recoveries of objects were 64. 5%-97. 2% and 65. 6%-109 . 2% ( except BDE85 was 54 . 8%, OH-BDE-137 was 47 . 4%) spiked at 1 . 0 μg/kg or 5 . 0 μg/kg in egg white and egg yolk, respectively. The relative standard deviations (RSDs) were less than 20. 2%. The limits of quantitation (LOQ) for the object were 0. 01-0. 2 μg/kg.
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A method for the simultaneous determination of 34 pesticides in sunflower oil, soybean oil and corn oil was developed. The samples were extracted and purified by a modified QuEChERS method, and then the supernatant was analyzed by on-line gel permeation chromatography-gas chromatography-mass spectrometry ( GPC-GC-MS ) . The linear range was from 0 . 01 to 0 . 2 mg/L with a good correlation coefficients ( r≥0. 9913). The average recoveries of 31 pesticides (except p,p′-DDE, p,p′-DDD, p,p′-DDT. For detail, please reference to section 3 . 6 ) ranged from 70 . 3% to 115 . 4%, 69 . 5% to 112 . 6% and 70 . 2% to 116 . 1%spiked at 0. 05 μg/g and 0. 1 μg/g with the relative standard deviations (RSDs, n=6) less than 13. 3%, 13. 5% and 12. 1% in sunflower oil, soybean oil and corn oil samples, respectively. The LODs of this method ranged from 0. 0692 to 2. 28, 0. 0559 to 2. 01 and 0. 0584 to 2. 14μg/kg (S/N=3) in sunflower oil, soybean oil and corn oil samples respectively. The convenient operation and versatility of this method are suitable for the fast screening and detection of 34 pesticide residues in sunflower oil, soybean oil and corn oil.
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OBJECTIVE: To establish a gas chromatography-mass spectrometry (GC-MS) method for detecting 192 pesticides in flos lonicerae. Several bathes of flos lonicerae have been determined in order to find out the current status of pesticide residues in flos lonicerae. METHODS: The samples were extracted with acetone, and cleaned-up by the combination of gel permeation chromatography (GPC) and solid-phase extraction (SPE), and determined by GC-MS. RESULTS: The recoveries of most pesticides ranged from 70% to 110% with relative standard deviations (RSDs) ≤15%. The limits of determination were below 0.01 mg·kg-1. CONCLUSION: This method is sensitive, accurate, and can be used for the determination of multi-residual pesticides in flos lonicerae. Copyright 2012 by the Chinese Pharmaceutical Association.
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Objective: To develop a high performance gel permeation chromatography (HPGPC) method for quality control of Tremella fuciformis polysaccharide. Methods: The separations were carried out with two series-wound columns including Shodex Sugar KS-804 (300 mm x 8 mm, 7 μm) and KS-805 (300 mm x 8 mm, 17 μm), water as mobile phase at flow rate 0.8 mL/min, column temperature at 40°C, injection volume 40 μL, and differential index detector. Results: T. fuciformis polysaccharide peak was located within 14.40-15.30 min and corresponding molecular weight was 1.26 × 106-1.39 × 106. The linearity was good during 0.01-2.0 mg/mL (r = 0.999). The polysaccharide concentration was 1.1-1.5 mg/mL and 0.8-1.1 mg/mL with precipitation of T. fuciformis polysaccharide and blue dextran as reference, respectively. LOD and LOQ were 0.8 and 2 μg, respectively. Conclusion: The method is simple, quick, and accurate, and has good repeatability and high sensitivity, which is fitful for quality control.
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Crude ethanolic extracts from Blepharocalyx salicifolius (Kunth) O. Berg, Myrtaceae, was fractioned by Gel Permeation Chromatography, using SephadexTM LH-20 gel. Sixteen fractions were obtained and were supplied to cytotoxicity in vitro assay against Leishmania (L.) amazonensis amastigota cells. It was observed eight cytotoxic fractions against Leishmania (L.) amazonensis amastigota cells at range of 19 to 29 µg.mL-1. Two of them were not citotoxic against human peripheral blood mononuclear cell, with a great potential to isolation of more selective leishmanicidal substances.
O extrato etanólico bruto de Blepharocalyx salicifolius (Kunth) O. Berg, Myrtaceae, foi fracionado por meio de Cromatografia de Permeação em Gel, utilizando-se SephadexTM LH-20. Dezesseis frações foram obtidas e foram submetidas ao ensaio de citotoxicidade in vitro contra células amastigotas de Leishmania (Leishmania) amazonensis. Verificou-se atividade citocida contra células amastigotas de Leishmania (L.) amazonensis em oito frações, a uma concentração de 19 a 29 µg.mL-1. Duas destas frações apresentaram baixa toxicidade para células mononucleares de sangue periférico humano, com grande potencial de isolamento de substâncias leishmanicidas mais seletivas.
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Se validó e implementó un método multirresiduo para la determinación de cinco plaguicidas N-metilcarbamatos (N-MC) y cuatro metabolitos de estos en fresa. La extracción se realizó con acetato de etilo. La limpieza se llevó a cabo por cromatografía de permeación en geles (CPG) utilizando como fase estacionaria un polímero de estireno divinilbenceno a 3 % de entrecruzamiento empacado en una columna de vidrio de 20 cm x 10 mm D.I. y un solvente de elución compuesto por acetato de etilo ciclohexano (1:1) a un flujo de 1 mL/min. Se encontró que al eliminar los primeros 7 mL se eliminaban los interferentes de la matriz, y que en la fracción de 7 a 22 mL se encontraban los N-metilcarbamatos y sus metabolitos. La determinación final se realizó por HPLC con derivatización pos-columna y detección por fluorescencia usando una columna C-18 de 25 cm x 4.6 mm D.I, 5 [1]m, y un gradiente de elución compuesto de acetonitrilo, metanol y agua. Con la limpieza llevada a cabo se mostró que el método es específico, selectivo, lineal en un rango de concentraciones desde 0,12 hasta 2,31 mg/kg, suficientemente sensible con límites de detección y cuantificación entre 0,011 - 0,021 mg/kg y 0,021 - 0,075 mg/kg, respectivamente, preciso y exacto con recuperaciones entre el 80 y el 110%. El método validado se utilizó para determinar residuos de N-MC y sus metabolitos en muestras de fresa de tres municipios del departamento de Cundinamarca, y un municipio del departamento del Cauca, Colombia. Se encontraron residuos en una muestra del departamento del Cauca.
A multiresidue method for analysis of five N-methylcarbamate pesticides (N-MCs) and four of their metabolites in strawberry was validated and implemented. Pesticide residues were extracted from strawberry samples with ethyl acetate and the extracts were cleaned by gel permeation chromatography (GPC) on 3% crosslinked styrene divinylbenzene polymer packed in a glass column of 20 cm x 10mmi.d. and ethyl acetate ciclohexane (1:1) as solvent elution at a flow rate of 1 mL/min before injection in the chromatograph. The first 7 mL were discarded to remove matrix interferents. The fraction between 7 and 22 mL where the N-methylcarbamate pesticides and their metabolites are present, was collected. Final determination was carried out by HPLC with post-column derivatization and fluorescence detection in a C-18 column of 25 cm x 4.6 mm i.d, 5 [1]m with a gradient of acetonitrile-methanol-water. The clean up procedure demonstrated that the method is specific, selective, linear over a concentration range from 0.11 to 2.31 mg/kg, sensible enough with limit of detection and quantification between from 0.011 to 0.021 mg/kg and from 0.021 to 0.075 mg/kg respectively, as well as precise and accurate with recoveries between 80 - 110%. The validated method was used to determine N-MCs residues and their metabolites in strawberry samples in three Cundinamarca counties and one Cauca county, Colombia. Residues were detected in one Cauca county sample.
Um método multi-resíduo para a determinação de cinco pesticidas derivados de N-metil carbamatos (N-MCs) e quatro de seus metabólitos em morangos foi validado e implementado. A extração dos resíduos de pesticidas foi realizada com acetato de etila e a limpeza foi realizada por cromatografia de permeação em gel (CPG) utilizando como fase estacionária um polímero de estireno divinilbenzeno com 3% de entrecruzamento, empacotado em uma coluna de vidro de 20 cm x 10 mm d.i., e solvente de eluição composto por acetato de etila : ciclohexano (1:1) em fluxo de 1 mL/min, antes da injeção no cromatógrafo. Os primeiros 7 mL foram descartados para eliminação de interferentes da matriz, nas frações de 7 a 22 mL estavam presentes os N-metil carbamatos e seus metabolitos. A determinação final foi realizada por HPLC com derivatização pós-coluna e detecção por fluorescência usando uma coluna C-18 de 25 c x 4,6 mm d.i., 5[1]m, e um gradiente de eluição composto por acetonitrila, metanol e água. Com a limpeza realizada foi possível mostrar que o método é específico, seletivo, linear no intervalo de concentrações de 0.12 a 2.31 mg/kg, suficientemente sensível com limites de detecção e quantificação entre 0.011 - 0.021 mg/kg e 0.021 - 0.075 mg/kg respectivamente, preciso e exato com recuperação entre 80 e 110%. O método validado foi utilizado para determinar residuos de N-MCs e seus metabólitos em amostrestado de Cauca, Colombia. Resíduos foram encontrados em uma amostra do estado de Cauca.
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Los benzimidazoles son fungicidas de acción sistémica muy utilizados en la protección de cultivos de frutas y hortalizas. En este trabajo se validó una metodología para la determinación de residuos de benomyl, carbendazim y tiabendazol, en fresa y lechuga por cromatografía líquida de alta eficiencia con detector de arreglo de diodos (HPLC-DAD). Los residuos de benomyl se determinaron luego de su conversión a carbendazim. La extracción de los residuos de las muestras se realizó con acetato de etilo y la limpieza se llevó a cabo por cromatografía de permeación en gel (GPC). La determinación analítica se realizó por HPLC-DAD en fase reversa. La metodología es selectiva, específica, precisa y exacta. Las curvas de calibración son lineales en un rango de concentración de 1,24 a 6,19 mg/kg con límites de detección de 0,27 y 0,40 mg/kg y límites de cuantificación de 0,85 y 1,35 mg/kg para carbendazim y tiabendazol respectivamente. Los porcentajes de recuperación son del orden del 90%. No se encontraron residuos de estos compuestos en muestras recolectadas en algunos municipios de Cundinamaraca, Colombia.
Systemic fungicides like benzimidazolic compounds are used to protect several crops of fruits and vegetables. In this work a new method for analysis of benomyl, carbendazim and thiabendazol in strawberry and lettuce by High-performance liquid chromatography with diode array detector (HPLC-DAD) was validated. Benomyl residues were determined after its conversion to carbendazim. Pesticide residues were extracted from strawberry and lettuce samples with ethyl acetate and these extracts were cleaned up by gel permeation chromatography (GPC). Final determination was carried out by HPLC-DAD in reverse phase column. The method is selective, specific, precise and accuracy. The calibrate curves show linearity over concentration range of 1,24 to 6,19 mg/kg, with detection limits of 0,27 and 0,40 mg/kg and quantification limits of 0,85 and 1,35 mg/kg for carbendazim and thiabendazol respectively. The recovery experiments yielding averages of 90%. No residues of these compounds were founded in recollected samples from specific states of Cundinamarca, Colombia.