1,664 results match your criteria pre-column derivatization

Fluorimetric Analysis of Five Amino Acids in Chocolate: Development and Validation.

Molecules 2021 Jul 16;26(14). Epub 2021 Jul 16.

Laboratory of Pharmaceutical Analysis, Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.

Amino acids present ergogenic action, helping to increase, protect, and restore the muscular system of young athletes. Moreover, the encapsulation of five relevant amino acids in chocolate pellet form will appeal to them, facilitating their daily consumption. A reliable HPLC fluorimetric method was developed to detect and quantitatively determine L-Leucine, L-Isoleucine, L-Histidine, L-Valine, and β-Alanine in chocolate using aniline as an internal standard. Read More

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Identification and direct determination of fatty acids profile in oleic acid by HPLC-CAD and MS-IT-TOF.

J Pharm Biomed Anal 2021 Jul 2;204:114238. Epub 2021 Jul 2.

Chemical Laboratory Second Laboratory, Jiangsu Institute for Drug and Food Control, Nanjing, China; NMPA Key Laboratory for Impurity Profile of Chemical Drugs, National Medical Products Administration, Beijing, China. Electronic address:

Oleic acid is a pharmaceutical excipient and has been widely used in many dosage forms. It remains unclear in terms of the fatty acids (FAs) profile. In this study, a sensitive and direct method based on high-performance liquid chromatography coupled with charged aerosol detector (HPLC-CAD) was developed to study the compositions of oleic acid. Read More

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Determination and analysis of monosaccharides in Polygonatum cyrtonema Hua polysaccharides from different areas by ultra-high-performance liquid chromatography quadrupole trap tandem mass spectrometry.

J Sep Sci 2021 Jul 16. Epub 2021 Jul 16.

School of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230012, P. R. China.

We wanted to explore a new method for the determination of monosaccharides in Polygonatum cyrtonema Hua polysaccharide using the ultra-high-performance liquid chromatography quadrupole trap tandem mass spectrometry. In this study, hydrochloric acid was used instead of trifluoroacetic acid to hydrolyze polysaccharides and hydrolysis time was greatly reduced from 5-9 h to 1 h. The 1-phenyl-3-methyl-5-pyrazolone was used for pre-column derivatization of monosaccharides. Read More

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[Quantitative analysis of tryptophan and its metabolites in urine by ultra performance liquid chromatography-tandem mass spectrometry].

Se Pu 2021 May;39(5):518-525

Jilin Ginseng Academy, Changchun University of Chinese Medicine, Changchun 130117, China.

Tryptophan (Trp), also known as α-amino -indolepropionic acid, is an essential amino acid, which is involved in various physiological processes. Studies have shown that tumors, infectious diseases, and neurological diseases are accompanied by Trp-related metabolic disorders. Understanding the excretion of Trp and its metabolites in normal individuals is of great significance for treating Trp-related diseases and monitoring the health. Read More

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[Determination of 18 amino acids in three different kinds of milk powder by ultra performance liquid chromatography coupled with pre-column derivatization].

Se Pu 2021 May;39(5):472-477

Technical Center for Animal Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China.

In recent years, goat milk powder and camel milk powder have gained popularity among consumers. Due to their potential low allergenicity, these milk powders have become a substitute for breast milk, especially for infants, and for people with lactose intolerance. In this paper, a method was developed for the simultaneous determination of 18 amino acids (AAs), histidine (His), serine (Ser), arginine (Arg), glycine (Gly), aspartic acid (Asp) combined with asparagine (Asn), glutamic (Glu), glutamine (Gln), threonine (Thr), alanine (Ala), proline (Pro), lysine (Lys), tyrosine (Tyr), methionine (Met), valine (Val), isoleucine (Iso), leucine (Leu), and dimer of cysteine (Cys) combined with cysteine (L-Cys-Cys), phenylalanine (Phe), taurine (Tau) in milk, goat milk, and camel milk power. Read More

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[Determination of tranexamic acid in essential cosmetics by pre-column derivatization capillary electrophoresis coupled with electrogenerated chemiluminescence detection].

Se Pu 2020 Aug;38(8):968-974

College of Chemistry and Chemical Engineering, Northwest Normal University, Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, Lanzhou 730070, China.

-Methylation of tranexamic acid yields an unique derivative, which generates strong co-luminescence signals in the presence of an electrochemiluminescence reagent such as Ru(bpy). Using this principle, we established a highly selective analytical method based on pre-column derivatization capillary electrophoresis coupled with electrogenerated chemiluminescence detection for determining the tranexamic acid content in essential cosmetics. The addition of a ternary ionic association gel, Mg-trehalose-SiO, in the components of background electrolyte greatly improved the electrophoretic separation efficiency. Read More

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[Simultaneous determination of amino acid and monoamine neurotransmitters in serum by high performance liquid chromatography coupled with precolumn derivatization].

Se Pu 2020 Aug;38(8):923-928

Medical Comprehensive Experimental Center, Hebei University, Baoding 071000, China.

Using -phthalaldehyde (OPA) as the derivatization reagent, a precolumn derivatized -high performance liquid chromatography (HPLC) method was developed for the simultaneous determination of amino acid neurotransmitters taurine (Tau), glutamic acid (Glu), glycine(Gly), and γ -aminobutyric acid (γ-GABA), as well as the monoamine neurotransmitter dopamine (DA), in serum samples. The samples and ethanol were mixed at a volume ratio of 1:2 (v/v) for protein precipitation. After centrifugation, the supernatant was withdrawn and blown to dryness using nitrogen. Read More

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[High-efficiency separation and analysis of monosaccharides in Pueraria polysaccharides by pressurized capillary electrochromatography].

Se Pu 2020 Nov;38(11):1323-1331

School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.

Pueraria polysaccharides have been proven to possess biological activities such as bacteriostasis, anti-oxidative, anti-tumor, and immunity boosting activities. The variation in the structure, composition, and amount of monosaccharides in these polysaccharides may lead to different spatial structures and biological activities. Therefore, extraction of Pueraria polysaccharides and determination of the monosaccharide composition are of great significance for activity analysis and quality control. Read More

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November 2020

Simultaneous Determination of Human Serum Albumin and Low-Molecular-Weight Thiols after Derivatization with Monobromobimane.

Molecules 2021 Jun 1;26(11). Epub 2021 Jun 1.

Department of Environmental Chemistry, Faculty of Chemistry, University of Lodz, Pomorska 163, 90-236 Lodz, Poland.

Biothiols are extremely powerful antioxidants that protect cells against the effects of oxidative stress. They are also considered relevant disease biomarkers, specifically risk factors for cardiovascular disease. In this paper, a new procedure for the simultaneous determination of human serum albumin and low-molecular-weight thiols in plasma is described. Read More

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LC-MS/MS characterisation and determination of dansyl chloride derivatised glyphosate, aminomethylphosphonic acid (AMPA), and glufosinate in foods of plant and animal origin.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 Jul 20;1177:122779. Epub 2021 May 20.

University of Tartu, Institute of Chemistry, Ravila 14a, 50411 Tartu, Estonia.

Glyphosate and other polar and acidic pesticides have been particularly studied due to the concerns over widespread and intensive use. The chemical properties of these compounds necessitate use of customised methods, such as derivatisation or ion exchange chromatography. These approaches present a compatibility problem with ESI-MS due to presence of salts and non-volatile compounds. Read More

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HPLC-UV and GC-MS Methods for Determination of Chlorambucil and Valproic Acid in Plasma for Further Exploring a New Combined Therapy of Chronic Lymphocytic Leukemia.

Molecules 2021 May 13;26(10). Epub 2021 May 13.

Department of Cancer Genetics with Cytogenetics Laboratory, Medical University of Lublin, 20-080 Lublin, Poland.

High performance liquid chromatography with ultra-violet detection (HPLC-UV) and gas chromatography-mass spectrometry (GC-MS) methods were developed and validated for the determination of chlorambucil (CLB) and valproic acid (VPA) in plasma, as a part of experiments on their anticancer activity in chronic lymphocytic leukemia (CLL). CLB was extracted from 250 µL of plasma with methanol, using simple protein precipitation and filtration. Chromatography was carried out on a LiChrospher 100 RP-18 end-capped column using a mobile phase consisting of acetonitrile, water and formic acid, and detection at 258 nm. Read More

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Evaluation of gamma-aminobutyric acid (GABA) production by Lactobacillus plantarum using two-step fermentation.

Bioprocess Biosyst Eng 2021 May 25. Epub 2021 May 25.

Department of Food Science and Biotechnology, College of Engineering, Global K-Food Research Center, Hankyong National University, Anseong-Si, 17579, Republic of Korea.

Lactic acid bacteria (Lactobacillus plantarum KCTC 3103) were fermented to produce gamma-aminobutyric acid (GABA). The conditions of the modified synthetic medium were optimized as 5 g/L glucose, 10 g/L yeast extract, 100 g/L rice bran extract, and 1.0 g/L ascorbic acid for GABA production. Read More

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Determination of free valproic acid concentration in 569 clinical samples by LC-MS/MS after HFCF-UF treatment.

Ther Drug Monit 2021 May 10. Epub 2021 May 10.

The Second Hospital of Hebei Medical University, China, Shijiazhuang 050000.

Objective: To perform therapeutic drug monitoring (TDM) of total and free plasma valproic acid (VPA) concentrations in clinical samples, and to analyze the related factors.

Methods: The total VPA concentration in plasma was determined by UHPLC with pre-column derivatization with α - bromoacetophenone, and the free VPA concentration was determined by LC-MS/MS after the plasma was treated by hollow fiber centrifugal ultrafiltration (HFCF-UF). Regression analysis was performed to examine the associations between free plasma VPA, total plasma VPA, and the plasma protein binding rate. Read More

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A novel simple and sensitive approach for determination of 1,1-dimethylhydrazine in aqueous samples by high performance liquid chromatography with ultraviolet and tandem mass spectrometric detection after derivatization with unsubstituted aromatic aldehydes.

Chemosphere 2021 Oct 3;280:130747. Epub 2021 May 3.

Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory, 1-3, GSP-1, Moscow, 119991, Russia.

In this work, simple, rapid and highly sensitive method of hazardous chemical 1,1-dimethylhydrazine (unsymmetrical dimethylhydrazine, UDMH) determination based on pre-column derivatization with unsubstituted aromatic aldehydes and reversed-phase high performance liquid chromatography-ultraviolet-tandem mass spectrometry (RP HPLC-UV-MS/MS) has been developed. Along with benzaldehyde, commercially available aromatic aldehydes, namely: 2-naphthaldehyde, 2-pyridinecarboxaldehyde, and 2-quinolinecarboxaldehyde, were used as derivatizing reagents in the analysis of hydrazines for the first time. The reactions were studied in a wide pH range by varying reaction time and other conditions. Read More

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October 2021

Determination of semicarbazide residue in human urine samples using liquid chromatography-tandem mass spectrometry.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2021 Jun 19;38(6):922-930. Epub 2021 Apr 19.

Taizhou Center for Disease Prevention and Control, Taizhou, China.

An ultra-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS) with pre-column derivatisation was developed and validated for the determination of semicarbazide in human urine. Urine samples were derivatised with 2-nitrobenzaldehyde and subsequently extracted with acetonitrile. Extracts were concentrated and then analysed by UPLC-MS/MS. Read More

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Stability of fumonisin B1 and its bioaccessibility in extruded corn-based products.

Mycotoxin Res 2021 May 22;37(2):161-168. Epub 2021 Mar 22.

Food Science & Technology, University of Nebraska-Lincoln, Lincoln, NE, USA.

Fumonisins are a group of mycotoxins commonly associated with corn-based products and require innovative alternatives to control exposure to its toxicity. The objective of this research was to determine the effect of amylose and resistant starch on fumonisin B1 (FB) levels in extruded corn-based products as well as the toxin bioaccessibility upon digestion. Cornmeal contaminated with FB (1. Read More

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Optimization and validation of a liquid chromatography-tandem mass spectrometry method for the determination of glyphosate in human urine after pre-column derivatization with 9-fluorenylmethoxycarbonyl chloride.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 May 5;1171:122616. Epub 2021 Mar 5.

Laboratory of Mass Spectrometry, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina.

In 2015, glyphosate was classified as "Group 2A - probably carcinogenic to humans" by the International Agency for Research on Cancer (IARC). Therefore, public concerns about the environmental and health risks of this substance have rapidly increased. Considering its toxicokinetic characteristics, urinary levels of glyphosate could be a powerful tool for human biomonitoring. Read More

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Performance Characteristics of refined LC-FLD and HILIC-MS/MS methods for the Determination of Paralytic Shellfish Toxins in Shrimp, Whelk and Crab.

J AOAC Int 2021 Mar 3. Epub 2021 Mar 3.

Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Road, The Nothe, Weymouth, Dorset, DT4 8UB, UK.

Background: PSP toxins have been reported in non-bivalve shellfish species, including crustaceans and gastropods. Routine surveillance of these species is currently conducted in parts of England. To date detection methods have not been validated for these matrices. Read More

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Reduction of the extra-column band dispersion by a slow transport and splitting of a sample band in isocratic reversed-phase liquid chromatography.

J Chromatogr A 2021 Mar 13;1641:461996. Epub 2021 Feb 13.

Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan; GL Sciences Inc., 237-2 Sayamagahara, Iruma, Saitama 358-0032, Japan. Electronic address:

Sample introduction method was studied to reduce the extra-column effect in reversed-phase HPLC. Slow transport of a sample band (SToSB) in the pre-column space followed by the introduction of the band into the column at a near-optimum flow rate resulted in larger plate counts for a 1.0 mmID, 5 cm long column as much as 1. Read More

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Determination of Total Proteinogenic Amino Acids and Taurine by Pre-column Derivatization and UHPLC: Single Laboratory Validation, First Action Official MethodSM 2019.09.

J AOAC Int 2021 May;104(2):431-446

AsureQuality Limited, PO Box 41, Shortland Street, Auckland 1140, New Zealand.

Background: A method has been developed and validated for selective, accurate, and precise determination of total proteinogenic amino acids and taurine from infant formula and adult/pediatric nutritional formulas (powders, ready-to-feed liquids, and liquid concentrates). The method was reviewed by the AOAC INTERNATIONAL SPIFAN Expert Review Panel (ERP) during the 133rd AOAC Annual Meeting and Expo on September 7, 2019 in Denver, CO, USA, and was recommended to First Action Official MethodsSM status.

Objective: The method involves protein hydrolysis to amino acids, a simple pre-column derivatization of amino acids and separation of derivatized amino acids by UHPLC. Read More

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Serum D-serine levels are altered in early phases of Alzheimer's disease: towards a precocious biomarker.

Transl Psychiatry 2021 01 26;11(1):77. Epub 2021 Jan 26.

Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy.

D-Serine acts as a co-agonist of N-methyl-D-aspartate receptors (NMDAR) which appear overactivated in AD, while D-aspartate is a modulatory molecule acting on NMDAR as a second agonist. The aim of this work is to clarify whether the levels of these D-amino acids in serum are deregulated in AD, with the final goal to identify novel and precocious biomarkers in AD. Serum levels of L- and D-enantiomers of serine and aspartate were determined by HPLC using a pre-column derivatization procedure and a selective enzymatic degradation. Read More

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January 2021

Determination of -D-glutamyl--diaminopimelic acid in rumen fluid of dairy cows by pre-column chiral derivatization-HPLC.

Anim Biotechnol 2021 Jan 24:1-17. Epub 2021 Jan 24.

Ministry of Education Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, P. R. China.

High concentrate (HC) diet feeding leads to the lysis of rumen microbes and the release of hazardous metabolites, which can trigger inflammatory responses, thereby impairing dairy cow health and production. -D-glutamyl--diaminopimelic acid (iE-DAP), which constitutes the peptidoglycan (PGN) layer of bacteria, is the minimum PGN structure capable of activating inflammatory signaling pathways. This research paper aimed to determine the iE-DAP concentration and investigate the effects of an HC diet on the concentration of iE-DAP in the rumen fluid of dairy cows. Read More

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January 2021

Determination of monosaccharides in Lycium barbarum fruit polysaccharide by an efficient UHPLC-QTRAP-MS/MS method.

Phytochem Anal 2021 Jan 21. Epub 2021 Jan 21.

School of Pharmacy, Anhui University of Chinese Medicine, Hefei, China.

Introduction: Pre-column derivatisation using 1-phenyl-3-methyl-5-pyrazolone (PMP) is a common method for monosaccharide determination. Herein, a specific ultra-high-performance liquid chromatography quadrupole trap tandem mass spectrometry (UHPLC-QTRAP-MS/MS) method was developed and used for the determination of monosaccharide composition of Lycium barbarum polysaccharide (LBP).

Objective: Exploration of a new efficient method for monosaccharide determination. Read More

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January 2021

Multifunctional properties and safety evaluation of lactic acid bacteria and yeasts associated with fermented cereal doughs.

World J Microbiol Biotechnol 2021 Jan 21;37(2):34. Epub 2021 Jan 21.

Laboratoire de Sciences des Aliments, Faculté des Sciences Agronomiques, Université d'Abomey-Calavi, 03, BP 2819, Jéricho, Cotonou, Benin.

Spontaneous cereal fermentations involve diverse lactic acid bacteria (LAB) and yeasts which may include multifunctional and safe or unsafe strains. This study assessed acidification ability, safety, antifungal activity and free amino acids release ability of LAB and yeasts previously isolated from spontaneously fermented cereal doughs in Benin. Fourteen LAB and thirteen yeast strains were studied in liquid media and/or in a model cereal dough prepared in laboratory conditions. Read More

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January 2021

Development of a selective three-dimensional HPLC system for enantiomer discriminated analysis of lactate and 3-hydroxybutyrate in human plasma and urine.

J Pharm Biomed Anal 2021 Feb 26;195:113871. Epub 2020 Dec 26.

Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan; School of Pharmacy, Taipei Medical University, 250 Wuxing Street, Taipei, 11031, Taiwan. Electronic address:

For the enantiomer discriminated determination of lactate (LA) and 3-hydroxybutyrate (3HB) in various complicated samples, a three-dimensional HPLC (3D-HPLC) system has been designed and developed by investigating the separation of the target analytes from unknown substances observed in the real target matrices. LA and 3HB were pre-column derivatized with 4-nitro-7-piperazino-2,1,3-benzoxadiazole for the sensitive fluorescence detection and introduced into the 3D-HPLC system composed of reversed-phase, mixed-mode and enantioselective separations. The present method was validated by calibration curves, precision and accuracy using standard solutions and human samples, and sufficient values were obtained. Read More

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February 2021

[Determination of the butanone in urine by gas chromatography with precolumn derivation].

Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 2020 Dec;38(12):940-943

Hangzhou Occupational Disease Prevention and Control Hospital, Hangzhou 310014, China.

To establish a method for determination of the butanone in urine by gas chromatography (GC) with pre-column derivation. For detecting of butanone in urine, potassium iodide and potassium dichromate were added into urine under acidic condition, sample derivatization was undertaken in 50 ℃ water bath for 60 min and the iodine butanone was extracted with n-hexane. After the sodium thiosulfate solution was used to remove excess iodine, urine samples were centrifuged at 10000 r/min for 5 min, then the supernatant was analyzed using temperature rising programming with the Agilent Hp-5 column (30 m×0. Read More

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December 2020

Application of Six Detection Methods for Analysis of Paralytic Shellfish Toxins in Shellfish from Four Regions within Latin America.

Mar Drugs 2020 Dec 3;18(12). Epub 2020 Dec 3.

Laboratory of Marine Toxins, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago 8320000, Chile.

With the move away from use of mouse bioassay (MBA) to test bivalve mollusc shellfish for paralytic shellfish poisoning (PSP) toxins, countries around the world are having to adopt non-animal-based alternatives that fulfil ethical and legal requirements. Various assays have been developed which have been subjected to single-laboratory and multi-laboratory validation studies, gaining acceptance as official methods of analysis and approval for use in some countries as official control testing methods. The majority of validation studies conducted to date do not, however, incorporate shellfish species sourced from Latin America. Read More

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December 2020

Sensitive quantification of dipicolinic acid from bacterial endospores in soils and sediments.

Environ Microbiol 2021 Mar 21;23(3):1397-1406. Epub 2020 Dec 21.

Department of Biological Sciences, University of Calgary, Calgary, T2N 1N4, Canada.

Endospore-forming bacteria make up an important and numerically significant component of microbial communities in a range of settings including soils, industry, hospitals and marine sediments extending into the deep subsurface. Bacterial endospores are non-reproductive structures that protect DNA and improve cell survival during periods unfavourable for bacterial growth. An important determinant of endospores withstanding extreme environmental conditions is 2,6-pyridine dicarboxylic acid (i. Read More

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Isolation, structure identification and hepatoprotective activity of a polysaccharide from Sabia parviflora.

Bioorg Med Chem Lett 2021 01 27;32:127719. Epub 2020 Nov 27.

Hubei Key Laboratory of Natural Products Research and Development, Key Laboratory of Functional Yeast (China National Light Industry), College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, PR China. Electronic address:

The extraction, purification, structure and hepatoprotective activity of a homogenous polysaccharide (SPS60) from Sabia parviflora were investigated. SPS60 was screened after purification with Sephadex G-100 and showed the excellent hepatoprotective activity. Its structural characteristics were investigated by Time of flight mass spectrometry (TOF-MS), PMP Pre-column derivatization-HPLC (PMP-HPLC), nuclear magnetic resonance (NMR) spectroscopy and Atomic Force Microscopy (AFM). Read More

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January 2021

Quantification of the bisphosphonate alendronate using capillary electrophoresis mass spectrometry with dynamic pH barrage junction focusing.

Electrophoresis 2021 Feb 16;42(4):350-359. Epub 2020 Dec 16.

Department of Chemistry, The University of British Columbia, Vancouver, Canada.

A quantitative method was developed for the direct identity confirmation and quantification of alendronate using CE-MS combined with a pH-assisted focusing technique, dynamic pH barrage junction focusing. A pH-induced variation in electrophoretic mobility led to online focusing of alendronate at the sample/pH barrage boundary, significantly improving the detection sensitivity. In addition, the use of a flow-through microvial CE electrospray interface and the multiple reaction monitoring mode of MS further improved the specificity and quantification capability of this technology. Read More

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February 2021