In this work,a new pyrylium derivatization-assisted liquid chromatography-mass spectrometry(LC-MS)method was developed for metabolite profiling of the glutathione anabolic pathway(GAP)in cancer tissues and cells.The p...In this work,a new pyrylium derivatization-assisted liquid chromatography-mass spectrometry(LC-MS)method was developed for metabolite profiling of the glutathione anabolic pathway(GAP)in cancer tissues and cells.The pyrylium salt of 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate(DMMIC)was used to label the amino group of metabolites,and a reductant of dithiothreitol(DTT)was employed to stabilize the thiol group.By combining DMMIC derivatization with LC-MS,it was feasible to quantify the 13 main metabolites on the GAP in complex biological samples,which had good linearity(R^(2)=0.99810.9999),precision(interday precision of 1.6%e19.0%and intraday precision of 1.4%e19.8%)and accuracy(83.4%-115.7%).Moreover,the recovery assessments in tissues(82.5%e107.3%)and in cells(98.1%e118.9%)with GSH-^(13)C2,^(15)N,and Cys-^(15)N demonstrated the reliability of the method in detecting tissues and cells.Following a methodological evaluation,the method was applied successfully to investigate difference in the GAP between the carcinoma and para-carcinoma tissues of esophageal squamous cell carcinoma(ESCC)and the effect of p-hydroxycinnamaldehyde(CMSP)on the GAP in KYSE150 esophageal cancer cells.The results demonstrate that the developed method provides a promising new tool to elucidate the roles of GAP in physiological and pathological processes,which can contribute to research on drugs and diseases.展开更多
Amino-containing compounds,including amino acids,aliphatic amines,aromatic amines,small peptides and catecholamines,are involved in various biological processes and play vital roles in multiple metabolic pathways.Prev...Amino-containing compounds,including amino acids,aliphatic amines,aromatic amines,small peptides and catecholamines,are involved in various biological processes and play vital roles in multiple metabolic pathways.Previous studies indicated that some amino-containing metabolites are significant diagnostic and prognostic biomarkers of gastric cancer.However,the discovery of precise biomarkers for the preoperative diagnosis of gastric cancer is still in an urgent need.Herein,we established a polarityregulated derivatization method coupled with liquid chromatography-mass spectrometry(LC-MS)for amino-containing metabolites profiling in the serum samples of patients with gastric cancer and healthy controls,based on our newly designed and synthesized derivatization reagent(S)-3-(1-(diisopropoxyphosphoryl)pyrrolidine-2-carboxamido)-N-hydroxysuccinimidyl ester(3-DP-NHS).Enhanced separation efficiency and detection sensitivity for amino-containing metabolites were achieved after derivatization.This method exhibited good linearity,recovery,intra-and inter-day precision and accuracy.Only 5 mL serum is needed for untargeted analysis,enabling 202 amino-containing metabolites to be detected.Statistical analysis revealed altered amino acid metabolisms in patients with gastric cancer.Furthermore,ultra high performance liquid chromatography coupled with mass spectrometry(UHPLCMS/MS)analysis quantification revealed increased serum levels of tryptamine and decreased concentrations of arginine and tryptophan in patients with gastric cancer.Receiver operating characteristic(ROC)curves indicated that an increased tryptamine/tryptophan ratio could serve as a potential biomarker for gastric cancer diagnosis.This study demostrated the possibility of using serum amino acid biomarkers for gastric cancer diagnosis,providing new avenues for the treatment of gastric cancer.展开更多
A selective precolumn derivatization liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was d...A selective precolumn derivatization liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was derivatized by o-phthalaldehyde/3-mercaptopropionic acid. Chromatographic separation was performed on a Phenomenex ODS column (150 mm 4.6 mm, 5 mm) using linear gradient elution by a mobile phase consisting of methanol (A), and an aqueous solution containing 0.2% ammonium acetate and 0.1% formic acid (B) at a flow rate of 1 mL/min. Tolterodine tartrate was used as the internal standard (IS). With protein precipitation by acetonitrile and then the simple one-step derivatization, a sensitive bio-assay was achieved with the lower limit of quantitation (LLOQ) as low as 12 ng/mL for plasma. The standard addition calibration curves suitable for clinical sample analysis showed good linearity over the range of 0.012-8.27 mg/mL in plasma and 1.80-84.1 mg/mL in urine. The fully validated method has been successfully applied to a pharmacokinetic study of compound glucosamine sulfate dispersible tablets in health Chinese volunteers receiving single oral doses at 500, 1000 and 1500 mg of glucosamine sulfate, as well as multiple oral doses of 500 mg t.i.d. for 7 consecutive days.展开更多
This paper reviews studies on dissolution, derivatization, and nanomaterial processing of chitin using an ionic liquid as useful media. Because chitin is the second most abundant polysaccharide on the earth after cell...This paper reviews studies on dissolution, derivatization, and nanomaterial processing of chitin using an ionic liquid as useful media. Because chitin is the second most abundant polysaccharide on the earth after cellulose, there is major interest in conversion of native chitin resources into various useful materials after proper dissolution in suitable solvents. For the derivatization and nanomaterial processing of chitin, the author has been focusing on ionic liquids because which have been found to be used as good solvents for cellulose in a past decade. The author found that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), dissolved chitin in concentrations up to 4.8 wt% and mixtures of the higher amounts of chitin with AMIMBr gave ion gels. Acetylation, the simplest derivatization, of chitin using acetic anhydride was achieved in the AMIMBr solvent under mild conditions. Furthermore, the chitin nanofibers were fabricated by regeneration technique from the chitin ion gel with AMIMBr using methanol. Moreover, filtration of the chitin nanofiber dispersion with methanol was carried out to give a chitin nanofiber film. The chitin nanofiber-poly(vinyl alcohol) composite film was also prepared from the ion gel by co-regeneration method.展开更多
A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were...A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.展开更多
A sensitive and rapid high performance liquid chromatography-mass spectrometry(HPLC-MS)method was developed and validated for simultaneous quantifcation of ten steroid hormones,including estrogens,androgens,progestero...A sensitive and rapid high performance liquid chromatography-mass spectrometry(HPLC-MS)method was developed and validated for simultaneous quantifcation of ten steroid hormones,including estrogens,androgens,progesterones,and corticosteroids four classes of steroids.The following ten steroid hormones were analyzed:progesterone,21-deoxycortisol,estrone,4-androstenedione,testosterone,dihydro-testosterone,androstenone,dehydroepiandrosterone,corticosterone and cortisone.Stable deuterated isotopes were used as internal standards for quantifcation.Sample preparation with and without derivatization were performed after liquid-liquid extraction,and the corresponding results were compared according to sensitivity and selectivity.Hydroxylamine derivatization was found to improve the ionization efciency of the analytes for electrospray ionization MS analysis.The gradient of mobile phase and experimental parameters for HPLC separation were optimized.The lower limits of quantifcation were in the range of 0.05-5 ng mL^(−1) with wide linear range for the ten steroid hormones.The intra-day precision<11.1%and recovery of 84.5-120% with negligible matrix efect were achieved,where within the acceptance limits of the FDA guideline.Total HPLC-MS analysis time was 6 min.This method enables simultaneous quantifcation of steroids in human serum.It will be helpful for the serum steroid profling in order to understand various endocrinology diseases.展开更多
Chlorophenols (2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol and 2,4, 6-trichlorophenol) may be presented in natural waters or drinking water as a result of disinfection processes involving ch...Chlorophenols (2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol and 2,4, 6-trichlorophenol) may be presented in natural waters or drinking water as a result of disinfection processes involving chlorination, or as contaminants derived from domestic products, industrial operations and agricultural chemicals. A previous HPLC-UV method for determination of phenol and five chlorophenols in tap water using 4-fluoro-7-nitro-2,1,3-benzoxadiaole as a UV labeling reagent shows limited sensitivity. Here, we present an improved HPLC-fluorescence detection method for simultaneous determination of phenol and the above chlorophenols in tap water after pre-column derivatization with 3-chlorocarbonyl-6,7-dimethoxy-1-methyl-2(1H)-quino- xalinone (DMEQ-COCl), using a short, narrow column (50 × 2.1 mm i.d., packed with 5 μm particles of C18 material) to improve the sensitivity. Standard samples containing the compounds are derivatized with DMEQ-COCl in borate buffer (pH 9.0) at room temperature for 3 mins. The response is linear in the concentration range of 0.01 - 0.05 to 0.5 mg/L with r2 values ≥0.9967 for all compounds. The lower limits of detection are 0.001 to 0.008 mg/L, and the coefficients of variation are less than 8.8%. The recovery values from tap water spiked with standard samples are satisfactory. The present method is suitable for examining whether or not tap water samples are contaminated with phenol and chlorophenols in excess of regulatory values.展开更多
A convenient hydride derivatization procedure of methyl\|and ethylmercury chlorides to volatile hydrides was reported. In sealed vials methylmercury and ethylmercury compounds in acidic aqueous solutions were converte...A convenient hydride derivatization procedure of methyl\|and ethylmercury chlorides to volatile hydrides was reported. In sealed vials methylmercury and ethylmercury compounds in acidic aqueous solutions were converted into their volatile forms by the reaction with potassium tetrahydroborate(KBH 4) and elvolved to the headspace of the vials. The gaseous analytes in the headspace were extracted and concentrated by solid phase microextraction(SPME) and injected into gas chromatography (GC) for separation and identified by mass selective detector(MS).展开更多
Raspberry ketone {RK, 4-(4-hydroxyphenyl)butan-2-one} is a natural compound contained in raspberry, and is added to cosmetics for skin whitening. It is very important to measure the RK level in cosmetics for quality a...Raspberry ketone {RK, 4-(4-hydroxyphenyl)butan-2-one} is a natural compound contained in raspberry, and is added to cosmetics for skin whitening. It is very important to measure the RK level in cosmetics for quality assessment, since RK structurally resembles 4-(4-hydroxyphenyl)-2-butanol, which causes leukoderma on consumers’ skin. Here, we present a simple HPLC-fluorescence method for determination of RK in a fragrance mist by pre-column derivatization with 4-hydrazino-7-nitro-2,1,3-benzoxadiazole hydrazine (NBD-H), which reacts with the carbonyl group of RK. The NBD-RK derivative was eluted from a reversed-phase ODS column, and detected with excitation at 470 nm and emission at 550 nm. The retention time of NBD-RK derivative obtained by reaction with NBD-H at 80°C for 20 min was 10.3 min. The standard curve was linear in the range of 0.2 to 10 μg/mL, with a correlation coefficient (r<sup>2</sup>) value of 0.9980. The lower limit of detection was 0.018 μg/mL (absolute amount of 1.8 pmol). The coefficients of variation were less than 8.1%. The content of RK in fragrance mist (1.00 mL) was 1.18 ± 0.07 mg (range: 1.12 to 1.28 mg, n = 5). Recovery tests were satisfactory (83.9% ± 3.9%;range: 79.6 to 88.8%, n = 5).展开更多
A self-ordered ring(SOR) fluorescence microscopic imaging technique has been developed for the determination of trace amounts of sulfadiazine based on its derivatization with fluorescamine.In the presence of HAc-NaAc ...A self-ordered ring(SOR) fluorescence microscopic imaging technique has been developed for the determination of trace amounts of sulfadiazine based on its derivatization with fluorescamine.In the presence of HAc-NaAc buffer solution(pH 3.12) and polyvinyl alcohol-124(PVA-124),the droplet containing fluorescamine derivatized sulfadiazine can form a SOR on the solid support after solvent evaporation with the diameter of 1.86mm and its ring belt width of 54.9 μ m.The quantitative analysis of sulfadiazine is achieved with the linear range of 7.8×10-14 ～1.8×10-12 mol·ring-1(3.9×10-7 ～9.0×10-6 mol·L-1) and detection limit of 7.8×10-15 mol·ring-1(3.9×10-8 mol·L-1) when 0.2 μ L droplet was spotted.The technique has been satisfactorily applied to the determination of sulfadiazine in the tablet,synthetic sample and residues in six different milk samples with the recoveries of 91.0%～105.8%,respectively,and RSDs less than 4.4%.展开更多
A sensitive liquid chromatographic mcthod for the detection of andno acids with precolumn fluorescence derivatization with acridone-N-acetyl chloride has been developed. Andno acid derivatives were eluted in 4o ndn wi...A sensitive liquid chromatographic mcthod for the detection of andno acids with precolumn fluorescence derivatization with acridone-N-acetyl chloride has been developed. Andno acid derivatives were eluted in 4o ndn with good reproducibility. The reIative standard deviations (n=6) at an analytical concentration of 50 pmol are < 4%. The method described is also suitable for the analysis of andno acids in different biological samples.展开更多
Endogenous ribonucleotides(RNs)and deoxyribonucleotides(dRNs)are important metabolites related to the pathogenesis of many diseases.In light of their physiological and pathological significances,a novel and sensitive ...Endogenous ribonucleotides(RNs)and deoxyribonucleotides(dRNs)are important metabolites related to the pathogenesis of many diseases.In light of their physiological and pathological significances,a novel and sensitive pre-column derivatization method with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide(MTBSTFA)was developed to determine RNs and dRNs in human cells using high-performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).A one-step extraction of cells with 85%methanol followed by a simple derivatization reaction within 5 min at room temperature contributed to shortened analysis time.The derivatives of 22 nucleoside mono-,di-and tri-phosphates were retained on the typical C;column and eluted by ammonium acetate and acetonitrile in 9 min.Under these optimal conditions,good linearity was achieved in the tested calibration ranges.The lower limit of quantitation(LLOQ)was determined to be 0.1-0.4μM for the tested RNs and 0.001-0.1μM for dRNs.In addition,the precision(CV)was<15%and the RSD of stability was lower than 10.4%.Furthermore,this method was applied to quantify the endogenous nucleotides in human colorectal carcinoma cell lines HCT 116 exposed to 10-hydroxycamptothecin.In conclusion,our method has proven to be simple,rapid,sensitive,and reliable.It may be used for specific expanded studies on intracellular pharmacology in vitro.展开更多
Structural derivatization of natural products has been a continuing and irreplaceable source of novel drug leads.Natural phenols are a broad category of natural products with wide pharmacological activity and have off...Structural derivatization of natural products has been a continuing and irreplaceable source of novel drug leads.Natural phenols are a broad category of natural products with wide pharmacological activity and have offered plenty of clinical drugs.However,the structural complexity and wide variety of natural phenols leads to the difficulty of structural derivatization.Skeleton analysis indicated most types of natural phenols can be structured by the combina-tion and extension of three common fragments containing phenol,phenylpropanoid and benzoyl.Based on these fragments,the derivatization strategies of natural phenols were unified and comprehensively analyzed in this review.In addition to classical methods,advanced strategies with high selectivity,efficiency and practicality were empha-sized.Total synthesis strategies of typical fragments such as stilbenes,chalcones and flavonoids were also covered and analyzed as the supplementary for supporting the diversity-oriented derivatization of natural phenols.展开更多
A rapid and reproducible method has been developed for the simultaneous quantification of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in rat brain microdialysates. Derivatization was processed through red...A rapid and reproducible method has been developed for the simultaneous quantification of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in rat brain microdialysates. Derivatization was processed through reductive amination with butyraldehyde and sodium cyanoborohydride at 60℃ for 80 min incubation. Dibutylated monoamine neurotransmitters (MANTs) were directly analyzed with ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The chromatographic run time was shorter (2.1 min/sample) than previous studies [15] [18] [20]. Good linearity (R2 > 0.99) was obtained for DA, NE and 5-HT in the range of 25 - 5000 pg/mL, 5 - 1000 pg/mL and 2.5 - 500 pg/mL, respectively. Acceptable precision (CV, 8.5% - 13.4%) as well as accuracy (recovery, 94.1% - 106.8%) could be acquired by analysis of six batches of quality control samples (QCs) at four different concentrations, which demonstrated the reliability and reproducibility of current method. This method was successfully applied to the simultaneous determination of DA, NE and 5-HT in rat brain microdialysates, where basal levels as well as elevated levels after dosing with amphetamine (AMPH) were quantified for all three MANTs. This study provides a simple and rapid way to analyze MANTs in the biofluid in the future.展开更多
High performance liquid chromatography method for the separation of a series of chiral benzyl alcohols on N-(3,5-dinitrobenzoyl)-D-phenylglycine stationary phase (Macherey Nagel, Chiral-2) after pre-column achiral der...High performance liquid chromatography method for the separation of a series of chiral benzyl alcohols on N-(3,5-dinitrobenzoyl)-D-phenylglycine stationary phase (Macherey Nagel, Chiral-2) after pre-column achiral derivatization was developed. Cheap and easy available aromatic acid chlorides were used as derivatization agents. Good to excellent separations of the enantiomers were achieved in all cases in relatively short analytical runs. It was shown that the enantiorecognition depends on the substituents both in the starting alcohol and in the acid chloride. The method presents an efficient alternative to the direct analyses on polysaccharide and cyclodextrine-derived stationary phases.展开更多
Use of new amphetamine-type stimulants (ATS) as designer drugs is a serious problem worldwide. ATS are used in tablet, capsule, and powder forms, and can be mixed with other drugs. There is little information availabl...Use of new amphetamine-type stimulants (ATS) as designer drugs is a serious problem worldwide. ATS are used in tablet, capsule, and powder forms, and can be mixed with other drugs. There is little information available on how these new drugs are metabolized or their ability to inhibit the metabolism of co-administered drugs. This study aimed to investigate the metabolism of six 4-substituted analogs of methamphetamine (MA), and their potential inhibition of MA metabolism. The metabolism of MA and the 4-substituted MAs was examined in vitro using human metabolic enzymes. Metabolite analyses were performed using trifluoroacetyl derivatization and GC-MS. The experiments showed that cytochrome P450 2D6 (CYP2D6) was involved in the major metabolic pathway of MA, where it catalyzed N-demethylation of 4-fluoromethamphetamine (4-FMA), 4-chloromethamphetamine (4-CMA), 4-bromomethamphetamine (4-BMA), 4-iodomethamphetamine (4-IMA) and 4-nitromethamphetamine (4-NMA), and O-demethylation of 4-methoxymethamphetamine (4-MMA). The half maximal inhibitory concentration (IC50) values for CYP2D6 using MA as substrate were different for each of the 4-substituted MAs. The strongest inhibitors of amphetamine production from MA were, in order, 4-IMA, 4-BMA, 4-CMA, 4-MMA, 4-FMA, and 4-NMA. The same order was observed for the IC50 values for inhibition of p-hydroxymethamphetamine production from MA, except for the IC50 of 4-MMA. The IC50 values of 4-IMA were lower than the IC50 values of fluoxetine and higher than that of quinidine. The results of this study imply that the risk of illicit drug interactions fluctuates so widely that unintentional fatal drug poisonings could occur.展开更多
This work aimed to study the derivatization unprecedented of glyphosate and AMPA solutions using N,O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) combined with trimethylchlorosilane (TMCS), evaluating the compositio...This work aimed to study the derivatization unprecedented of glyphosate and AMPA solutions using N,O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) combined with trimethylchlorosilane (TMCS), evaluating the composition of the reaction medium, use of ultrasound, volume of BSTFA:pyridine and pH of the reaction medium. From this study it was inferred that the reaction medium was composed of BSTFA:pyridine in ratio 60:100, respectively, without ultrasonic vibration and pH adjustment that provide optimal conditions for analysis by GC-MS. Furthermore, the methodology used was simple and fast, and that was the most practical method commonly used.展开更多
The purpose of this study is to develop an HPLC-UV (280 nm) method for simultaneous determination of phenol, five chlorophenols (2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, and 2,4,6-trichl...The purpose of this study is to develop an HPLC-UV (280 nm) method for simultaneous determination of phenol, five chlorophenols (2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, and 2,4,6-trichlorophenol), and three phenylphenols (2-phenylphenol, 3-phenylphenol, and 4-phenylphenol) in tap water after pre-column derivatization with 4-nitrobenzoyl chloride. Standard curves were obtained after derivatization with 4-nitrobenzoyl chloride in borate buffer (pH 8.5) at 50°C for 1 min. The nine 4-nitrobenzoyl derivatives were well separated in less than 15 min on a Cholester column. Calibration plots were linear in the range of 0.02 ~ 0.12 to 0.9 mg/L, with r2 values ≥0.9928, for all compounds. The lower limits of detection were 0.006 to 0.05 mg/L. The coefficients of variation were less than 12.0%. The recovery values from tap water spiked with a standard mixture of test compounds were satisfactory. While the levels of phenol, five chlorophenols, and three phenylphenols in tap water were below the lower limit of determination, our method is expected to be useful for monitoring and/or identifying environmental water samples that are contaminated with these compounds, i.e., for assessing compliance with the official guidelines of the World Health Organization.展开更多
A highly sensitive HPLC method for the detection of amino acids and oligopeptides with 9-acridine formyl chloride by. pre-column fluorescence derivatization has been developed. Glycine. glycylglycine, histidine, trigl...A highly sensitive HPLC method for the detection of amino acids and oligopeptides with 9-acridine formyl chloride by. pre-column fluorescence derivatization has been developed. Glycine. glycylglycine, histidine, triglycine and glutathione were separated on a reversed-phase C18 column with methanol-water-triethylamine eluent, derivatization and chromatographic conditions were optimized . The five derivatives were eluted in 28 min with a good reproducibility. Linear range of the calibration graph was 0.08-260 nmol/ml-1. The relative standard deviations(n=6) are < 5%. Detection limits (signal-to-noise ratio=3) for the five derivatives are 20-40展开更多
基金We thank the Shanghai Municipal Committee of Science and Technology(Grant Nos.:20XD1423400,23ZR1460900 and 20DZ2201100)Shanghai Municipal Health Commission/Shanghai Municipal Administration of Traditional Chinese Medicine(Grant No.:ZY(2021e2023)-0501)+2 种基金Shanghai Science and Technology Development Fund from Central Leading Local Government(Grant No.:YDZX20223100001004)National Natural Science Foundation of China(Grant No.:21672249)Expenditure Budget Program of Shanghai University of Traditional Chinese Medicine(Grant Nos.:2020LK051,and 2021LK001).
文摘In this work,a new pyrylium derivatization-assisted liquid chromatography-mass spectrometry(LC-MS)method was developed for metabolite profiling of the glutathione anabolic pathway(GAP)in cancer tissues and cells.The pyrylium salt of 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate(DMMIC)was used to label the amino group of metabolites,and a reductant of dithiothreitol(DTT)was employed to stabilize the thiol group.By combining DMMIC derivatization with LC-MS,it was feasible to quantify the 13 main metabolites on the GAP in complex biological samples,which had good linearity(R^(2)=0.99810.9999),precision(interday precision of 1.6%e19.0%and intraday precision of 1.4%e19.8%)and accuracy(83.4%-115.7%).Moreover,the recovery assessments in tissues(82.5%e107.3%)and in cells(98.1%e118.9%)with GSH-^(13)C2,^(15)N,and Cys-^(15)N demonstrated the reliability of the method in detecting tissues and cells.Following a methodological evaluation,the method was applied successfully to investigate difference in the GAP between the carcinoma and para-carcinoma tissues of esophageal squamous cell carcinoma(ESCC)and the effect of p-hydroxycinnamaldehyde(CMSP)on the GAP in KYSE150 esophageal cancer cells.The results demonstrate that the developed method provides a promising new tool to elucidate the roles of GAP in physiological and pathological processes,which can contribute to research on drugs and diseases.
基金supported by the Science and Technology Development Fund,Macao SAR(Grant No.:0025/2021/A1)funded by Natural Science Foundation of Shenzhen(Grant No.:JCYJ20190808115003699)Major Medical Projects in Zhongshan(Grant No.:2017B1003).
文摘Amino-containing compounds,including amino acids,aliphatic amines,aromatic amines,small peptides and catecholamines,are involved in various biological processes and play vital roles in multiple metabolic pathways.Previous studies indicated that some amino-containing metabolites are significant diagnostic and prognostic biomarkers of gastric cancer.However,the discovery of precise biomarkers for the preoperative diagnosis of gastric cancer is still in an urgent need.Herein,we established a polarityregulated derivatization method coupled with liquid chromatography-mass spectrometry(LC-MS)for amino-containing metabolites profiling in the serum samples of patients with gastric cancer and healthy controls,based on our newly designed and synthesized derivatization reagent(S)-3-(1-(diisopropoxyphosphoryl)pyrrolidine-2-carboxamido)-N-hydroxysuccinimidyl ester(3-DP-NHS).Enhanced separation efficiency and detection sensitivity for amino-containing metabolites were achieved after derivatization.This method exhibited good linearity,recovery,intra-and inter-day precision and accuracy.Only 5 mL serum is needed for untargeted analysis,enabling 202 amino-containing metabolites to be detected.Statistical analysis revealed altered amino acid metabolisms in patients with gastric cancer.Furthermore,ultra high performance liquid chromatography coupled with mass spectrometry(UHPLCMS/MS)analysis quantification revealed increased serum levels of tryptamine and decreased concentrations of arginine and tryptophan in patients with gastric cancer.Receiver operating characteristic(ROC)curves indicated that an increased tryptamine/tryptophan ratio could serve as a potential biomarker for gastric cancer diagnosis.This study demostrated the possibility of using serum amino acid biomarkers for gastric cancer diagnosis,providing new avenues for the treatment of gastric cancer.
文摘A selective precolumn derivatization liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was derivatized by o-phthalaldehyde/3-mercaptopropionic acid. Chromatographic separation was performed on a Phenomenex ODS column (150 mm 4.6 mm, 5 mm) using linear gradient elution by a mobile phase consisting of methanol (A), and an aqueous solution containing 0.2% ammonium acetate and 0.1% formic acid (B) at a flow rate of 1 mL/min. Tolterodine tartrate was used as the internal standard (IS). With protein precipitation by acetonitrile and then the simple one-step derivatization, a sensitive bio-assay was achieved with the lower limit of quantitation (LLOQ) as low as 12 ng/mL for plasma. The standard addition calibration curves suitable for clinical sample analysis showed good linearity over the range of 0.012-8.27 mg/mL in plasma and 1.80-84.1 mg/mL in urine. The fully validated method has been successfully applied to a pharmacokinetic study of compound glucosamine sulfate dispersible tablets in health Chinese volunteers receiving single oral doses at 500, 1000 and 1500 mg of glucosamine sulfate, as well as multiple oral doses of 500 mg t.i.d. for 7 consecutive days.
文摘This paper reviews studies on dissolution, derivatization, and nanomaterial processing of chitin using an ionic liquid as useful media. Because chitin is the second most abundant polysaccharide on the earth after cellulose, there is major interest in conversion of native chitin resources into various useful materials after proper dissolution in suitable solvents. For the derivatization and nanomaterial processing of chitin, the author has been focusing on ionic liquids because which have been found to be used as good solvents for cellulose in a past decade. The author found that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), dissolved chitin in concentrations up to 4.8 wt% and mixtures of the higher amounts of chitin with AMIMBr gave ion gels. Acetylation, the simplest derivatization, of chitin using acetic anhydride was achieved in the AMIMBr solvent under mild conditions. Furthermore, the chitin nanofibers were fabricated by regeneration technique from the chitin ion gel with AMIMBr using methanol. Moreover, filtration of the chitin nanofiber dispersion with methanol was carried out to give a chitin nanofiber film. The chitin nanofiber-poly(vinyl alcohol) composite film was also prepared from the ion gel by co-regeneration method.
基金Supported by Open Project of the Key Laboratory of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base(201603)Basic Research Project of Application of Suzhou City(SNG201622)
文摘A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.
基金National Natural Science Foundation of China(Grant No.21275167)the Natural Science Foundation of Hubei Province(Grant No.2014CFA025)the Preferred Research Foundation for the Returned Overseas Scholars from Ministry of Human Resources and Social Security of the People’s Republic of China for financial support.
文摘A sensitive and rapid high performance liquid chromatography-mass spectrometry(HPLC-MS)method was developed and validated for simultaneous quantifcation of ten steroid hormones,including estrogens,androgens,progesterones,and corticosteroids four classes of steroids.The following ten steroid hormones were analyzed:progesterone,21-deoxycortisol,estrone,4-androstenedione,testosterone,dihydro-testosterone,androstenone,dehydroepiandrosterone,corticosterone and cortisone.Stable deuterated isotopes were used as internal standards for quantifcation.Sample preparation with and without derivatization were performed after liquid-liquid extraction,and the corresponding results were compared according to sensitivity and selectivity.Hydroxylamine derivatization was found to improve the ionization efciency of the analytes for electrospray ionization MS analysis.The gradient of mobile phase and experimental parameters for HPLC separation were optimized.The lower limits of quantifcation were in the range of 0.05-5 ng mL^(−1) with wide linear range for the ten steroid hormones.The intra-day precision<11.1%and recovery of 84.5-120% with negligible matrix efect were achieved,where within the acceptance limits of the FDA guideline.Total HPLC-MS analysis time was 6 min.This method enables simultaneous quantifcation of steroids in human serum.It will be helpful for the serum steroid profling in order to understand various endocrinology diseases.
文摘Chlorophenols (2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol and 2,4, 6-trichlorophenol) may be presented in natural waters or drinking water as a result of disinfection processes involving chlorination, or as contaminants derived from domestic products, industrial operations and agricultural chemicals. A previous HPLC-UV method for determination of phenol and five chlorophenols in tap water using 4-fluoro-7-nitro-2,1,3-benzoxadiaole as a UV labeling reagent shows limited sensitivity. Here, we present an improved HPLC-fluorescence detection method for simultaneous determination of phenol and the above chlorophenols in tap water after pre-column derivatization with 3-chlorocarbonyl-6,7-dimethoxy-1-methyl-2(1H)-quino- xalinone (DMEQ-COCl), using a short, narrow column (50 × 2.1 mm i.d., packed with 5 μm particles of C18 material) to improve the sensitivity. Standard samples containing the compounds are derivatized with DMEQ-COCl in borate buffer (pH 9.0) at room temperature for 3 mins. The response is linear in the concentration range of 0.01 - 0.05 to 0.5 mg/L with r2 values ≥0.9967 for all compounds. The lower limits of detection are 0.001 to 0.008 mg/L, and the coefficients of variation are less than 8.8%. The recovery values from tap water spiked with standard samples are satisfactory. The present method is suitable for examining whether or not tap water samples are contaminated with phenol and chlorophenols in excess of regulatory values.
文摘A convenient hydride derivatization procedure of methyl\|and ethylmercury chlorides to volatile hydrides was reported. In sealed vials methylmercury and ethylmercury compounds in acidic aqueous solutions were converted into their volatile forms by the reaction with potassium tetrahydroborate(KBH 4) and elvolved to the headspace of the vials. The gaseous analytes in the headspace were extracted and concentrated by solid phase microextraction(SPME) and injected into gas chromatography (GC) for separation and identified by mass selective detector(MS).
文摘Raspberry ketone {RK, 4-(4-hydroxyphenyl)butan-2-one} is a natural compound contained in raspberry, and is added to cosmetics for skin whitening. It is very important to measure the RK level in cosmetics for quality assessment, since RK structurally resembles 4-(4-hydroxyphenyl)-2-butanol, which causes leukoderma on consumers’ skin. Here, we present a simple HPLC-fluorescence method for determination of RK in a fragrance mist by pre-column derivatization with 4-hydrazino-7-nitro-2,1,3-benzoxadiazole hydrazine (NBD-H), which reacts with the carbonyl group of RK. The NBD-RK derivative was eluted from a reversed-phase ODS column, and detected with excitation at 470 nm and emission at 550 nm. The retention time of NBD-RK derivative obtained by reaction with NBD-H at 80°C for 20 min was 10.3 min. The standard curve was linear in the range of 0.2 to 10 μg/mL, with a correlation coefficient (r<sup>2</sup>) value of 0.9980. The lower limit of detection was 0.018 μg/mL (absolute amount of 1.8 pmol). The coefficients of variation were less than 8.1%. The content of RK in fragrance mist (1.00 mL) was 1.18 ± 0.07 mg (range: 1.12 to 1.28 mg, n = 5). Recovery tests were satisfactory (83.9% ± 3.9%;range: 79.6 to 88.8%, n = 5).
基金The National Nature Science Foundation of China(Grant Nos.20767004,21177163)111 Project B08044+1 种基金"985 Project"of Minzu University of China(MUC 98507-08)"211 Project"of Minzu University of China(MUC 02121103)
文摘A self-ordered ring(SOR) fluorescence microscopic imaging technique has been developed for the determination of trace amounts of sulfadiazine based on its derivatization with fluorescamine.In the presence of HAc-NaAc buffer solution(pH 3.12) and polyvinyl alcohol-124(PVA-124),the droplet containing fluorescamine derivatized sulfadiazine can form a SOR on the solid support after solvent evaporation with the diameter of 1.86mm and its ring belt width of 54.9 μ m.The quantitative analysis of sulfadiazine is achieved with the linear range of 7.8×10-14 ～1.8×10-12 mol·ring-1(3.9×10-7 ～9.0×10-6 mol·L-1) and detection limit of 7.8×10-15 mol·ring-1(3.9×10-8 mol·L-1) when 0.2 μ L droplet was spotted.The technique has been satisfactorily applied to the determination of sulfadiazine in the tablet,synthetic sample and residues in six different milk samples with the recoveries of 91.0%～105.8%,respectively,and RSDs less than 4.4%.
文摘A sensitive liquid chromatographic mcthod for the detection of andno acids with precolumn fluorescence derivatization with acridone-N-acetyl chloride has been developed. Andno acid derivatives were eluted in 4o ndn with good reproducibility. The reIative standard deviations (n=6) at an analytical concentration of 50 pmol are < 4%. The method described is also suitable for the analysis of andno acids in different biological samples.
基金supported by Science and Technology Development Fund, Macao SAR (File Nos.: 0052/2018/A2 and 0077/2019/ A2)the National Natural Science Foundation of China (Grant No.: 61827819)
文摘Endogenous ribonucleotides(RNs)and deoxyribonucleotides(dRNs)are important metabolites related to the pathogenesis of many diseases.In light of their physiological and pathological significances,a novel and sensitive pre-column derivatization method with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide(MTBSTFA)was developed to determine RNs and dRNs in human cells using high-performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).A one-step extraction of cells with 85%methanol followed by a simple derivatization reaction within 5 min at room temperature contributed to shortened analysis time.The derivatives of 22 nucleoside mono-,di-and tri-phosphates were retained on the typical C;column and eluted by ammonium acetate and acetonitrile in 9 min.Under these optimal conditions,good linearity was achieved in the tested calibration ranges.The lower limit of quantitation(LLOQ)was determined to be 0.1-0.4μM for the tested RNs and 0.001-0.1μM for dRNs.In addition,the precision(CV)was<15%and the RSD of stability was lower than 10.4%.Furthermore,this method was applied to quantify the endogenous nucleotides in human colorectal carcinoma cell lines HCT 116 exposed to 10-hydroxycamptothecin.In conclusion,our method has proven to be simple,rapid,sensitive,and reliable.It may be used for specific expanded studies on intracellular pharmacology in vitro.
基金supported by National Training Program of Innovation and Entrepreneurship for Undergraduates (202101341012)Talent Startup Project of Zhejiang A&F University Scientific Research and Development Fund (2034020154).
文摘Structural derivatization of natural products has been a continuing and irreplaceable source of novel drug leads.Natural phenols are a broad category of natural products with wide pharmacological activity and have offered plenty of clinical drugs.However,the structural complexity and wide variety of natural phenols leads to the difficulty of structural derivatization.Skeleton analysis indicated most types of natural phenols can be structured by the combina-tion and extension of three common fragments containing phenol,phenylpropanoid and benzoyl.Based on these fragments,the derivatization strategies of natural phenols were unified and comprehensively analyzed in this review.In addition to classical methods,advanced strategies with high selectivity,efficiency and practicality were empha-sized.Total synthesis strategies of typical fragments such as stilbenes,chalcones and flavonoids were also covered and analyzed as the supplementary for supporting the diversity-oriented derivatization of natural phenols.
文摘A rapid and reproducible method has been developed for the simultaneous quantification of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in rat brain microdialysates. Derivatization was processed through reductive amination with butyraldehyde and sodium cyanoborohydride at 60℃ for 80 min incubation. Dibutylated monoamine neurotransmitters (MANTs) were directly analyzed with ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The chromatographic run time was shorter (2.1 min/sample) than previous studies [15] [18] [20]. Good linearity (R2 > 0.99) was obtained for DA, NE and 5-HT in the range of 25 - 5000 pg/mL, 5 - 1000 pg/mL and 2.5 - 500 pg/mL, respectively. Acceptable precision (CV, 8.5% - 13.4%) as well as accuracy (recovery, 94.1% - 106.8%) could be acquired by analysis of six batches of quality control samples (QCs) at four different concentrations, which demonstrated the reliability and reproducibility of current method. This method was successfully applied to the simultaneous determination of DA, NE and 5-HT in rat brain microdialysates, where basal levels as well as elevated levels after dosing with amphetamine (AMPH) were quantified for all three MANTs. This study provides a simple and rapid way to analyze MANTs in the biofluid in the future.
文摘High performance liquid chromatography method for the separation of a series of chiral benzyl alcohols on N-(3,5-dinitrobenzoyl)-D-phenylglycine stationary phase (Macherey Nagel, Chiral-2) after pre-column achiral derivatization was developed. Cheap and easy available aromatic acid chlorides were used as derivatization agents. Good to excellent separations of the enantiomers were achieved in all cases in relatively short analytical runs. It was shown that the enantiorecognition depends on the substituents both in the starting alcohol and in the acid chloride. The method presents an efficient alternative to the direct analyses on polysaccharide and cyclodextrine-derived stationary phases.
文摘Use of new amphetamine-type stimulants (ATS) as designer drugs is a serious problem worldwide. ATS are used in tablet, capsule, and powder forms, and can be mixed with other drugs. There is little information available on how these new drugs are metabolized or their ability to inhibit the metabolism of co-administered drugs. This study aimed to investigate the metabolism of six 4-substituted analogs of methamphetamine (MA), and their potential inhibition of MA metabolism. The metabolism of MA and the 4-substituted MAs was examined in vitro using human metabolic enzymes. Metabolite analyses were performed using trifluoroacetyl derivatization and GC-MS. The experiments showed that cytochrome P450 2D6 (CYP2D6) was involved in the major metabolic pathway of MA, where it catalyzed N-demethylation of 4-fluoromethamphetamine (4-FMA), 4-chloromethamphetamine (4-CMA), 4-bromomethamphetamine (4-BMA), 4-iodomethamphetamine (4-IMA) and 4-nitromethamphetamine (4-NMA), and O-demethylation of 4-methoxymethamphetamine (4-MMA). The half maximal inhibitory concentration (IC50) values for CYP2D6 using MA as substrate were different for each of the 4-substituted MAs. The strongest inhibitors of amphetamine production from MA were, in order, 4-IMA, 4-BMA, 4-CMA, 4-MMA, 4-FMA, and 4-NMA. The same order was observed for the IC50 values for inhibition of p-hydroxymethamphetamine production from MA, except for the IC50 of 4-MMA. The IC50 values of 4-IMA were lower than the IC50 values of fluoxetine and higher than that of quinidine. The results of this study imply that the risk of illicit drug interactions fluctuates so widely that unintentional fatal drug poisonings could occur.
文摘This work aimed to study the derivatization unprecedented of glyphosate and AMPA solutions using N,O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) combined with trimethylchlorosilane (TMCS), evaluating the composition of the reaction medium, use of ultrasound, volume of BSTFA:pyridine and pH of the reaction medium. From this study it was inferred that the reaction medium was composed of BSTFA:pyridine in ratio 60:100, respectively, without ultrasonic vibration and pH adjustment that provide optimal conditions for analysis by GC-MS. Furthermore, the methodology used was simple and fast, and that was the most practical method commonly used.
文摘The purpose of this study is to develop an HPLC-UV (280 nm) method for simultaneous determination of phenol, five chlorophenols (2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, and 2,4,6-trichlorophenol), and three phenylphenols (2-phenylphenol, 3-phenylphenol, and 4-phenylphenol) in tap water after pre-column derivatization with 4-nitrobenzoyl chloride. Standard curves were obtained after derivatization with 4-nitrobenzoyl chloride in borate buffer (pH 8.5) at 50°C for 1 min. The nine 4-nitrobenzoyl derivatives were well separated in less than 15 min on a Cholester column. Calibration plots were linear in the range of 0.02 ~ 0.12 to 0.9 mg/L, with r2 values ≥0.9928, for all compounds. The lower limits of detection were 0.006 to 0.05 mg/L. The coefficients of variation were less than 12.0%. The recovery values from tap water spiked with a standard mixture of test compounds were satisfactory. While the levels of phenol, five chlorophenols, and three phenylphenols in tap water were below the lower limit of determination, our method is expected to be useful for monitoring and/or identifying environmental water samples that are contaminated with these compounds, i.e., for assessing compliance with the official guidelines of the World Health Organization.
文摘A highly sensitive HPLC method for the detection of amino acids and oligopeptides with 9-acridine formyl chloride by. pre-column fluorescence derivatization has been developed. Glycine. glycylglycine, histidine, triglycine and glutathione were separated on a reversed-phase C18 column with methanol-water-triethylamine eluent, derivatization and chromatographic conditions were optimized . The five derivatives were eluted in 28 min with a good reproducibility. Linear range of the calibration graph was 0.08-260 nmol/ml-1. The relative standard deviations(n=6) are < 5%. Detection limits (signal-to-noise ratio=3) for the five derivatives are 20-40
