共查询到20条相似文献,搜索用时 11 毫秒
1.
Summary The use of 2-(9-carbazole)ethyl chloroformate (CEOC) for pre-column derivatization of biogenic amines (BA) has been tested
for the first time. The reagent reacts completely with BA within 3 min at ambient temperature in acetonitrile solution to
form stable derivatives that are readily analyzed by reversed-phase HPLC. Study of the derivatization conditions revealed
derivatization yields to be excellent in borate buffer over the pH range 9.0–10.0. Maximum yields were obtained by use of
a three- to fourfold molar excess of reagent. The reaction is extremely tolerant of common buffer salts, no decrease in reaction
yield is discernible in well-buffered samples. The emission maximum for the CEOC-derivatives is 360 nm (λ
ex = 293 nm). All the derivatives fluoresced strongly and direct injection of the reaction mixture was possible, with no significant
disturbance from the major fluorescent reagent degradation by-products, 2-(9-carbazole)ethanol (CEOC-OH) and bis-(2-(9-carbazole)ethyl)
carbonate (CEOC)2. Separation of the derivatized BA by high-performance liquid chromatography with gradient elution was tested on a Hypersil
BDS C18 column. Excellent response linearity was observed over the concentration range from 0.25 to 94.6 μmol L−1 for the labeled BA. Detection limits were 117–840 fmol at a signal-to-noise ratio of 3∶1. Analysis of BA in a shrimp sauce
extract was conducted to demonstrate the applicability of the technique to real sample matrixes; results were satisfactory. 相似文献
2.
Mohammad Bagher Majnooni Bahareh Mohammadi Ronak Jalili Gholamreza Bahrami 《液相色谱法及相关技术杂志》2016,39(19-20):877-881
A new high-performance liquid chromatographic method is described for the determination of fatty acids in seed oils. The method was based on precolumn derivatization with 9-fluorenylmethyl chloroformate as a labeling agent and fluorescence detection. Fatty acids were extracted from the samples and subjected to derivatization with the reagent at 60°C for 10?min. The chromatographic separation of 14 fatty acids (C10–C22) was achieved on a combined loading compression octadecyl sulfate (CLC-ODS) column with a run time of 30?min. Three-step gradient elution of a mobile phase consisted of acetonitrile and water was used, and the signal was monitored at excitation and emission wavelengths of 265 and 315?nm, respectively. The method indicated favorable sensitivity and reproducibility for fatty acids’ derivatives. The detection limits, at a signal-to-noise ratio of 3, were 0.01–0.05?µg/ml and relative standard deviations (RSDs) were less than 0.27%. Excellent linear responses were observed with coefficients of 0.9995. This method was applied to quantify fatty acids in white, brown, and black sesame seeds’ oil. 相似文献
3.
A pre-column derivatization method for the sensitive determination of aldehydes using the tagging reagent 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl carbonylhydrazine (DBCEEC) followed by high-performance liquid chromatography with fluorescence detection and APCI-MS identification has been developed. The chromophore of fluoren-9-methoxy-carbonylhydrazine (Fmoc-hydrazine) reagent was replaced by 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl functional group, which resulted in a sensitive fluorescence tagging reagent DBCEEC. DBCEEC could easily and quickly labeled aldehydes. The maximum excitation (300 nm) and emission (400 nm) wavelengths did not essentially change for all the aldehyde derivatives. Derivatives were sufficiently stable to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z [M + (CH2)n]+ in positive-ion mode (M: molecular weight of DBCEEC, n: corresponding aldehyde carbon atom numbers). The collision-induced dissociation of protonated molecular ion formed fragment ions at m/z 294.6, m/z 338.6 and m/z 356.5. Studies on derivatization demonstrated excellent derivative yields in the presence of trichloroacetic acid (TCA) catalyst. Maximal yields close to 100% were observed with a 10 to 15-fold molar reagent excess. Separation of the derivatized aldehydes had been optimized on ZORBAX Eclipse XDB-C8 column with aqueous acetonitrile as mobile phase in conjunction with a binary gradient elution. Excellent linear responses were observed at the concentration range of 0.01-10 nmol mL−1 with coefficients of >0.9991. Detection limits obtained by the analysis of a derivatized standard containing 0.01 nmol mL−1 of each aldehyde, were from 0.2 to 1.78 nmol L−1 (at a signal-to-noise ratio of 3). 相似文献
4.
Summary A sensitive LC method for the detection of amino acids and oligopeptides with pre-column fluorescence derivatization has been
developed. Glycine, glycylglycine, triglycine, glutathione, glutamic acid, and cysteine were separated on a reversed-phase
C18 column with methanol-water-triethylamine eluent, derivatization and chromatographic conditions were optimized. The six derivatives
were eluted in 20 min with good reproducibility. The relative standard derviations (n=6) at an analytical concentration of
2×10−6 M are <5%. Detection limits (signal-to-noise ratio=3) for the six derivatives are 23–68 fmol. 相似文献
5.
A pre-column derivatization method for the sensitive determination of aldehydes using the tagging reagent 1,2-benzo-3,4-dihydrocarbazole-9-ethoxy-carbonylhydazine (BCEC) followed by high-performance liquid chromatography with fluorescence detection and enhance mass spectrometric identification has been developed. The chromophore of fluoren-9-methoxy-carbonylhydrazine (Fmoc-hydrazine) reagent was replaced by 1,2-benzo-3,4-dihydrocarbazole functional group, which resulted in a sensitive fluorescence derivatizing agent BCEC. BCEC can easily and quickly label aldehydes. The maximum excitation (333 nm) and emission (390 nm) wavelengths were essential no change for all the aldehyde derivatives. The fluorescence intensity was substantially affected by the solvents, being higher in organic than protic solvents. Derivatives are sufficiently stable to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z [M + (CH2)n − 1]+ (M: molecular mass of BCEC, n: corresponding aldehyde carbon atom numbers) under positive-ion mode. The collision-induced dissociation of protonated molecular ion formed products at m/z = 245.7.0, m/z = 263.7 and m/z = 217.7, and corresponding the cleavage of CH2OCO, CH2OCO and NCH2CH2 bonds, respectively. Studies on derivatization demonstrated excellent derivative yields in the presence of trichloroacetic acid (TCA) catalyst. Maximal yields close to 100% were observed with a 10- to 15-fold molar reagent excess. Separation of the derivatized aldehydes has been optimized on ZORBAX Eclipse XDB-C8 column with aqueous acetonitrile in conjunction with a binary gradient elution. Excellent linear responses were observed at the concentration range of 0.08-16.65 μmol/L with coefficients of >0.9999. Estimated detection limits for the aldehydes, obtained by successive dilution of a derivatized standard solution containing 16.65 μmol/L of each aldehyde (at a signal-to-noise ratio = 3:1), are from 3.75 to 16.65 fmol. 相似文献
6.
Sensitive determination of cinnarizine in human plasma by high performance liquid chromatography and fluorescence detection 总被引:2,自引:0,他引:2
Summary A sensitive high performance liquid chromatographic method has been developed for the determination of cinnarizine in human plasma. Cinnarizine and clocinizine (internal standard) were extracted from acidified plasma (pH 4.7) into carbon tetrachloride and the organic layer was evaporated. The products were separated on a Microspher C18 (3 m) column, using a mixture of 0.04 % triethylamine in 0.01 M ammonium dihydrogen phosphate (NH4H2PO4), pH adjusted to 4.2 with orthophosphoric acid (H3PO4), and acetonitrile (2080, v/v) as mobile phase, at a flow rate of 1 ml/min at 40°C. Fluorescence detection (ex = 245 nm, em = 310 nm) was used; the detection limit was 0.5 ng/ml under the conditions used, and the calibration curve linear in the concentration range evaluated (1–60 ng/ml). The assay has been used to measure cinnarizine concentrations in plasma after oral administration to volunteers. 相似文献
7.
Summary A high performance liquid chromatographic method for the determination of flecainide in serum has been developed. The analysis is performed on a microparticulate silica column. The eluate is monitored by fluorescence detection at an excitation wavelength of 300nm and an emission wavelength of 370nm. No sources of interference were identified and a coefficient of variation of less than 8% was observed on repeated flecainide determinations. The method has a good reproducibility, specificity and accuracy, and can be applied in therapeutic drug monitoring of flecainide in patients. 相似文献
8.
In this study, we developed a simple, rapid, sensitive, and reliable method for the determination of glucosamine sulfate in human plasma, which was based on derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) followed by reverse-phase HPLC-FLD. For the first time, FMOC-Cl was introduced into derivatization of glucosamine sulfate in human plasma. The amino groups of glucosamine sulfate and vertilmicin sulfate (the internal standard) were trapped with FMOC-Cl to form glucosamine-FMOC-Cl and vertilmicin-FMOC-Cl adducts, which can be very suitable for HPLC-FLD. Precipitation of plasma proteins by acetonitrile was followed by vortex mixing and centrifugation. Chromatographic separation was performed on a C18 column (DIAMONSIL 150 x 4 mm id, 5 microm) with a mobile phase gradient consisting of acetonitrile and water at a flow-rate of 1 mL/min. The retention times of glucosamine-FMOC-Cl and vertilmicin-FMOC-Cl adducts were 8.9 and 21.2 min, respectively. This method was shown to be selective and sensitive for glucosamine sulfate. The limit of detection was 15 ng/mL for glucosamine sulfate in plasma and the linear range was 0.1-10 mg/mL in plasma with a correlation coefficient (r) of 0.9999. The relative standard deviations (RSDs) of intra-day and inter-day assays were 5.2-8.1% and 6.1- 8.5%, respectively. Extraction recoveries of glucosamine sulfate in plasma were greater than 90%. The validated method was successfully applied to the determination of glucosamine sulfate in human plasma samples. 相似文献
9.
A method for the simultaneous determination of Nb and Ta in steel and alloy by reversed-phase high-performance liquid chromatography (RP-HPLC) was proposed. 2-(5-Bromo-2-pyridylazo)-5-diethylamino phenol (5-Br-PADAP) was used as a pre-column chelating agent to form a ternary complex with Nb(V) and Ta(V) and tartaric acid. The ternary complexes of Nb(V) and Ta(V) were eluted within 8 min on a C18 column with a mobile phase of methanol-water (55:45, v/v) containing 10 mmol l−1 acetate buffer (pH3.5) and determined with spectrophotometric detection at 598 nm. The detection limits for Nb(V) and Ta(V) were 0.60 and 0.72 μg l−1, respectively, when the ratio of signal-to-noise is 3. The proposed method was used to analyze Nb and Ta in cast iron, alloy and stainless steel. 相似文献
10.
L. Bengoechea T. Hernández C. Quesada B. Bartolomé I. Estrella C. Gómez-Cordovés 《Chromatographia》1995,41(5-6):94-98
Summary The present paper describes the development of a method for the differentiation of hydroxycinnamic acid derivatives by HPLC
with photodiode-array detection. Furthermore spectral data of the compounds under investigation are given. Whereas p-coumaric
acid derivatives are distinguishable from caffeic and ferulic acid derivatives by the positions of their spectrum maxima and
their convexity interval value, it is not possible to distinguish between caffeic and ferulic acid derivatives because of
overlapping spectrum maxima and convexity interval values. 相似文献
11.
F. Traoré G. A. Pianetti L. Dallery M. Tod J. Chalom R. Farinotti G. Mahuzier 《Chromatographia》1993,36(1):96-104
Summary Fluorogenic reagents (luminarin 3, luminarin 11 and luminarin 12), having a quinolizinocoumarin moiety as fluorophore and a carboxylic acid hydrazide function as reacting group, have been developed. These reagents were found to be highly sensitive fluorescence derivatization reagents for aldehydes and ketones in high-performance liquid chromatography. The reagents readily react with carbonyl compounds in aqueous sulphuric acid solution (0.1 M) at room temperature to produce the corresponding hydrazone derivatives, which can be separated on both reversed or normal-phase column. The structures of the derivatives were studied, together with their properties in reversed and normalphase chromatographic systems. UV absorbance, corrected fluorescence spectral data and quantum yields of luminarin 3, luminarin 11 and luminarin 12 are presented. The detection limits (signal to noise ratio=3) for aldehydes and ketones were in the sub-pmol range. Luminarin 3 was also applied to the determination of hydroxymethylfurfural (HMF) in orange juices and concentrates. The method for HMF involves the solid-liquid extraction of the juice by using a C-18 cartridge prior to derivatization and normal-phase separation of the derivative with fluorimetric detection at 387 nmex., 444 nm em. The calibration curve was linear for amounts of HMF ranging from 0.1 to 10 nmol. Intrarun relative standard deviation was 12.8% for 0.1 nmol and 2.6% for 1 nmol. Recovery studies indicated an average of 98.7±1.9% for juice concentrate and 99.8±3.2% for pasteurized juice. 相似文献
12.
Summary Acid hydrolysis (0.25M H2SO4) coupled with enzyme catalysis (pectolyase and β-D-glucuronidase) were employed to extract galacturonic and glucuronic acids
from microbial polysaccharides, plant residues, animal wastes, sewage sludge and soil. The glycuronic acids were separated
by high-performance anion chromatography (HPAC) on a strong anion-exchange column using 0.1M sodium hydroxide with 0.25M sodium acetate as the mobile phase and determined by pulsed amperometric detection (PAD). HPAC-PAD was found to be superior
to high-performance liquid chromatography with ultra-violet (UV) detection in terms of resolution and sensitivity of glycuronic
acids. HPAC-PAD was not subject to interferences present with low UV detection (210 nm) and was highly selective for glycuronic
acids. Enzymatic hydrolysis after treatment with mild acid (0.25M H2SO4) released galacturonic acids from orange peel and pectin, while glucuronic acid was released from Acacia powder. Large amounts
of glycuronic acids were also extracted from plant materials. Low levels of uronic acids were detected in poultry manure,
sewage sludge and organic-amended soils. 相似文献
13.
A pre-column derivatization method for the sensitive determination of amino acids and peptides using the tagging reagent 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC) followed by high-performance liquid chromatography with fluorescence detection has been developed. Identification of derivatives was carried out by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS/MS). The chromophore of 2-(9-carbazole)-ethyl chloroformate (CEOC) reagent was replaced by 1,2-benzo-3,4-dihydrocarbazole functional group, which resulted in a sensitive fluorescence derivatizing reagent BCEOC. BCEOC can easily and quickly label peptides and amino acids. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z (M + H)+ under electrospray ionization (ESI) positive-ion mode with an exception being Tyr detected at negative mode. The collision-induced dissociation of protonated molecular ion formed a product at m/z 246.2 corresponding to the cleavage of CO bond of BCEOC molecule. Studies on derivatization demonstrate excellent derivative yields over the pH 9.0-10.0. Maximal yields close to 100% are observed with a 3-4-fold molar reagent excess. Derivatives exhibit strong fluorescence and extracted derivatization solution with n-hexane/ethyl acetate (10:1, v/v) allows for the direct injection with no significant interference from the major fluorescent reagent degradation by-products, such as 1,2-benzo-3,4-dihydrocarbazole-9-ethanol (BDC-OH) (a major by-product), mono-1,2-benzo-3,4-dihydrocarbazole-9-ethyl carbonate (BCEOC-OH) and bis-(1,2-benzo-3,4-dihydrocarbazole-9-ethyl) carbonate (BCEOC)2. In addition, the detection responses for BCEOC derivatives are compared to those obtained with previously synthesized 2-(9-carbazole)-ethyl chloroformate (CEOC) in our laboratory. The ratios ACBCEOC/ACCEOC = 2.05-6.51 for fluorescence responses are observed (here, AC is relative fluorescence response). Separation of the derivatized peptides and amino acids had been optimized on Hypersil BDS C18 column. Detection limits were calculated from 1.0 pmol injection at a signal-to-noise ratio of 3, and were 6.3 (Lys)-177.6 (His) fmol. The mean interday accuracy ranged from 92 to 106% for fluorescence detection with mean %CV < 7.5. The mean interday precision for all standards was <10% of the expected concentration. Excellent linear responses were observed with coefficients of >0.9999. Good compositional data could be obtained from the analysis of derivatized protein hydrolysates containing as little as 50.5 ng of sample. Therefore, the facile BCEOC derivatization coupled with mass spectrometry allowed the development of a highly sensitive and specific method for the quantitative analysis of trace levels of amino acids and peptides from biological and natural environmental samples. 相似文献
14.
Summary The chiral reagent (−)-1-(9-fluorenyl)ethyl chloroformate (FLEC) has been evaluated for the enantioselective analysis of amphetamines
by liquid chromatography. For separation of the FLEC diastereomers conventional reversed-phase conditions were used. The conditions
affording the best enantiomeric resolution and sensitivity were determined for amphetamine, methamphetamine, ephedrine, pseudoephedrine,
3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxyethylamphetamine (MDE).
All the amphetamines assayed could be separated with resolution factors ranging from 0.91 to 1.92. Although FLEC is typically
used as a fluorogenic reagent, it was shown that UV detection is the best option for stereospecific analysis of the methylenedioxylated
amphetamine derivatives (MDA, MDMA, and MDE), because different fluorimetric responses were obtained for the corresponding
diastereomers. The utility of the proposed conditions for stereoselective analysis of amphetamines in different types of sample
is discussed. 相似文献
15.
A fluorimetric liquid chromatography for highly sensitive analysis of very long chain fatty acids as naphthoxyethyl derivatives 总被引:3,自引:0,他引:3
Summary A simple and sensitive liquid chromatographic method is described for the simultaneous determination of biologically important
very long chain fatty acids (docosanoic, tetracosanoic and hexacosanoic acids) as fluorogenic derivatives. The method is based
on the derivatization of the fatty acids with 2-(2-naphtoxy)ethyl 2-(piperidino)ethanesulfonate (NOEPES) in toluene in the
presence of potassium carbonate and 18-crown-6. Several parameters affecting the derivatization were studied, including reaction
temperature, reaction time, reaction solvent, base catalyst and the amount of the reagent. The resulting derivatives were
analyzed by HPLC with fluorimetric detection (λex=235 nm; λem=366 nm). The linear range for the determination of docosanoic,
tetracosanoic and hexacosanoic acids was 0.028–1.4 μM with a detection limit of about 5.6 nM (S/N=3) (56 fmol per 10 μL injection).
Application of the method to the analysis the non-esterified (free) very long chain fatty acids spiked in plasma proved feasible. 相似文献
16.
Hirofumi Inoue 《Analytica chimica acta》2004,511(2):267-271
A simple and highly sensitive high-performance liquid chromatography (HPLC) for the determination of pipecolic acid (PA) in serum was developed. Pipecolic acid and nipecotic acid (internal standard (IS)) were derivatised with 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride (DMS-Cl) to produce fluorescent sulfonamides. The labelling reaction was carried out at 70 °C for 15 min at pH 9.0. The fluorescent derivatives were separated on a reversed-phase column (45 °C) with a stepwise elution using methanol/acetonitrile/10 mmol l−1 acetic acid (42:5:53) and methanol at a flow rate of 1.0 ml/min and detected at excitation and emission wavelengths of 316 and 403 nm, respectively. The labelling yield was 100.8%. The detection limit of pipecolic acid was 4 fmol at signal-to-noise ratio of 3. The within-day and day-to-day relative standard deviations were 3.3-8.1 and 1.4-6.4%, respectively. The concentration of pipecolic acid in normal human serum was 1.09±0.37 μmol l−1. 相似文献
17.
高效液相色谱荧光测定及质谱鉴定分析血清中胆汁酸 总被引:1,自引:0,他引:1
利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙基苯磺酸酯(BDEBS)作柱前衍生化试剂,在EclipseXDB-C8色谱柱上,采用梯度洗脱对10种胆汁酸(BAs)荧光衍生物进行了优化分离。95℃下在二甲基亚砜(DMSO)溶剂中以柠檬酸钾作催化剂,衍生反应35min后获得稳定的荧光产物,衍生反应完全。荧光激发和发射波长分别为λex=333nm,λem=390nm。采用大气压化学电离源(APCISource)正离子模式,实现了血清中胆汁酸的定性测定。分析物的定量测定采用荧光法进行。线性回归系数均在0.9996以上,检出限为22.36~44.57×10-15mol。 相似文献
18.
A. López García E. Blanco González J. I. García Alonso A. Sanz-Medel 《Chromatographia》1992,33(5-6):225-230
Summary Analytical methods for the determination in environmental samples, of some selected Polycyclic Aromatic Hydrocarbons (PAH's), which are included on the EPA Priority Pollutant list, have been developed and evaluated. The methodology involves the extraction of PAH's from water samples by solvent extraction with dichloromethane. Solid samples were ultrasonically extracted with acetone/hexane and the extract was cleaned up on a silica gel/alumina column. The concentrated and cleaned up extracts were analysed by HPLC on a polymeric C18 column using a gradient of acetonitrile/water as the mobile phase and fluorescence detection. Typical detection limits lie in the range of 1–30 ng ml–1 of the analytes, but after sample pretreatment detection limits of 10–300 ng l–1 were obtained. The extraction, clean-up and HPLC methodology was applied to the determination of selected PAH's in coal washings samples and the method was validated by the quantification of PAH's in a natural contaminated and a spiked sediment. 相似文献
19.
A. J. Beysens G. H. Beuman J. J. van der Heijden K. E. J. Hoogtanders O. M. Steijger H. Lingeman 《Chromatographia》1994,39(7-8):490-496
Summary A sensitive and selective liquid chromatographic method, using precolumn derivatization with dansylhydrazine followed by fluorescence detection, has been developed for the determination of tacrolimus (FK 506) in whole blood. After haemolysis, whole blood samples are extracted with diethyl ether and derivatized. After on-line removal of excess dansylhydrazine on a C18 precolumn, the derivative is loaded on to a C18 clean-up column, and a heart cut is subsequently transferred to a graphitized carbon column, where the final separation takes place. The method requires 1 ml of sample and has a limit of quantitation of 3 ng/ml. At the 15 ng/ml level the precision isca 10%, and the response is linear from the limit of quantitation toca 200 ng/ml of FK 506 in whole blood. The capacity of the method is 50 samples/day and about 1000 1-ml samples can be analyzed without changing either clean-up or separation column. Finally, the applicability of the method for therapeutic drug monitoring is shown. 相似文献
20.
The chelator 2-[2-(5-bromoquinolinylazo)]-5-diethylaminophenol (5-Br-QADEAP) was synthesized. A method was developed for the
simultaneous determination of vanadium, niobium and tantalum as metal–5-Br-QADEAP chelates using rapid column high performance
liquid chromatography along with an on-line enrichment technique. Vanadium, niobium and tantalum were pre-column derivatized
with 5-Br-QADEAP to form colored chelates. The chelates were separated on a 4.6 × 10 mm, 1.8 μm rapid analytical column with
acetonitrile–water (50:50, v/v) containing pH 4.5 phosphate buffer and 0.01 mol L−1 of citrate as the mobile phase. The chelates were separated completely within 2.5 min. The detection limits (S/N = 3) of
vanadium, niobium and tantalum are 1.6, 1.6, and 1.8 ng L−1, respectively. This method was applied to the determination of vanadium, niobium and tantalum in alloy steel, water, and
geologic samples with good results. 相似文献