共查询到20条相似文献,搜索用时 31 毫秒
1.
Häubl G Berthiller F Hametner C Rechthaler J Jaunecker G Freudenschuss M Krska R Schuhmacher R 《Analytical and bioanalytical chemistry》2007,389(3):931-940
In this paper, the structure and the identity of fully 13C-substituted T-2 toxin were confirmed using high-resolution mass spectrometry, 1H-NMR, 13C-NMR, tandem mass spectrometry and HPLC–DAD. The purity of this compound was estimated to be at least 98.8% according to
UV data. The isotopic distribution of (13C24) T-2 toxin indicated a total isotopic enrichment of 98.2 ± 1.0 atom% 13C, and the application of different MS measurement modes revealed the MS/MS fragmentation pattern of T-2 toxin. Furthermore,
a stable isotope dilution mass spectrometry method for the quantification of T-2 toxin was developed using (13C24) T-2 toxin as internal standard. The method was evaluated with and without conventional clean-up and validated for maize
and oats. Both cereals showed strong matrix enhancement effects, which could be compensated for through the application of
the isotope-substituted internal standard. 相似文献
2.
In this study, the development and validation of an analytical method for triptolide in whole blood using high-performance
liquid chromatography coupled with atmospheric-pressure chemical ionization ion trap tandem mass spectrometry (LC–APCI-IT-MS-MS)
is reported. This is the first report of the systematic development and validation of an LC–MS-MS method for the quantitation
of triptolide in human whole blood using prednisolone as an internal standard (IS). Prior to LC–MS-MS analysis, liquid–liquid
extraction with ethyl acetate was used to isolate them from the biological matrix. Validation parameters such as specificity/selectivity,
limit of quantitation (LOQ), linearity, precision, accuracy and stability are evaluated for this method. The calibration curve
was linear (r
2 = 0.9973) in the concentration range of 0.5–100.0 ng mL−1 in human whole blood with a lower limit of quantitation of 0.5 ng mL−1. Intra- and inter-day relative standard deviations (RSDs) were less than 8.6 and 11.7%, respectively. Extraction recoveries
of triptolide ranged from 81.5 to 88.1%. This assay can be used to determine trace triptolide in human whole blood. 相似文献
3.
Jie Sun Yan Liang Lin Xie An Kang Yuan Xie Wei-Dong Chen Hua Lv Guang-Ji Wang 《Chromatographia》2007,66(1-2):49-54
Olprinone is a phosphodiesterase (PDE)-3 inhibitor. This paper describes a simple, selective and sensitive method for the
quantification of olprinone in rat plasma using a liquid–liquid extraction procedure followed by liquid chromatography mass
spectrometric (LC–MS) analysis. The method had an advantage of high sensitivity. Analyses were conducted at a flow rate of
0.25 mL min−1 by a gradient elution. The detection utilized selected ion monitoring in the positive ion mode at m/z 251.0 and 344.0 for the protonated molecular ions of olprinone and the internal standard, respectively. The quantitation
limit for olprinone in rat plasma was 0.5 ng mL−1. The linearity was also excellent over the concentration range of 0.5–100 ng mL−1 of olprinone. The intra- and inter-day precision (relative standard deviation (RSD) %) was lower than 10%, and accuracy ranged
from 90 to 110%. This developed method was successfully applied to analysis of olprinone in biological fluids. 相似文献
4.
Simple and sensitive methods for the spectrophotometric determination of iron(III) in food, based on the formation of coloured
complexes of Fe(III) with Chromazurol S (CAS) in the presence of tetradecyltrimethylammonium bromide (TTA) or octadecyltrimethylammonium chloride (ODTA) and Triton X-100 (TX100), have been developed. Optimum pH and the concentrations of CAS, TTA, ODTA, and TX100 ensuring maximum
absorbance have been determined. For the Fe-CAS-TTA-TX100 system the molar absorptivity is 1.12 × 105 L/(mol cm) at 650 nm; for Fe-CAS-ODTA-TX100 it is 1.35 × 105 L/(mol cm) at 659.5 nm. Beer’s law was obeyed for iron concentration in the range 0.08–0.56 μg/mL for the complex Fe-CAS-TTA-TX100
and 0.08–0.64 μg/mL for Fe-CAS-ODTA-TX100. The influence of several interfering ions has been discussed. The stoichiometry
of the complexes was established by applying Job’s method. The more sensitive method, based on the Fe-CAS-ODTA-TX100 system,
has been applied to the determination of iron in cereals. To evaluate the accuracy of the elaborated method, the determined
content of Fe was compared to the declared value as well as to the result obtained by the reference ICP-OES method. 相似文献
5.
An approach for rapid quantitation of 5-hydroxymethylfurfural (HMF) in honey using planar chromatography is suggested for
the first time. In high-performance thin-layer chromatography (HPTLC) the migration time is approximately 5 min. Detection
is performed by absorbance measurement at 290 nm. Polynomial calibration in the matrix over a range of 1:80 showed correlation
coefficients, r, of ≥ 0.9997 for peak areas and ≥ 0.9996 for peak heights. Repeatability in the matrix confirmed the suitability of HPTLC–UV
for quantitation of HMF in honey. The relative standard deviation (RSD, %, n = 6) of HMF at 10 ng/band was 2.9% (peak height) and 5.2% (peak area); it was 0.6% and 1.0%, respectively, at 100 ng/band.
Other possible detection modes, for example fluorescence measurement after post-chromatographic derivatization and mass spectrometric
detection, were also evaluated and can coupling can be used as an additional tool when it is necessary to confirm the results
of prior quantitation by HPTLC–UV. The confirmation is provided by monitoring the HMF sodium adduct [M + Na]+ at m/z 149 followed by quantitation in TIC or SIM mode. Detection limits for HPTLC–UV, HPTLC–MS (TIC), and HPTLC–MS (SIM) were 0.8 ng/band,
4 ng/band, and 0.9 ng/band, respectively. If 12 μL honey solution was applied to an HPTLC plate, the respective detection
limits for HMF in honey corresponded to 0.6 mg kg−1. Thus, the developed method was highly suitable for quantitation of HMF in honey at the strictest regulated level of 15 mg kg−1. Comparison of HPTLC–UV detection with HPTLC–MS showed findings were comparable, with a mean deviation of 5.1 mg kg−1 for quantitation in SIM mode and 6.1 mg kg−1 for quantitation in TIC mode. The mean deviation of the HPTLC method compared with the HPLC method was 0.9 mg kg-1 HMF in honey. Re-evaluation of the same HPTLC plate after one month showed a deviation of 0.5 mg kg−1 HMF in honey. It was demonstrated that the proposed HPTLC method is an effective method for HMF quantitation in honey.
相似文献
6.
Summary A gas chromatographic method for the determination of residues of Fosfomycin in chicken muscle samples has been developed.
Muscle samples were homogenised with TRIS buffer, containing phenylphosphonic acid (as internal standard) and Fosfomycin using
a tissue homogenizer. Afterwards, the samples were ultrafiltered and the ultrafiltrate was evaporated to dryness. A silylation
reagent for derivatization was used in order to reconstitute the residue. The linear concentration range of application was
10–150 μgg−1, with a detection and quantitation limit of 3.11 and 10 μgg−1, respectively. The method was efficient with a mean recovery of 87.83% from spiked muscle. The results obtained show that
gas chromatography is a useful method for the determination of Fosfomycin residues in chicken muscle samples. 相似文献
7.
Veronica M. T. Lattanzio Michele Solfrizzo Angelo Visconti 《Analytical and bioanalytical chemistry》2009,395(5):1325-1334
The selective enzymatic deacetylation of T-2 toxin to give HT-2 toxin has been investigated in aqueous crude extracts of different
cereals and exploited to develop an analytical method for the determination of the sum of T-2 and HT-2 toxins. The method
has been validated for the analysis of total T-2 and HT-2 toxins in maize, wheat, and oats, showing recoveries from 72 to
97% for maize, from 67 to 84% for wheat, and from 61% to 87% for oats, at spiking levels of 20–400 μg/kg, with relative standard
deviation lower than 10%. Liquid chromatography-tandem mass spectrometry was used for quantitative toxin determination. The
potential biological role of this enzymatic conversion and its perspectives for application in the development of antibody-based
analytical techniques are discussed.
相似文献
8.
A. Phonchai B. Janchawee S. Prutipanlai S. Thainchaiwattana 《Journal of Analytical Chemistry》2010,65(9):951-959
A methodology for the determination of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and methamphetamine (MA) in seized tablets using gas chromatography with a flame ionization detector (GC-FID) is described. The chromatographic conditions, i.e. gas flow rates and temperatures for the column, injector and detector
were optimized. The optimum chromatographic conditions were as follows: a CP-SIL 24 CB WCOT fused silica capillary column
(30 m × 0.32 mm I.D., 0.25 μm film thickness), N2 carrier gas flowing at 2.6 mL/min, injector temperature at 290°C and detector temperature at 300°C. The oven temperature
was ramped from 80°C at a rate of 20°C/min to final temperature of 270°C (1 min). All analytes were well separated within
7 min with an analysis time of 10.5 min. Calibration curves were linear over the concentration ranges of 3.125–200 μg/mL for
MDMA and 6.25–200 μg/mL for MDA and MA (r > 0.990). The intra- and inter-day precisions for determining all analytes were 2.32–10.38% RSD and 1.15–9.77% RSD, respectively.
The intra- and inter-day accuracies ranged from −19.79 to +17.51% DEV and −6.84 to +5.2% DEV, respectively. The lower limits
of quantification (LLOQs) were 3.125 μg/mL for MDMA and 6.25 μg/mL for MDA and MA. All analytes were stable at room temperature during 24 h but significant
loss occurred after 2-month storage at −20°C. The method was shown to be useful for determining the purity of MDMA in seized
tablets. 相似文献
9.
The Becke3LYP functional of DFT theory was used to investigate molecular structure and sodium affinity of the systems CH3CO2Na (1), CH3–O–SO3Na (2), CH3–NH–SO3Na (3), saccharide_1Na2 (4), saccharide_2Na (5), saccharide_3Na3 (6), saccharide_4Na2 (7), and saccharide_5Na2 (8), respectively, which are models of N- and O-sulfate glycosaminoglycans. Interaction enthalpies, entropies and Gibbs energies of the sodium-coordinated systems in the
gas phase were determined with the B3LYP/6-311+G(d,p) and B3LYP/6-31+G(d) methods. The computed Gibbs energies, ΔG
o
, of model systems 1–3 are negative and span a rather broad energy interval (from −500 to −1,500 kJ mol−1). Gibbs interaction energies for sodium acetate, sodium sulfate and sodium sulfamate functions of the five saccharides, systems
4–8 are always lower than those values found for the model compounds 1–3. The ionization of sodium salts of saccharides studied in gas phase is in most cases connected with considerable conformational
rearrangement of the ionic species. This rearrangement causes an additional energetic stabilization of anionic species and
is connected with the substantial release of entropy. 相似文献
10.
A reversed phase liquid chromatographic (LC) method coupled with DAD (250 nm) has been developed and validated for simultaneous
quantification of six alkaloids, dehydroevodiamine (1), wuzhuyuamide-I (2), 5-hydroxyrutaecarpine (3), 14-formyldihydrorutaecarpine (4), evodiamine (5) and rutaecarpine (6), in 12 batches evodiae fructus [the dried, unripe fruits of Evodia rutaecarpa (Juss.) Benth. or E. rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang, E.
rutaecarpa (Juss.) Benth. var. bodinieri (Dode) Huang] as a traditional Chinese medicine. The method was carried out by a C18 column (250 × 4.6 mm) with a gradient mobile phase of methanol, acetonitrile, and phosphoric acid–triethylamine–buffer solution.
The contents of 1–6 in the evodiae fructus could easily be determined within 70 min. The experimental results were satisfactory for the intra-day
and inter-day precision and accuracy of the method for simultaneous determination. The linear calibration ranges of 1–6 were 40–1,000, 20–500, 1–100, 10–500, 40–1,000 and 80–1,000 μg mL−1. The recoveries of 1–6 were 97.43–103.73% with RSDs from 0.21 to 1.99%. The limits of detection for 1–6 were 2.0, 2.0, 0.1, 1.0, 5.0 and 5.0 μg mL−1, and the limits of quantification were 6.6, 6.6, 0.3, 3.3, 16.5 and 16.5 μg mL−1. The method was successfully applied to the quantification of six alkaloids in the evodiae fructus. 相似文献
11.
V. N. Emel’yanenko S. P. Verevkin E. N. Burakova G. N. Roganov M. K. Georgieva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(8):1271-1279
The enthalpies of formation of δ-hexanolactone and δ-nonanolactone were determined by combustion calorimetry. Conformational
analysis and quantum-chemical calculations of equilibrium structures, fundamental vibrations, moments of inertia, and total
energies were performed for δ-pentanolactone (I), δ-hexanolactone (II), and δ-nonanolactone (III) by the B3LYP/6-311G(d,p), B3LYP/6-311++G(d,p), and G3MP2 methods. The experimental IR spectra and calculated vibrational frequencies were used to suggest the assignment
of vibrational frequencies of stable conformations. The thermodynamic properties of I–III in the ideal gas state were determined over the temperature range 0–1500 K. A thermodynamic analysis of mutual isomerization
in the gas and liquid phases over the temperature range 298.15–900 K and liquid-phase polymerization of γ- and δ-pentanolactones
and 4-pentenoic acid over the temperature range 298.15–500 K was performed. 相似文献
12.
A. Ebrahimi S. M. Habibi Khorassani H. Delarami H. Esmaeeli 《Journal of computer-aided molecular design》2010,24(5):409-416
The substituent effects on the geometrical parameters and the individual hydrogen bond (HB) energies of base pairs such as
X–adenine–thymine (X–A–T), X–thymine–adenine (X–T–A), X–guanine–cytosine (X–G–C), and X–cytosine–guanine (X–C–G) have been studied by the quantum mechanical calculations at the B3LYP and MP2 levels with the 6–311++G(d,p) basis set. The
electron withdrawing (EW) substituents (F and NO2) increase the total binding energy (ΔE) of X–G–C derivatives and the electron donating (ED) substituent (CH3) decreases it when they are introduced in the 8 and 9 positions of G. The effects of substituents are reversed when they are located in the 1, 5, and 6 positions of C, with exception of CH3 in the 1 position and F in the 5 position, which in both cases the ΔE value decreases negligibly small. With minor exceptions (X=8–CH3, 8–F, and 9–NO2), both ED and EW substituents increase slightly the ΔE values of X–A–T derivatives. The individual HB energies (∆E
HBs) have been estimated using electron densities that calculated at the hydrogen bond critical points (HBCPs) by the atoms
in molecules (AIM) method. Most of changes of individual HBs are in consistent with the ED/EW nature of substituents and the
role of atoms entered H-bonding. The remarkable change is observed for NO2 substituted derivative in each case. 相似文献
13.
Summary A new, highly sensitive and selective gas chromatography method, using radiochemical detection (GC-DR) was developed for the
selective determination of3H-labelled deramciclane and its N-desmethyl metabolite in dog plasma. Inter-day accuracy and precision, as well as system
suitability of the GC-RD method was investigated during the method validation. The calibration curve was proved to be linear
(r=0.9986) in a wide concentration range (13–1000 ngeqv mL−1)
The lower limit of quantitation (LLOQ) was 13.7 ngeqv mL−1, and the limit of the detection (LOD) was 1 ngeqv mL−1.
Using this new GC-RD method, plasma levels of3H-labelled deramciclane and its metabolite were determined in dogs, after the administration of a single 10 mg kg−1 oral dose. Pharmacokinetic curves and the calculated pharmacokinetic parameters were compared to those obtained using a previously
elaborated gas chromatography-nitrogen selective detection method (GC-NPD) and to those obtained by measuring the plasma level
of total radioactivity (liquid scintillation counting, LSC). Pharmacokinetic curves and the calculated pharmacokinetic parameters
obtained with the two different gas chromatography detection methods (NPD and RD) showed good correlation. Comparison of these
results to those acquired by total radioactivity measurement demonstrated that deramciclane was intensively metabolised. Moreover,
the biological half-life (t
1
2/β
) of the unknown metabolites proved to be more than a magnitude longer than the half-life of the parent compound or that of
N-desmethyl metabolite.
Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997. 相似文献
14.
Summary A sensitive gas chromatographic method is described for the analysis of fosfomycin (FOS) in chicken plasma using phenylphosphonic
acid (PPA) as the internal standard. Plasma samples were ultrafiltered, and the ultrafiltrate was then evaporated to dryness.
The residue was reconstituted with a silylation reagent for the derivatization of FOS and PPA. The methodology involves the
use of a HP-5 capillary column and a flame ionisation detector (FID). The retention times of FOS and PPA were 4.63 and 8.68
minutes, respectively. Response was linear in the range of 1–150 μ mL−1. The detection and quantitation limits were 1 and 2.1 μ mL−1, respectively. Recovery was determined as 109% for FOS. The method was applied to the determination of FOS in chicken plasma
samples collected during pharmacokinetic studies. 相似文献
15.
Mahmure Ü. Özgür Güzin Alpdoğan Bürge Aşçi 《Monatshefte für Chemie / Chemical Monthly》2002,133(2):219-223
Summary. A simple and rapid derivative spectrophotometric assay procedure is described for the analysis of caffeine (1), acetaminophen (2), and propyphenazone (3) in tablet formulations. The concentration range of application is 5.0–25.0 μg·cm−3 for 2 and 3 and 1.0–5.0 μg·cm−3 for 1. The method involves the extraction of the drugs from tablets with 0.1 N H2SO4, filtration, appropriate dilution, and measurement of the fourth derivative absorbance values at zero crossing wavelengths
of 230.0, 263.2, and 256.6 nm for 1, 2, and 3. As a reference method, a reversed phase HPLC procedure was developed. Commercially available tablets were analyzed; statistical
comparison of the results with those obtained from the reference method showed good agreement. The derivative spectrophotometric
method has the advantage of being simple, rapid, inexpensive, and easy to perform.
Received April 18, 2001. Accepted (revised) June 5, 2001 相似文献
16.
Summary For improved determination of aromatic amines by gas chromatography and detection with an electron capture detector (GC-ECD)
a derivatization method based on the bromination of the aromatic ring in an acetic acid medium was developed. In general,
all free ortho and para-positions relative to the amino group undergo electrophilic substitution. Separation of at least 30
compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were studied and only
in 6 cases were no derivatives obtained. Quantitation limits determined from calibration data are 1.2–40 μg L−1 for a 100 mL sample and an injection volume of 1 μL. Previous experiments suggest that both sample and injection volume may
be increased to lower the quantitation limit. 相似文献
17.
The alkynylation of nitrones catalyzed by chiral zinc(II)-complexes was studied by means of the density functional theory
(DFT). All the intermediates and transition states were optimized completely at B3LYP/6-31G(d,p) level. Calculation results
confirm that this alkynylation of nitrones was endothermic and the total absorbed energy was about 14 kJ/mol. The formation
of the M5 complexes was the rate-determining step and the chirality-limiting step for this alkynylation. The transition states TS3-re involve a H(8)–O(2)–Zn(6)–C(9)–C(14)–N(13)–O(12) 7-membered ring, and thus the transition states TS3-si involve a Zn(6)–C(9)–C(14)–N(13)–O(12) 5-membered ring. The dominant reaction is the attack of nitrones from the re-surface of M4. The reactivity of anti-nitrones was stronger than that of syn-nitrones for zinc-catalyzed alkynylation of nitrones. The
dominant reaction channel was cata → TS1b → M1b → M2 → M3b → TS2b → M4b → TS3b1-anti-re → M5b1-anti-re → Pro-R. The dominant products predicted theoretically were of R-chirality, (2R)-N-hydroxy-N-methylpent-3-yn-2-amine.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
M. S. Chernov’yants N. V. Aleshina I. V. Burykin 《Journal of Analytical Chemistry》2011,66(3):280-284
A procedure was developed for the determination of the following thioamides based on thiazole, 1,3,4-thiadiazole, 1,2,4-triazole,
and tetrazole: 2-mercaptothiazole (I), 2-mercapto-1,3,4-thiadiazole (II), 2-mercapto-5-methyl-1,3,4-thiadiazole (III), 3-mercapto-1,2,4-triazole (IV), 3-mercapto-4-methyl-1,2,4-triazole (V), and 5-mercapto-1-methyltetrazole (VI). The determination was performed by reversed-phase HPLC on a column (150 × 4 mm) packed with Diaspher-110-C18 (5 μm) using
elution with an acetonitrile-acetate buffer solution (pH 4.70) mixture (5: 95). Detection was performed at the light absorption
maximums of compounds I (320 nm), II (305 nm), III (310 nm), IV (260 nm), V (254 nm), and VI (245 nm). The calibration graphs were linear over the following concentration ranges (μg/mL): 0.47–11.72 (I), 0.47–11.82 (II), 0.53–13.22 (III), 0.40–10.11 (IV), 0.46–11.52 (V), and 0.46–11.62 (VI). The limits of detection were 0.45, 0.43, 0.50, 0.37, 0.41, and 0.42 μg/mL for compounds I–VI, respectively. Conditions for the separation of a mixture of compounds I and III–V and for the quantitative determination of compounds I–VI by capillary zone electrophoresis (CZE) were optimized. CZE was performed on a quartz capillary of size 60 cm (effective length of 50 cm) × 75 μm at a voltage of
20 kV with a borate buffer solution (pH 9.18). The procedure allowed us to evaluate the concentrations of substances in the
ranges of 1.17–93.75 (I), 1.18–94.54 (II), 1.32–105.76 (III), 1.01–101.13 (IV) 1.15–115.16 (V), and 1.16–116.15 (VI) μg/mL with the detection limits of 1.10, 1.11, 1.20, 0.96, 1.01, and 1.02 μg/mL for compounds I–VI, respectively. 相似文献
19.
Bizzarri M Cavaliere C Foglia P Guarino C Samperi R Laganà A 《Analytical and bioanalytical chemistry》2008,391(5):1969-1976
A label-free absolute quantitation method based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
(MALDI-TOF MS) has been developed. This methodology was applied to mouse heart in order to quantify cardiac troponin T (cTnT),
which is considered to be a sensitive marker of heart damage. The cTnT was extracted, isolated by reversed-phase high-performance
liquid chromatography, digested, and analyzed by MALDI-TOF MS. The MS-based quantitation was performed using matrix-matched
calibration curves (due to a matrix effect) of two synthetic peptides, one cTnT-specific peptide and one internal standard
peptide, respectively. Recoveries at three spiking levels ranged from 87–96%, with relative standard deviations of below 10%.
The method detection limit and the method quantitation limit, expressed as the amount of cTnT for the amount of total sarcomeric
protein extract, were 0.03 mg g−1 and 0.15 mg g−1, respectively. This method appears to be accurate and generally suitable for improving absolute protein quantitation. 相似文献
20.
Passive sampling and stir bar sorptive extraction for the determination of endocrine-disrupting compounds in water by GC-MS 总被引:1,自引:0,他引:1
Emanuele Magi Marina Di Carro Camilla Liscio 《Analytical and bioanalytical chemistry》2010,397(3):1335-1345
A new method using the extraction and preconcentration capabilities of stir bar sorptive extraction, combined with high-resolution
gas chromatography and mass spectrometry, was developed for the determination of five selected endocrine-disrupting compounds
(4-n-nonylphenol, bisphenol A, estrone, 17β-estradiol, and 17α-ethinylestradiol) in water. In situ derivatization to transform
the phenolic compounds into lipophilic and volatile analytes was carried out with acetic anhydride. Two different methods
of headspace derivatization to further improve the chromatographic properties of 17β-estradiol and 17α-ethinylestradiol were
developed and compared. The optimized method provided good sensitivity (limits of quantitation 1.2–2.6 ng), repeatability
(relative standard deviation 2–9%), and reproducibility (relative standard deviation 10–17%). Passive sampling by means of
polar organic chemical integrative samplers was applied to monitor river waters used as supply sources for drinking water
treatment plants in the Liguria region of Italy. The analytes showed a different distribution at the three sites considered;
bisphenol A proved to be the most abundant, ranging from 185 to 459 ng per sampler. 相似文献