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1.
The analysis of four nitrofuran veterinary drugs, nitrofurantoin, furazolidone, furaltadone and nitrofurazone, was optimized
using reversed-phase liquid chromatography with a monolithic column and photo-diode array detection. The antibiotics were
extracted from animal feeds by heating with acetonitrile. The isocratic mobile phase consisted of a 8:92 (v/v) acetonitrile/phosphate buffer (pH 4.5) at a flow-rate of 1 mL min−1. Peaks were identified by the retention characteristics and UV spectra. Detection limits in the water samples ranged between
0.21 and 0.27 μg L−1, and in the feed samples between 2.1 and 2.7 μg kg−1, depending on the nitrofuran. The procedure was applied to the control of nitrofuran residues in farm water for poultry and
different animal feeds. 相似文献
2.
Analysis of abamectin residues in avocados by high-performance liquid chromatography with fluorescence detection 总被引:1,自引:0,他引:1
Hernández-Borges J Ravelo-Pérez LM Hernández-Suárez EM Carnero A Rodríguez-Delgado MA 《Journal of chromatography. A》2007,1165(1-2):52-57
In this work an analytical method for the determination of abamectin residues in avocados is developed using high-performance liquid chromatography (HPLC) with fluorescence (FL) detection. A pre-column derivatization with trifluoroacetic anhydride (TFAA) and N-methylimidazole (NMIM) was carried out. The mobile phase consisted of water, methanol and acetonitrile (5:47.5:47.5 v/v/v) and was pumped at a rate of 1 mL/min (isocratic elution). The fluorescence detector was set at an excitation wavelength of 365 nm and an emission wavelength of 470 nm. Homogenized avocado samples were extracted twice with acetonitrile:water 8:2 (v/v) and cleaned using C(18) solid-phase extraction (SPE) cartridges. Recovery values were in the range 87-98% with RSD values lower than 13%. The limits of detection (LODs) and quantification (LOQs) of the whole method were 0.001 and 0.003 mg/kg, respectively. These values are lower than the maximum residue limit (MRL) established by the European Union (EU) and the Spanish legislation in avocado samples. 相似文献
3.
A multiresidue method has been developed for the simultaneous determination of sulfadiazine, sulfathiazole, sulfapyridine,
sulfamerazine, sulfamethoxydiazine, sulfamethylthiazole, sulfamethazine, sulfamonomethoxine, sulfamethoxypyridazine, sulfisoxazole,
sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline in natural animal casings by HPLC after solid-phase extraction. The
sulfonamides were extracted with acetonitrile and the extract cleaned up with an Oasis MCX SPE cartridge prior to analysis.
Separation was on a ZOBAX Eclipse XDB-C8 column using gradient elution with acetonitrile/methanol/0.1% acetic acid. The effect of separation conditions on chromatographic
behavior and recovery has been studied. Calibration graphs were linear with very good correlation coefficients (r = 0.9983−0.9996) in the concentration range from 0.02 to 1 μg mL−1. The limits of quantitation (LOQ) for the 13 sulfonamides were in the range of 1.5–2.2 μg kg−1. Decision limits (CCα) and detection capabilities (CCβ) were in the range of 105.2–111.0 and 113.0–120.2 μg kg−1, respectively. The recovery for casings spiked with 1.5–100 μg kg−1 ranged from 65.2 to 85.9%. The relative standard deviations (RSDs) of the sulfonamides for six measurements at 100 μg kg−1 were from 2.2 to 7.7%. The applicability of the method to the analysis of salted swine casings, salted sheep casings and
dry casing samples was demonstrated. 相似文献
4.
Katrin M. Kirschbaum Susann Finger Friederike Vogel Rainer Burger Manfred Gerlach Peter Riederer Christoph Hiemke 《Chromatographia》2008,67(3-4):321-324
An automated high performance liquid chromatography with column-switching and ultraviolet detection was developed for the
analysis of risperidone and 9-hydroxyrisperidone. The method needs minimum sample preparation and is useful for the detection
down to a limit of 1 ng mL−1. Sample clean-up of serum was carried out on a CN 20 μm SPE-column using 8% (v/v) acetonitrile in water. Chromatographic separation was performed on ODS Hypersil C18 material with 38% (v/v) acetonitrile and 0.4% (v/v) TEMED in water. Application of the method to the analysis of serum samples confirmed its suitability for therapeutic drug
monitoring of risperidone and 9-hydroxyrisperidone. 相似文献
5.
IC Determination of Halide Impurities in Ionic Liquids 总被引:1,自引:0,他引:1
An ion chromatographic (IC) method has been developed for determination of trace levels of halide impurities in various types
of ionic liquids (ILs). The advantage of this method is that all relevant halide species can be measured in a single chromatographic
analysis. Separation of halides was performed on a Dionex AS9-HC column using an eluent consisting of 20 mM NaOH and 10% (v/v) acetonitrile, delivered at 1.5 mL min−1. Using this eluent, fluoride, chloride and bromide were well resolved from each other, but iodide was co-eluted with tetrafluoroborate
(BF4−) present as a counter-anion in tetrafluoroborate-based ILs. The same eluent was also used successfully for the determination
of halides in highly hydrophobic ILs, such as those based on bis-(trifluoromethanesulfonyl)imide (TFSI−) and bis-perfluoroethylsulfonylimide (BETI−). In this case, 50% (v/v) acetonitrile aqueous was needed to dissolve the sample before injection, and this did not adversely affect the separation.
Detection limits in the measured solution were 0.1, 0.2 and 1.0 ppm for chloride, bromide and iodide, respectively, by conductivity
detection, and 0.02 ppm for iodide by UV detection. 相似文献
6.
Comparison of adsorbents for on-line solid-phase extraction of polycyclic aromatic hydrocarbons before liquid chromatography with UV detection 总被引:1,自引:0,他引:1
Summary On-line solid-phase extraction (SPE) coupled with reversed-phase liquid chromatography and UV detection at 254 nm has been
used for the determination of trace-level polycyclic aromatic hydrocarbons (PAH) in soil extracts. Five commercially available
adsorbents (C8, C18, PLRP-S, PRP-1, and Bond-Elut Env) were evaluated. Results showed that recovery of the PAH decreased with increasing molecular
weight, because of their poorer solubility. Recovery of high-molecular-weight PAH was significantly improved by addition of
10% (v/v) acetonitrile to the sample before loading of the SPE adsorbent. PAH recovery ranged from 64.0 to 108% when a 50
mL sample spiked with 1 μg L−1 was applied to these adsorbents. Determination of PAH was possible with detection limits below 0.05 μg L−1, which corresponds to 0.2 μg kg−1 soil. The method was successfully used to determine PAH in soil extracts. 相似文献
7.
Solid-phase extraction was used to isolate sulfacetamide, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethoxypyridazine and sulfamethoxazole from honey. The optimized procedure used polymeric Abselut Nexus cartridges and the sulfonamides were separated, in the isocratic mode, on an Inertsil ODS-3 (250 × 4 mm I.D., 5 μm) column, using methanol-0.05 M acetate buffer (pH 3.6) (20:80 v/v) with 1% (v/v) of acetic acid, UV detection at 263 nm and a flow-rate of 1 mL min−1. Caffeine was used as internal standard. Average recoveries of the analytes from spiked honey ranged from 80 to 117% and the detection limits based on a spiked honey extract were 20–25 μg kg−1. 相似文献
8.
MSPD procedure for determining buprofezin,tetradifon, vinclozolin,and bifenthrin residues in propolis by gas chromatography–mass spectrometry 总被引:1,自引:0,他引:1
dos Santos TF Aquino A Dórea HS Navickiene S 《Analytical and bioanalytical chemistry》2008,390(5):1425-1430
A simple and effective extraction method based on matrix solid-phase dispersion (MSPD) was developed to determine bifenthrin,
buprofezin, tetradifon, and vinclozolin in propolis using gas chromatography–mass spectrometry in selected ion monitoring
mode (GC–MS, SIM). Different method conditions were evaluated, for example type of solid phase (C18, alumina, silica, and Florisil), the amount of solid phase and eluent (n-hexane, dichloromethane, dichloromethane–n-hexane (8:2 and 1:1, v/v) and dichloromethane–ethyl acetate (9:1, 8:2 and 7:3, v/v)). The best results were obtained using 0.5 g propolis, 1.0 g silica as dispersant sorbent, 1.0 g Florisil as clean-up sorbent,
and dichloromethane–ethyl acetate (9:1, v/v) as eluting solvent. The method was validated by analysis of propolis samples fortified at different concentration levels
(0.25 to 1.0 mg kg−1). Average recoveries (four replicates) ranged from 67% to 175% with relative standard deviation between 5.6% and 12.1%. Detection
and quantification limits ranged from 0.05 to 0.10 mg kg−1 and 0.15 to 0.25 mg kg−1 propolis, respectively. 相似文献
9.
Lakshmi N. Roy Rabindra N. Roy Cole E. Denton Sean R. LeNoue Curtis A. Himes Sarah J. Richards Ashley N. Simon Chandra N. Roy Vikram S. Somal 《Journal of solution chemistry》2006,35(4):551-566
The values of the second dissociation constant, pK
2, and related thermodynamic quantities of N-[tris(hydroxymethyl)methyl-3-amino]propanesulfonic acid (TAPS) have already been reported at 12 temperatures over the temperature range 5–55 ∘C, including 37 ∘C. This paper reports the results for the pH of five equimolal buffer solutions with compositions: (a) TAPS (0.03 mol⋅kg−1) + NaTAPS (0.03 mol⋅kg−1); (b) TAPS (0.04 mol⋅ kg−1) + NaTAPS (0.04 mol⋅kg−1); (c) TAPS (0.05 mol⋅kg−1) + NaTAPS (0.05 mol⋅kg−1); (d) TAPS (0.06 mol⋅kg−1) + NaTAPS (0.06 mol⋅kg−1); and (d) TAPS (0.08 mol⋅kg−1) + NaTAPS (0.08 mol⋅kg−1). The remaining eight buffer solutions consist of saline media of the ionic strength I = 0.16 mol⋅kg−1, matching closely to that of the physiological sample. The compositions are: (f) TAPS (0.04 mol-kg−1) + NaTAPS (0.02 mol-kg−1) + NaCl (0.14 mol⋅kg−1); (g) TAPS (0.05 mol⋅kg−1) + NaTAPS (0.04 mol⋅kg−1) + NaCl (0.12 mol⋅kg−1); (h) TAPS (0.6 mol⋅kg−1) + NaTAPS (0.04 mol⋅kg−1) + NaCl (0.12 mol⋅kg−1); (i) TAPS (0.08 mol⋅kg−1) + NaTAPS (0.06 mol⋅kg−1) + NaCl (0.10 mol⋅kg−1); (j) TAPS (0.04 mol⋅ kg−1) + NaTAPS (0.04 mol⋅kg−1) + NaCl (0.12 mol⋅kg−1); (k) TAPS (0.05 mol⋅kg−1) + NaTAPS (0.05 mol⋅kg−1) + NaCl (0.11 mol⋅kg−1); (l) TAPS (0.06 mol⋅kg−1) + NaTAPS (0.06 mol⋅kg−1) + NaCl (0.10 mol⋅kg−1); and (m) TAPS (0.08 mol⋅kg−1) + NaTAPS (0.08 mol⋅kg−1) + NaCl (0.08 mol⋅kg−1). These buffers are recommended as a pH standard for clinical measurements in the range of physiological application. Conventional pH values, designated as pH(s), for all 13 buffer solutions from 5 to 55 ∘C have been calculated. The operational pH values with liquid junction corrections, at 25 and 37 ∘C for buffer solutions, designated above as (b), (c), (d), (e), (j), (l), and (m); have been determined based on the difference in the values of the liquid junction potentials between the accepted phosphate standard and the buffer solutions under investigation. 相似文献
10.
Rabindra N. Roy Lakshmi N. Roy Shahaf Ashkenazi Joshua T. Wollen Craig D. Dunseth Michael S. Fuge Jared L. Durden Chandra N. Roy Hannah M. Hughes Brett T. Morris Kevin L. Cline 《Journal of solution chemistry》2009,38(4):449-458
The values of the second dissociation constant, pK
2, of N-(2-hydroxyethyl) piperazine-N′-2-ethanesulfonic acid (HEPES) have been reported at twelve temperatures over the temperature range 5 to 55 °C, including
37 °C. This paper reports the results for the pa
H of eight isotonic saline buffer solutions with an I=0.16 mol⋅kg−1 including compositions: (a) HEPES (0.01 mol⋅kg−1) + NaHEPES (0.01 mol⋅kg−1) + NaCl (0.15 mol⋅kg−1); (b) HEPES (0.02 mol⋅kg−1) + NaHEPES (0.02 mol⋅kg−1) + NaCl (0.14 mol⋅kg−1); (c) HEPES (0.03 mol⋅kg−1) + NaHEPES (0.03 mol⋅kg−1) + NaCl (0.13 mol⋅kg−1); (d) HEPES (0.04 mol⋅kg−1) + NaHEPES (0.04 mol⋅kg−1) + NaCl (0.12 mol⋅kg−1); (e) HEPES (0.05 mol⋅kg−1) + NaHEPES (0.05 mol⋅kg−1) + NaCl (0.11 mol⋅kg−1); (f) HEPES (0.06 mol⋅kg−1) + NaHEPES (0.06 mol⋅kg−1) + NaCl (0.10 mol⋅kg−1); (g) HEPES (0.07 mol⋅kg−1) + NaHEPES (0.07 mol⋅kg−1) + NaCl (0.09 mol⋅kg−1); and (h) HEPES (0.08 mol⋅kg−1) + NaHEPES (0.08 mol⋅kg−1) + NaCl (0.08 mol⋅kg−1). Conventional pa
H values, for all eight buffer solutions from 5 to 55 °C, have been calculated. The operational pH values with liquid junction
corrections, at 25 and 37 °C have been determined based on the NBS/NIST standard between the physiological phosphate standard
and four buffer solutions. These are recommended as pH standards for physiological fluids in the range of pH = 7.3 to 7.5
at I=0.16 mol⋅kg−1. 相似文献
11.
M. E-S. Metwally 《Chromatographia》1999,50(1-2):113-117
Summary A high performance liquid chromatographic method has been developed for the simultaneous determination of chlorpheniramine
maleate (CPM), methscoplamine nitrate (MSN) and phenylephrine hydrochloride (PEH) in sustained release capsules. The separation
was carried out on a reverse-phase CN-column with use of a mobile phase consisting of 70% (v/v) solution of acetonitrile in water containing 2% (v/v) acetic acid and 0.005M sodium 1-hepatane sulfonate at a flow rate of 2 mL min−1. The eluted peaks were detected at 262 nm. The method is sensitive, accurate and rapid and can be used in the routine analysis
of the mixture of the three compounds. 相似文献
12.
Consuelo Cháfer-Pericás Ángel Maquieira Rosa Puchades Javier Miralles Amelia Moreno 《Analytical and bioanalytical chemistry》2010,396(2):911-921
An indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed in plate to detect three sulfonamide residues
(sulfamerazine (SMR), sulfadimetoxine (SDM), and sulfadiazine (SDZ)) in gilthead sea bream (Sparus aurata) samples. Different extraction methodologies—using methanol/water 1:1 (v/v) + ethylene diamine tetraacetic acid (EDTA) 0.5% (m/v), acetonitrile, phosphate-buffered saline (PBS) 10 mmol L−1 pH 7 and acetate buffer 100 mmol L−1 pH 5—and cleanup steps, based on solid-phase extraction (C18, SCX, Si) or liquid extraction with hexane, were assayed. As optimum, a fast and simple method using acetonitrile was selected
to extract the sulfonamide residues from the edible muscle of fish. Due to matrix effects, a standard addition calibration
curve in fish extract is necessary for quantification purposes. Sulfonamide-free samples were spiked at different concentration
levels (between 30 and 90 ng g−1, 5–15 ng mL−1 in plate) and average recoveries (n = 8), ranging from 71% to 95%, 65% to 79%, and 72% to 95%, were obtained for SMR, SDM, and SDZ, respectively. The assay detection
limits for these antibiotics were lower than 100 μg kg−1 (maximum residue level established by the European Union). The accuracy was evaluated by spiking blank fish extracts at different
concentrations (10–40 ng mL−1, 5–20 ng mL−1 in plate), and the relative errors ranged between ±20%. Finally, in order to confirm the utility of the developed ELISA as
a screening methodology, fish samples from different supermarkets were analyzed, and results were compared with those obtained
by a validated high-performance liquid chromatography (HPLC) method. The correlation between the results obtained by both
ELISA and HPLC methods is satisfactory.
相似文献
13.
A new high-performance liquid chromatography assay was developed for the determination of minocycline in plasma and brain.
A solid–liquid extraction procedure was coupled with a reversed-phase HPLC system. The system requires a mobile phase consisting
of acetonitrile:water:perchloric acid (26:74:0.25, v/v/v) adjusted to pH 2.5 with 5 M sodium hydroxide for elution through a RP8 column (250 × 3.0 mm, i.d.) with UV detection set
at 350 nm. The method proved to be accurate, precise (RSD < 20%) and linear between 0.15–20 μg mL−1 in plasma and 1–20 μg mg−1 in brain. The method was successfully applied to a blood-brain barrier minocycline transport study. 相似文献
14.
Simplified liquid-chromatographic determination of residues of tetracycline antibiotics in eggs 总被引:2,自引:0,他引:2
N. Furusawa 《Chromatographia》2001,53(1-2):47-50
Summary A high-performance liquid chromatographic (HPLC) procedure is described for the identification and quantification of residues
of tetracycline antibiotics (TCA) (oxytetracycline, tetracycline, chlortetracycline, and doxycycline), in eggs. Spiked and
blank samples were prepared by homogenization with 1∶1 (v/v) acetonitrile-mixed Mcllvaine buffer and EDTA solution (pH 4.0) then centrifugal ultrafiltration. HPLC was performed on a
reversed-phase column with acetonitrile-5% (v/v) aqueous acetic acid, 35∶65 (v/v), as mobile phase and photo-diode array detection. Average recoveries (each drug spiked at 0.1, 0.2, 0.3, 0.5 and 1.0 μg
g−1) were >-77% with standard deviations (SD) between 1.5 and 3.5%. The inter-assay variabilities and theirSD were <3.4% and <0.7%, respectively, and intra-assay variability was between 2.0 and 3.9%. The limits of quantitation (LOQ) were 0.064 0.087, 0.121, and 0.131 μg g−1 for OTC, TC, CTC, and DC, respectively. The total time required for the analysis of one sample was less than 30 min. 相似文献
15.
Determination of tetracycline residues in soil by pressurized liquid extraction and liquid chromatography tandem mass spectrometry 总被引:2,自引:0,他引:2
Vicente Andreu Pablo Vazquez-Roig Cristina Blasco Yolanda Picó 《Analytical and bioanalytical chemistry》2009,394(5):1329-1339
An optimized extraction and cleanup method for the analysis of chlortetracycline (CTC), doxycycline (DC), oxytetracycline
(OTC) and tetracycline (TC) in soil is presented. Soil extraction in a pressurized liquid extraction system, followed by extract
clean up using solid-phase extraction (SPE) and tetracycline determination by liquid chromatography tandem mass spectrometry
(LC-MS/MS) provided appropriate efficiency and reproducibility. Different dispersing agents and solvents for soil extraction
and several SPE cartridges for cleanup were compared. The best extraction results were obtained using ethylenediamine tetraacetic
acid-treated sand as dispersing agent, and water at 70 °C. The most effective cleanup was obtained using Strata-XTM sorbent in combination with a strong anion exchange cartridge. Recoveries ranged from 71% to 96% and precision, as indicated
by the relative standard deviations, was within the range of 8–15%. The limits of quantification (LOQs) by using LC-MS/MS,
based on signal-to-noise ratio (S/N) of 10, ranged from 1 μg kg−1 for TC to 5 μg kg−1 for CTC. These results pointed out that this technique is appropriate to determine tetracyclines in soils. Analysis of 100
samples taken in the Valencian Community revealed that, in soil, up to 5 μg kg−1 CTC, 15 μg kg−1 OTC, 18 μg kg−1 TC, and 12 μg kg−1 DC could be detected. Detection of the analytes in several samples, which typify great part of the Spanish agricultural soils,
should be outlined as most important result of this study.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
16.
A high-performance liquid chromatography–UV method for determining DCJW concentration in rat plasma was developed. The method
described was applied to a pharmacokinetics study of intramuscular injection in rats. The plasma samples were deproteinized
with acetonitrile in a one-step extraction. The HPLC assay was carried out using a VP-ODS column and the mobile phase consisting
of acetonitrile–water (80:20, v/v) was used at a flow rate of 1.0 mL min−1 for the effective eluting DCJW. The detection of the analyte peak area was achieved by setting a UV detector at 314 nm with
no interfering plasma peak. The method was fully validated with the following validation parameters: linearity range 0.06–10 μg mL−1 (r > 0.999); absolute recoveries of DCJW were 97.44–103.46% from rat plasma; limit of quantification, 0.06 μg mL−1 and limit of detection, 0.02 μg mL−1. The method was further used to determine the concentration–time profiles of DCJW in the rat plasma following intramuscular
injection of DCJW solution at a dose of 1.2 mg kg−1. Maximum plasma concentration (C
max) and area under the plasma concentration–time curve (AUC) for DCJW were 140.20 ng mL−1 and 2405.28 ng h mL−1. 相似文献
17.
Beom Soo Shin Deok Ki Hong Jong Hwan Kwak John Kim Sun Dong Yoo 《Chromatographia》2008,67(3-4):231-235
A rapid and sensitive liquid chromatography-tandem mass spectrometry assay was developed for the determination of a novel
histone deacetylase inhibitor, cyclo{(2S)-2-amino-8-[(aminocarbonyl)hydrazono]decanoyl-1-l-tryptophyl-l-isoleucyl-(2R)-2-piperidinecarbonyl} (SD-2007), in rat serum. The mobile phase consisted of acetonitrile and ammonium formate
(10 mM) (85:15 v/v), and the flow rate was 0.25 mL min−1. Chromatographic separations were achieved by isocratic elution on a C18 column. Multiple reaction monitoring was based on the transition of m/z = 681.8 → 83.6 for SD-2007 and 372.1 → 176.1 for trazodone (internal standard). A linearity was observed over a concentration
range from 2 to 1,000 ng mL−1 (r
2 > 0.999), with the lower limit of quantification at 2 ng mL−1 with 100 μL of rat serum. The mean intra- and inter-day assay accuracy ranged from 98.5–109.7% to 95.2–102.7%, respectively,
and the mean intra- and inter-day precision was between 4.3–11.3% and 2.9–13.3%. The developed assay was applied to a pharmacokinetic
study of SD-2007 in rats after intravenous injection (dose 4 mg kg−1). 相似文献
18.
Viñas P López-García I Bravo-Bravo M Briceño M Hernández-Córdoba M 《Analytical and bioanalytical chemistry》2012,403(4):1059-1066
A miniaturized dispersive liquid–liquid microextraction (DLLME) procedure coupled to liquid chromatography (LC) with fluorimetric
detection was evaluated for the preconcentration and determination of thiamine (vitamin B1). Derivatization was carried out by chemical oxidation of thiamine with 5 × 10−5 M ferricyanide at pH 13 to form fluorescent thiochrome. For DLLME, 0.5 mL of acetonitrile (dispersing solvent) containing
90 μL of tetrachloroethane (extraction solvent) was rapidly injected into 10 mL of sample solution containing the derivatized
thiochrome and 24% (w/v) sodium chloride, thereby forming a cloudy solution. Phase separation was carried out by centrifugation, and a volume of
20 μL of the sedimented phase was submitted to LC. The mobile phase was a mixture of a 90% (v/v) 10 mM KH2PO4 (pH 7) solution and 10% (v/v) acetonitrile at 1 mL min−1. An amide-based stationary phase involving a ligand with amide groups and the endcapping of trimethylsilyl was used. Specificity,
linearity, precision, recovery, and sensitivity were satisfactory. Calibration graph was carried out by the standard additions
method and was linear between 1 and 10 ng mL−1. The detection limit was 0.09 ng mL−1. The selectivity of the method was judged from the absence of interfering peaks at the thiamine elution time for blank chromatograms
of unspiked samples. A relative standard deviation of 3.2% was obtained for a standard solution containing thiamine at 5 ng mL−1. The esters thiamine monophosphate and thiamine pyrophosphate can also be determined by submitting the sample to successive
acid and enzymatic treatments. The method was applied to the determination of thiamine in different foods such as beer, brewer’s
yeast, honey, and baby foods including infant formulas, fermented milk, cereals, and purees. For the analysis of solid samples,
a previous extraction step was applied based on an acid hydrolysis with trichloroacetic acid. The reliability of the procedure
was checked by analyzing a certified reference material, pig’s liver (CRM 487). The value obtained was 8.76 ± 0.2 μg g−1 thiamine, which is in excellent agreement with the certified value, 8.6 ± 1.1 μg g−1. 相似文献
19.
Ning Ma Wen-Ying Liu Huan-De Li Xin-Yu Jiang Bi-Kui Zhang Rong-Hua Zhu Feng Wang Wei Liu Xia Liu Da-Xiong Xiang 《Chromatographia》2007,66(3-4):251-255
(E)-3,5,4′-trimethoxystilbene (BTM-0512) is a resveratrol analog with a variety of pharmacological action, including anti-cancer
properties, anti-allergic activity, estrogenic activity, antiangiogenic activity, and vascular-targeting activity against
microtubule-destabilization. There is, however, no validated analytical method for quantification of (E)-3,5,4′-trimethoxystilbene in biological matrices, so pharmacokinetic data and suitable methods for determination of the
compound in plasma are currently lacking. A rapid and sensitive liquid chromatographic–mass spectrometric method for determination
of (E)-3,5,4′-trimethoxystilbene in rat plasma, using carbamazepine as internal standard, has been developed and validated. Plasma
samples were treated with acetonitrile to precipitate proteins. Samples were then analyzed by HPLC on a 250mm × 4.6 mm i.d.,
5-μm particle, C18 column with methanol–water, 80:20 (v/v), containing 10 mm ammonium acetate and 0.2% formic acid (pH 3.0), as mobile phase, delivered at 0.85 mL min−1. A single-quadrupole mass spectrometer with an electrospray interface operated in selected-ion monitoring mode was used to
detect [M + H]+ ions at m/z 271.3 for (E)-3,5,4′-trimethoxystilbene and m/z 237.5 for the internal standard. (E)-3,5,4′-trimethoxystilbene and the internal standard eluted as sharp, symmetrical peaks with retention times of 8.9 and 4 min,
respectively. Calibration plots for (E)-3,5,4′-trimethoxystilbene in rat plasma at concentrations ranging from 0.01 to 5.0 μg mL−1 were highly linear. Intra-day and inter-day precision, as RSD, was <12.9%, and accuracy was in the range 94.8–104.7%. The
limit of detection in plasma was 0.005 μg mL−1. The method was successfully used to determine the concentration of (E)-3,5,4′-trimethoxystilbene after oral administration of 86 mg kg−1 of the drug to Sprague–Dawley rats and can be used to investigate the pharmacokinetics of the compound. 相似文献
20.
Li C Wen D Zhang J Chen Z Cong W Rao Z Liu H 《Analytical and bioanalytical chemistry》2006,386(7-8):1985-1993
Metabolism of four tobacco-specific N-nitrosamines (TSNAs), N′-nitrosonornicotine (NNN), N′-nitrosoanatabine (NAT), N′-nitrosoanabasine (NAB), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) has been studied by solid-phase extraction
(SPE) and liquid chromatography–tandem mass spectrometry (LC–MS–MS). 4-(Methylnitrosamino)-4-(3-pyridyl)-1-butanol (iso-NNAL)
was used as internal standard. SPE and LC–MS–MS was found to be a rapid, simple, sensitive, and selective method for analysis
of TSNAs in rabbit serum. The relative standard deviation (R.S.D., n = 6) for analysis of 5 ng mL−1 and 0.5 ng mL−1 standards and of serum sample spiked with 5 ng mL−1 standards of five TSNAs was 2.1–11% and recovery of 5 ng mL−1 standards from serum was 100.2–112.9%. A good linear relationship was obtained between peak area ratio and concentration
in the range of 0.2–100 ng mL−1 for NNAL and 0.5–100 ng mL−1 for other four TSNAs, with correlation coefficients (R
2) >0.99 (both linear and log–log regression). Detection limits for standards in solvent were between 0.04 and 0.10 ng mL−1. Doses of TSNAs administered to rabbits via the auricular vein were 4.67 μg kg−1 and 11.67 μg kg−1, in accordance with the different levels in cigarettes. Metabolic curves were obtained for the four TSNAs and for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol
(NNAL), a metabolite of NNK; on the basis of these curves we modeled metabolic kinetic equations for these TSNAs by nonlinear
curve fitting. 相似文献