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1.
A simple and sensitive assay was developed and validated for the simultaneous quantification of rosuvastatin acid (RST), rosuvastatin-5S-lactone (RST-LAC), and N-desmethyl rosuvastatin (DM-RST), in buffered human plasma using liquid chromatography–tandem mass spectrometry (LC-MS/MS).
All the three analytes and the corresponding deuterium-labeled (d6) internal standards were extracted from 50 μL of buffered
human plasma by protein precipitation. The analytes were chromatographically separated using a Zorbax-SB Phenyl column (2.1 mm × 100 mm,
3.5 μm). The mobile phase comprised of a gradient mixture of 0.1% v/v glacial acetic acid in 10% v/v methanol in water (solvent A) and 40% v/v methanol in acetonitrile (solvent B). The analytes were separated at baseline within 6.0 min using a flow rate of 0.35 mL/min.
Mass spectrometry detection was carried out in positive electrospray ionization mode. The calibration curves for all three
analytes were linear (R ≥ 0.9964, n = 3) over the concentration range of 0.1–100 ng/mL for RST and RST-LAC, and 0.5–100 ng/mL for DM-RST. Mean extraction recoveries
ranged within 88.0–106%. Intra- and inter-run mean percent accuracy were within 91.8–111% and percent imprecision was ≤15%.
Stability studies revealed that all the analytes were stable in matrix during bench-top (6 h on ice–water slurry), at the
end of three successive freeze and thaw cycles and at −80°C for 1 month. The method was successfully applied in a clinical
study to determine the concentrations of RST and the lactone metabolite over 12-h post-dose in patients who received a single
dose of rosuvastatin. 相似文献
2.
Hua Wei Jun Wen Rui Xie Houwen Lin Guorong Fan Yutian Wu 《Analytical and bioanalytical chemistry》2009,395(5):1461-1469
A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, followed by a 96-well protein precipitation,
has been developed and fully validated for the determination of Phakellistatin 13 (PK13), a new cyclic heptapeptide isolated
from the sponge Phakellia fusca Thiele, in rat plasma. After protein precipitation of the plasma samples (50 μL) in a 96-well plate by methanol (200 μL)
containing the internal standard Pseudostellarin B (20 ng/mL), the plate was vortex mixed for 3 min. Following filtration
for 5 min, the filtrate was directly injected into the LC-MS/MS system. The analytes were separated on an XB-C18 analytical
column (5 μm, 50 mm × 4.6 mm i.d.) using an eluent of methanol–water (85:15, v/v) and detected by electrospray ionization mass spectrometry in the negative multiple reaction monitoring mode with a chromatographic
run time of 5.0 min. The method was sensitive with a lower limit of quantification (LLOQ) of 0.1 ng/mL, with good linearity
(r > 0.999) over the quantitation range of 0.1–5 ng/mL. The validation results demonstrated that this method was significantly
specific, accurate, precise, and was successfully applied in measuring levels of PK13 in rat plasma following intravenous
administration of 20, 50, and 100 μg/kg of peptide in rats, respectively, which was suitable for the preclinical pharmacokinetic
studies on PK13. 相似文献
3.
David Guillén Frederic Cofán Emilio Ros Olga Millán Montse Cofán Antoni Rimola Mercè Brunet 《Analytical and bioanalytical chemistry》2009,394(6):1687-1696
A rapid, sensitive, and specific method was developed and validated using liquid chromatography-tandem mass spectrometry for
the simultaneous quantitation of atorvastatin (ATV) and its major metabolite ortho-hydroxyatorvastatin (o-HATV) in human plasma. The sample preparation involved a liquid–liquid extraction without chlorinated solvents and an on-line
solid-phase extraction exploring the possibilities that anion exchange offers. The analytical method presented intraday and
day-to-day variation below 10%; intraday and day-to-day accuracy stood between 94% and 105%; the limit of quantification was
0.1 ng/mL for ATV and 0.5 ng/mL for o-HATV; and the recovery was above 75% for both molecules. This method was applied successfully to quantitate ATV and o-HATV concentrations in an unstudied renal transplant recipient cohort treated with an immunosuppressive regime of tacrolimus
and mycophenolic acid and a cohort of hypercholesterolemic patients included in the study as a control group. It can be used
to evaluate patient adherence, drug–drug interactions, and pharmacokinetic/pharmacodynamic relationships. The results in our
study showed that ATV and o-HATV levels in the renal transplant group were significantly increased (p < 0.001), compared to the hypercholesterolemic group. 相似文献
4.
Zhao J Han X Zhao X Wang C Li Q Chen X Bi K 《Analytical and bioanalytical chemistry》2011,401(1):289-296
A liquid chromatographic–mass spectrometric (LC–MS) method has been developed and validated for simultaneous determination
of dehydroevodiamine and limonin from Evodia rutaecarpa in rat plasma. After addition of the internal standard, domperidone, plasma samples were extracted by liquid–liquid extraction
with ethyl acetate and separated on an Apollo C18 column (250 mm × 4.6 mm, 5 μm), with methanol–0.01% formic acid water (60:40, v/v) as mobile phase, within a runtime of 12.0 min. The analytes were detected without interference in the selected ion monitoring
(SIM) mode with positive electrospray ionization. The linear range was 1.0–500 ng mL−1 for dehydroevodiamine and 2.0–1,000 ng mL−1 for limonin, with lower limits of quantitation of 1.0 and 2.0 ng mL−1, respectively. Intra-day and inter-day precision were within 6.0% and 10.9%, respectively, for both analytes, and the accuracy
(relative error, RE, %) was less than 4.8% and 6.5%, respectively. The validated method was successfully applied to a comparative
pharmacokinetic study of dehydroevodiamine and limonin in rat plasma after oral administration of dehydroevodiamine, limonin,
and an aqueous extract of Evodiae fructus. The results indicated there were obvious differences between the pharmacokinetic behavior after oral administration of an
aqueous extract of Evodiae fructus compared with single substances. 相似文献
5.
Clavijo CF Hoffman KL Thomas JJ Carvalho B Chu LF Drover DR Hammer GB Christians U Galinkin JL 《Analytical and bioanalytical chemistry》2011,400(3):715-728
Opioids such as morphine are the cornerstone of pain treatment. The challenge of measuring the concentrations of morphine
and its active metabolites in order to assess human pharmacokinetics and monitor therapeutic drugs in children requires assays
with high sensitivity in small blood volumes. We developed and validated a semi-automated LC-MS/MS assay for the simultaneous
quantification of morphine and its active metabolites morphine 3β-glucuronide (M3G) and morphine 6β-glucuronide (M6G) in human
plasma and in dried blood spots (DBS). Reconstitution in water (DBS only) and addition of a protein precipitation solution
containing the internal standards were the only manual steps. Morphine and its metabolites were separated on a Kinetex 2.6-μm
PFP analytical column using an acetonitrile/0.1% formic acid gradient. The analytes were detected in the positive multiple
reaction mode. In plasma, the assay had the following performance characteristics: range of reliable response of 0.25–1000 ng/mL
(r
2 > 0.99) for morphine, 1–1,000 ng/mL (r
2 > 0.99) for M3G, and 2.5–1,000 ng/mL for M6G. In DBS, the assay had a range of reliable response of 1–1,000 ng/mL (r
2 > 0.99) for morphine and M3G, and of 2.5–1,000 ng/mL for M6G. For inter-day accuracy and precision for morphine, M3G and
M6G were within 15% of the nominal values in both plasma and DBS. There was no carryover, ion suppression, or matrix interferences.
The assay fulfilled all predefined acceptance criteria, and its sensitivity using DBS samples was adequate for the measurement
of pediatric pharmacokinetic samples using a small blood of only 20–50 μL. 相似文献
6.
Carola W. N. Damen Hilde Rosing Jan H. M. Schellens Jos H. Beijnen 《Analytical and bioanalytical chemistry》2009,394(4):1171-1182
A sensitive, specific and efficient high-performance liquid chromatography-tandem mass spectrometry assay for the simultaneous
determination of vincristine and actinomycin-D in human dried blood spots is presented. Dried blood spots were punched out
of a collection paper with a 0.25-in.-diameter punch. The analytes were extracted from the punched-out disc using sonication
during 15 min in a mixture of acetonitrile–methanol–water (1:1:1, v/v/v) containing the internal standard vinorelbine. Twenty-microlitre volumes were injected onto the HPLC system. Separation was
achieved on a 50 × 2.1 mm ID Xbridge C18 column using elution with 1 mM ammonium acetate–acetonitrile (70:30, v/v) adjusted to pH 10.5 with ammonia and run in a gradient with methanol at a flow rate of 0.4 mL/min. HPLC run time was 6 min.
The assay quantifies vincristine from 1 to 100 ng/mL and actinomycine-D from 2 to 250 ng/mL using a blood sample obtained
by a simple finger prick. Validation results demonstrate that vincristine and actinomycin-D can be accurately and precisely
quantified in human dried blood spots with the presented method. The assay can now be used to support clinical pharmacologic
studies with vincristine and actinomycin-D. 相似文献
7.
Authors developed a simple, sensitive, selective, rapid, rugged, and reproducible liquid chromatography–tandem mass spectrometry
method for the quantification of eletriptan (EP) in human plasma using naratriptan (NP) as an internal standard (IS). Chromatographic
separation was performed on Ascentis Express C18, 50 × 4.6 mm, 2.7 μm column. Mobile phase was composed of 0.1% formic acid:
methanol (40:60 v/v), with 0.5 mL/min flow rate. Drug and IS were extracted by liquid–liquid extraction. EP and NP were detected with proton
adducts at m/z 383.2→84.3 and 336.2→97.8 in multiple reaction monitoring (MRM) positive mode, respectively. The method was validated with
the correlation coefficients of (r
2) ≥ 0.9963 over a linear concentration range of 0.5–250.0 ng/mL. This method demonstrated intra- and inter-day precision within
1.4–9.2% and 4.4–5.5% and accuracy within 96.8–103% and 98.5–99.8% for EP. This method is successfully applied in the bioequivalence
study of 24 human volunteers. 相似文献
8.
Lawrence Asamoah Adutwum Naoya Kishikawa Kaname Ohyama Shiro Harada Kenichiro Nakashima Naotaka Kuroda 《Analytical and bioanalytical chemistry》2010,398(2):823-829
A sensitive and selective high performance liquid chromatography-peroxyoxalate chemiluminescence (PO-CL) method has been developed
for the simultaneous determination of chlorpheniramine (CPA) and monodesmethyl chlorpheniramine (MDCPA) in human serum. The
method combines fluorescent labeling with 4-(4,5-diphenyl-1H-imidazole-2-yl)phenyl boronic acid using Suzuki coupling reaction with PO-CL detection. CPA and MDCPA were extracted from
human serum by liquid–liquid extraction with n-hexane. Excess labeling reagent, which interfered with trace level determination of analytes, was removed by solid-phase
extraction using a C18 cartridge. Separation of derivatives of both analytes was achieved isocratically on a silica column
with a mixture of acetonitrile and 60 mM imidazole-HNO3 buffer (pH 7.2; 85:15, v/v) containing 0.015% triethylamine. The proposed method exhibited a good linearity with a correlation coefficient of 0.999
for CPA and MDCPA within the concentration range of 0.5–100 ng/mL. The limits of detection (S/N = 3) were 0.14 and 0.16 ng/mL
for CPA and MDCPA, respectively. Using the proposed method, CPA could be selectively determined in human serum after oral
administration. 相似文献
9.
Apichai Santalad Supalax Srijaranai Rodjana Burakham Jeremy D. Glennon Richard L. Deming 《Analytical and bioanalytical chemistry》2009,394(5):1307-1317
A cloud-point extraction (CPE) method using Triton X-114 non-ionic surfactant was developed for the extraction and preconcentration
of carbamate insecticide residues (i.e., methomyl, propoxur, carbofuran, carbaryl, isoprocarb, and promecarb) in fruit samples.
The optimum conditions of CPE were 1.5% (w/v) Triton X-114, 7.0% (w/v) NaCl and 20 min equilibrated at 45 °C. The surfactant-rich phase was then analyzed by reversed-phase high-performance liquid
chromatography with ultraviolet detection at 270 nm, under gradient separation using methanol and 0.1% (v/v) acetic acid. Under the study conditions, six carbamate insecticides were successfully separated within 27 min. Good reproducibility
was obtained with the relative standard deviation of <3% for retention time and <9% for peak area. Limits of detection in
the studied fruit samples were in the range of 0.1–1.0 mg kg−1. No carbamate insecticides were detected in the studied fruit samples. The high recoveries of the spiked fruit samples were
obtained in the range 80.0–107%. The CPE method has been shown to be a potential useful methodology for the preconcentration
of the target analytes, with a preconcentration factor of 14. Moreover, the method is simple, has high sensitivity, consumes
much less solvent than traditional methods, and is environmental friendly. 相似文献
10.
Liu X Xu J Li Y Dong F Li J Song W Zheng Y 《Analytical and bioanalytical chemistry》2011,399(7):2539-2547
A sensitive and effective method for simultaneous determination of triazolopyrimidine sulfonamide herbicide residues in soil,
water, and wheat was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The four
herbicides (pyroxsulam, flumetsulam, metosulam, and diclosulam) were cleaned up with an off-line C18 SPE cartridge and detected
by tandem mass spectrometry using an electrospray ionization source in positive mode (ESI+). The determination of the target
compounds was achieved in <2.0 min. The limits of detection were below 1 μg kg−1, while the limits of quantification did not exceed 3 μg kg−1 in different matrices. Quantitation was determined from calibration curves of standards containing 0.05–100 μg L−1 with r
2 > 0.997. Recovery studies were conducted at three spiked levels (0.2, 1, and 5 μg kg−1 for water; 5, 10, and 100 μg kg−1 for soil and wheat). The overall average recoveries for this method in water, soil, wheat plants, and seeds at three levels
ranged from 75.4% to 106.0%, with relative standard deviations in the range of 2.1–12.5% (n = 5) for all analytes. 相似文献
11.
A liquid chromatography–mass spectrometry (LC-MS) method was developed and validated for the simultaneous determination of
alisol A and alisol A 24-acetate from Alisma orientale (Sam.) Juz. in rat plasma using diazepam as an internal standard. A 200-μl plasma sample was extracted by methyl tert-butyl ether and the separation was performed on Kromasil C18 column (150 × 4.6 mm, 5 μm) with the mobile phase of acetonitrile (containing 0.1% of formic acid)–water (73:27, v/v) at a flow rate of 0.8 ml/min in a run time of 10 min. The two analytes were monitored with positive electrospray ionization
by selected ion monitoring mode. The lower limit of quantitation for both alisol A and alisol A 24-acetate were 10 ng/ml.
The calibration curves were linear in the measured range 10–1,000 ng/ml for alisol A and 10–500 ng/ml for alisol A 24-acetate.
The mean extraction recoveries were above 74.7% for alisol A and above 72.4% for alisol A 24-acetate from biological matrixes.
The intra- and inter-day precision for all concentrations of quality controls was lower than 14.1% (RSD %) for each analyte.
The accuracy ranged from −12.3% to 9.8% (RE %) for alisol A, and −8.6% to 14.2% (RE %) for alisol A 24-acetate. The method
was successfully applied to the study on the pharmacokinetics of alisol A and alisol A 24-acetate in rat plasma. 相似文献
12.
Carpinteiro I Abuin B Ramil M Rodríguez I Cela R 《Analytical and bioanalytical chemistry》2012,402(7):2471-2478
An improved selectivity method for the simultaneous determination of four benzotriazoles (benzotriazole, 4-methylbenzotriazole,
5-methylbenzotriazole, and 5,6-dimethyl-1H-benzotriazole) and six benzothiazoles (benzothiazole, 2-hydroxybenzothiazole, 2-benzothiazolamine, mercaptobenzothiazole,
2-methylbenzothiazole, and 2-methylthiobenzothiazole) in aqueous matrices has been developed. Under optimal conditions, analytes
are concentrated using a MAX solid-phase extraction (SPE) cartridge, based on divinylbenzene-N-vinylpyrrolidone functionalized with quaternary amine groups, which allows reversed-phase interactions in combination with
ionic exchange. Selected compounds are recovered with methanol–acetone 7:3 (v/v) whereas acidic interferences remained attached to the sorbent, and as determined by liquid chromatography coupled to tandem
mass spectrometry (LC-MS/MS), LOQs for surface, urban and industrial wastewater are in the range of 0.002–0.29 ng/mL. Figures
of merit of the method revealed good precision (RSD% <12%), linearity (R
2 > 0.99) and accuracy (%R = 80–100%) for surface waters and effluents allowing direct external standard quantification. For more complex samples, such
as urban and industrial raw wastewater, either the standard addition method or pseudo-external standard calibration using
matrix matched standards are recommended. Analysis of different real samples, surface, urban wastewater and, for the first
time, metal industry wastewater, reflected concentrations up to 310 ng/mL. The methylbenzotriazole isomers ratio was also
determined. 相似文献
13.
High‐throughput salting‐out‐assisted liquid–liquid extraction for the simultaneous determination of atorvastatin,ortho‐hydroxyatorvastatin,and para‐hydroxyatorvastatin in human plasma using ultrafast liquid chromatography with tandem mass spectrometry
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Yong Yang Qiufang Xu Lei Zhou Dafang Zhong Xiaoyan Chen 《Journal of separation science》2015,38(6):1026-1034
A high‐throughput, specific, and rapid liquid chromatography with tandem mass spectrometry method was established and validated for the simultaneous determination of atorvastatin and its two major metabolites, ortho‐hydroxyatorvastatin and para‐hydroxyatorvastatin, in human plasma. A simple salting‐out‐assisted liquid–liquid extraction using acetonitrile and a mass‐spectrometry‐friendly salt, ammonium acetate, was employed to extract the analytes from human plasma. A recovery of more than 81% for all analytes was achieved in 1 min extraction time. Chromatographic separation was performed on a Kinetex XB C18 column utilizing a gradient elution starting with a 60% of water solution (1% formic acid), followed by increasing percentages of acetonitrile. Analytes were detected on a tandem mass spectrometer equipped with an electrospray ionization source that was operated in the positive mode, using the transitions of m/z 559.3 → m/z 440.2 for atorvastatin, and m/z 575.3 → m/z 440.2 for both ortho‐ and para‐hydroxyatorvastatin. Deuterium‐labeled compounds were used as the internal standards. The method was validated over the concentration ranges of 0.0200–15.0 ng/mL for atorvastatin and ortho‐hydroxyatorvastatin, and 0.0100–2.00 ng/mL for para‐hydroxyatorvastatin with acceptable accuracy and precision. It was then successfully applied in a bioequivalence study of atorvastatin. 相似文献
14.
Borges KB de Oliveira AR Barth T Jabor VA Pupo MT Bonato PS 《Analytical and bioanalytical chemistry》2011,399(2):915-925
The purpose of this study was the development and validation of an LC–MS–MS method for simultaneous analysis of ibuprofen
(IBP), 2-hydroxyibuprofen (2-OH-IBP) enantiomers, and carboxyibuprofen (COOH-IBP) stereoisomers in fungi culture medium, to
investigate the ability of some endophytic fungi to biotransform the chiral drug IBP into its metabolites. Resolution of IBP
and the stereoisomers of its main metabolites was achieved by use of a Chiralpak AS-H column (150 × 4.6 mm, 5 μm particle
size), column temperature 8 °C, and the mobile phase hexane–isopropanol–trifluoroacetic acid (95: 5: 0.1, v/v) at a flow rate of 1.2 mL min−1. Post-column infusion with 10 mmol L−1 ammonium acetate in methanol at a flow rate of 0.3 mL min−1 was performed to enhance MS detection (positive electrospray ionization). Liquid–liquid extraction was used for sample preparation
with hexane–ethyl acetate (1:1, v/v) as extraction solvent. Linearity was obtained in the range 0.1–20 μg mL−1 for IBP, 0.05–7.5 μg mL−1 for each 2-OH-IBP enantiomer, and 0.025–5.0 μg mL−1 for each COOH-IBP stereoisomer (r ≥ 0.99). The coefficients of variation and relative errors obtained in precision and accuracy studies (within-day and between-day)
were below 15%. The stability studies showed that the samples were stable (p > 0.05) during freeze and thaw cycles, short-term exposure to room temperature, storage at −20 °C, and biotransformation
conditions. Among the six fungi studied, only the strains Nigrospora sphaerica (SS67) and Chaetomium globosum (VR10) biotransformed IBP enantioselectively, with greater formation of the metabolite (+)-(S)-2-OH-IBP. Formation of the COOH-IBP stereoisomers, which involves hydroxylation at C3 and further oxidation to form the
carboxyl group, was not observed. 相似文献
15.
A high-performance liquid chromatographic method with triple-quadrupole mass spectrometry detection (LC-MS-MS) was developed
and validated for the first time for the simultaneous quantification of zopiclone and its metabolites in rat plasma samples.
The analytes were isolated from rat plasma by liquid–liquid extraction and separated using a chiral stationary phase based
on an amylose derivative, Chiralpak ADR-H column, and ethanol–methanol–acetonitrile (50:45:5, v/v/v) plus 0.025% diethylamine as the mobile phase, at a flow-rate of 1.0 mL min−1. Moclobemide was used as the internal standard. The developed method was linear over the concentration range of 7.5–500 ng mL−1. The mean absolute recoveries were 74.6 and 75.7; 61.6 and 56.9; 72.5, and 70.7 for zopiclone enantiomers, for N-desmethyl zopiclone enantiomers and for zopiclone-N-oxide enantiomers, respectively, and 75.9 for the internal standard. Precision and accuracy were within acceptable levels
of confidence (<15%). The method application in a pilot study of zopiclone kinetic disposition in rats showed that the levels
of (+)-(S)-zopiclone were always higher than those of (−)-R-zopiclone. Higher concentrations were also observed for (+)-(S)-N-desmethyl zopiclone and (+)-(S)-N-oxide zopiclone, confirming the stereoselective disposition of zopiclone. 相似文献
16.
Boroujerdi AF Lee PA DiTullio GR Janech MG Vied SB Bearden DW 《Analytical and bioanalytical chemistry》2012,403(3):777-784
In-line solid-phase extraction–capillary electrophoresis coupled with mass spectrometric detection (SPE–CE–MS) has been used
for determination of 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), codeine (COD), hydrocodeine (HCOD), and 6-acetylmorphine
(6AM) in urine. The preconcentration system consists of a small capillary filled with Oasis HLB sorbent and inserted into
the inlet section of the electrophoresis capillary. The SPE–CE–MS experimental conditions were optimized as follows: the sample
(adjusted to pH 6.0) was loaded at 930 mbar for 60 min, elution was performed with methanol at 50 mbar for 35 s, 60 mmol L−1 ammonium acetate at pH 3.8 was used as running buffer, the separation voltage was 30 kV, and the sheath liquid at a flow
rate of 5.0 μL min−1 was isopropanol–water 50:50 (v/v) containing 0.5% acetic acid. Analysis of urine samples spiked with the four drugs and diluted 1:1 (v/v) was studied in the linear range 0.08–10 ng mL−1. Detection limits (LODs) (S/N = 3) were between 0.013 and 0.210 ng mL−1. Repeatability (expressed as relative standard deviation) was below 7.2%. The method developed enables simple and effective
determination of these drugs of abuse in urine samples at the levels encountered in toxicology and doping. 相似文献
17.
Vitor RV Martins MC Figueiredo EC Martins I 《Analytical and bioanalytical chemistry》2011,400(7):2109-2117
A method constituted by molecularly imprinted solid-phase extraction (MISPE) with high-performance liquid chromatography coupled
to diode array detector (HPLC-DAD) was developed for cotinine analysis in saliva samples. For this purpose, the separation
was carried out with a C18 reversed-phase column at 20 °C. The mobile phase which was composed of a mixture of 09:91 (v/v) acetonitrile/phosphate buffer, pH 6.3, was delivered with isocratic flow rate at 1.4 mL min−1. Employing MISPE, the best conditions were achieved with 1.5 mL of saliva plus 1.5 mL of 0.1 mol L−1 of acetate buffer, pH 5.5, which were then passed through a cartridge previously conditioned with 2 mL acetonitrile, 2 mL
methanol, and 2 mL of 0.1 mol L−1 sodium acetate buffer, pH 5.5. The washing was carried out with 1 mL deionized water, 1 mL of 0.1 mol L−1 sodium hydroxide, and 1 mL hexane; finally; the cotinine elution was carried out with 3 mL methanol/water (97.5: 2.5, v/v). Linearity ranged from 30 to 500 ng mL−1 with r > 0.99. Intra-assay, interassay precision, and accuracy ranged from 3.1% to 10.1%, 5.2% to 15.9%, and 99.22% to 111.17%,
respectively. The detection and quantification limits were 10 and 30 ng mL−1, respectively. This investigation has provided a reliable method for routine cotinine determination in saliva, and it is
an important tool for monitoring cigarette smoke exposure in smokers. The method was applied in five smokers’ samples who
consumed around five to 20 cigarettes per day and the values of cotinine in saliva were from 66.7 to 316.16 ng mL−1. 相似文献
18.
A sensitive LC-MS/MS assay for quantification of total and free concentrations of R- and S-warfarin in plasma was required
to support clinical studies on warfarin enantiomers. Several ultrafiltration devices were evaluated for separation of free
warfarin from plasma proteins. The highest precision and lowest non-specific binding was obtained for Centrifree ultrafiltration
devices. R- and S-warfarin were extracted from plasma (total) and ultrafiltrate (free) by liquid–liquid extraction with methyl
tert-butyl ether using d6-warfarin as internal standard. Mean extraction recovery was 68 ± 4%. The enantiomers were separated on a Chirobiotic V column
with isocratic elution using 40% methanol and 0.03% acetic acid in water. Negative mode electrospray ionisation was used for
MS/MS detection, monitoring the ion transition m/z 307/161. Calibration curves (quadratic, weighted 1/x) were fitted over the range of 20–2,000 ng/ml (r
2 ≥ 0.995) in plasma and 0.5–20 ng/ml (r
2 ≥ 0.998) in ultrafiltrate. The lower limit of quantification for R- and S-warfarin was 0.5 ng/ml in ultrafiltrate. Intra-
and interday precision (% RSD) and bias were within 10% in all cases, and matrix effects were negligible. The assay was applied
successfully to analysis of samples from clinical studies. 相似文献
19.
Mazzucchelli I Rapetti M Fattore C Franco V Gatti G Perucca E 《Analytical and bioanalytical chemistry》2011,401(3):1013-1021
The development of a simple and rapid high-performance liquid chromatography (HPLC) method for the determination of the new
antiepileptic drug rufinamide (RFN) in human plasma and saliva is reported. Samples (250 μl) are alkalinized with ammonium
hydroxide (pH 9.25) and extracted with dichloromethane using metoclopramide as internal standard. Separation is achieved with
a Spherisorb silica column (250 × 4.6 mm i.d., 5 μm) at 30 °C using as mobile phase a solution of methanol/dichloromethane/n-hexane
10/25/65 (vol/vol/vol) mixed with 6 ml ammonium hydroxide. The instrument used was a Shimadzu LC-10Av chromatograph and flow
rate was 1.5 ml min-1, with a LaChrom L-7400 UV detector set at 230 nm. Calibration curves are linear [r
2 = 0.998 ± 0.002 for plasma (n = 10) and r
2 = 0.999 ± 0.001 for saliva (n = 9)] over the range of 0.25–20.0 μg ml-1, with a limit of quantification at 0.25 μg ml-1. Precision and accuracy are within current acceptability standards. The assay is suitable for pharmacokinetic studies in
humans and for therapeutic drug monitoring. 相似文献
20.
Chang-Ching Lin Chien-Wen Kuo Li-Heng Pao 《Analytical and bioanalytical chemistry》2010,398(2):857-865
The first liquid chromatography–tandem mass spectrometry method was developed and validated for the simultaneous quantification
of p-aminohippuric acid and inulin, both typical biomarkers of kidney function. 5-(Hydroxymethyl)furfural, generated from inulin
by acid and heat preparation, was used as an inulin substitute for the quantification. Acetaminophen was used as the internal
standard. Solid-phase extraction was carried out with 5% methanol as the washing solution to optimize the retention of the
analytes and to avoid obstruction of the orifice plate of the mass spectrometer caused by any unreacted inulin residue remaining
from the sample preparation process. Chromatography separation was performed on a Symmetry C18 column and a mobile phase composed of 2 mM ammonium formate and 0.1% formic acid in water (solvent A) and 2 mM ammonium formate
and 0.1% formic acid in acetonitrile (solvent B) (30:70, v/v). Detection was performed with a triple-quadrupole tandem mass
spectrometer using positive ion mode electrospray ionization in the multiple reaction monitoring mode. The selected transitions
were m/z 195.2 → 120.2, 127.1 → 109.1, and 152.1 → 110.0 for p-aminohippuric acid, inulin [measured as 5-(hydroxymethyl)furfural], and acetaminophen, respectively. The linearity ranged
from 10 to 140 μg/mL and from 100 to 1,400 μg/mL for p-aminohippurric acid and inulin (r > 0.99), respectively. The precisions and accuracies were all within 12 and 11% for the lower limit of quantification and
quality control samples, respectively. This application was proven to be reliable and accurate and was successfully applied
to a renal function study. 相似文献