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1.
Evaluation of a novel ELISA for serotonin: urinary serotonin as a potential biomarker for depression
Nichkova MI Huisman H Wynveen PM Marc DT Olson KL Kellermann GH 《Analytical and bioanalytical chemistry》2012,402(4):1593-1600
Depression is a common disorder with physical and psychological manifestations often associated with low serotonin. Since
noninvasive diagnostic tools for depression are sparse, we evaluated the clinical utility of a novel ELISA for the measurement
of serotonin in urine from depressed subjects and from subjects under antidepressant therapy. We developed a competitive ELISA
for direct measurement of serotonin in derivatized urine samples. Assay performance was evaluated and applied to clinical
samples. The analytical range of the assay was from 6.7 to 425 μg serotonin/g creatinine (Cr). The limit of quantification
was 4.7 μg/g Cr. The average recovery for spiked urine samples was 104.4%. Average intra-assay variation was 4.4%, and inter-assay
variation was <20%. The serotonin analysis was very specific. No significant interferences were observed for 44 structurally
and nonstructurally related urinary substances. Very good correlation was observed between urinary serotonin levels measured
by ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS; ELISA = 1.16 × LC-MS/MS − 53.8; r = 0.965; mean % bias = 11%; n = 18). Serotonin was stable in acidified urine for 30 days at room temperature and at −20 °C. The established reference range
for serotonin was 54–366 μg/g Cr (n = 64). Serotonin levels detected in depressed patients (87.53 ± 4.89 μg/g Cr; n = 60) were significantly lower (p < 0.001) than in nondepressed subjects (153.38 ± 7.99 μg/g Cr). Urinary excretion of serotonin in depressed individuals significantly
increased after antidepressant treatment by 5-hydroxy-tryptophane and/or selective serotonin re-uptake inhibitor (p < 0.01). The present ELISA provides a convenient and robust method for monitoring urinary serotonin. It is suitable to monitor
serotonin imbalances and may be particularly helpful in evaluating antidepressant therapies. 相似文献
2.
Moriarty M Lee A O'Connell B Kelleher A Keeley H Furey A 《Analytical and bioanalytical chemistry》2011,401(8):2481-2493
Serotonin is a major neurotransmitter and affects various functions both in the brain and in the rest of the body. It has
been demonstrated that altered serotinergic function is implicated in various psychiatric disorders including depression and
schizophrenia. Serotonin has also been implicated along with dopamine in attention deficit–hyperkinetic disorder (AD-HKD).
This study provides a versatile validated method for the analysis of serotonin, hydroxyindole acetic acid and dopamine in
urine using LC-MS/MS. This method was then used to quantify these analytes in a test group of 17 children diagnosed with severe
AD-HKD. This group was compared to a matched control group to investigate the possibility that one of these compounds may
be a potential biomarker for this condition. The developed method provided good linear calibration curves for the multiplex
assay of analytes in urine (0.05–3.27 nmol/L; R
2 ≥ 0.9977). Acceptable inter-day repeatability was achieved for all analytes with RSD values (n = 9) ranging from 1.1% to 9.3% over a concentration range of 0.11–3.27 μmol/L in urine. Excellent limits of detection (LOD)
and limits of quantitation (LOQ) were achieved with LODs of 8.8–18.2 nmol/L and the LOQs of 29.4–55.7 nmol/L for analytes
in urine. Recoveries were in the ranges of 98–104%, 100–106% and 91–107% for serotonin, 5-HIAA and dopamine, respectively.
An appropriate sample clean-up procedure for urine was developed to ensure efficient recovery and reproducibility on analysis.
Evaluation of matrix effects was also carried out and the influence of ion suppression on analytical results reported. Confirmatory
analysis was carried out on a linear trap quadrupole-Orbitrap mass spectrometer to obtain high mass accuracy data of the target
analytes in the clinical samples. 相似文献
3.
Berthet A Bouchard M Schüpfer P Vernez D Danuser B Huynh CK 《Analytical and bioanalytical chemistry》2011,399(6):2243-2255
Captan and folpet are fungicides largely used in agriculture. They have similar chemical structures, except that folpet has
an aromatic ring unlike captan. Their half-lives in blood are very short, given that they are readily broken down to tetrahydrophthalimide
(THPI) and phthalimide (PI), respectively. Few authors measured these biomarkers in plasma or urine, and analysis was conducted
either by gas chromatography coupled to mass spectrometry or liquid chromatography with UV detection. The objective of this
study was thus to develop simple, sensitive and specific liquid chromatography–atmospheric pressure chemical ionization-tandem
mass spectrometry (LC/APCI-MS/MS) methods to quantify both THPI and PI in human plasma and urine. Briefly, deuterated THPI
was added as an internal standard and purification was performed by solid-phase extraction followed by LC/APCI-MS/MS analysis
in negative ion mode for both compounds. Validation of the methods was conducted using spiked blank plasma and urine samples
at concentrations ranging from 1 to 250 μg/L and 1 to 50 μg/L, respectively, along with samples of volunteers and workers
exposed to captan or folpet. The methods showed a good linearity (R
2 > 0.99), recovery (on average 90% for THPI and 75% for PI), intra- and inter-day precision (RSD, <15%) and accuracy (<20%),
and stability. The limit of detection was 0.58 μg/L in urine and 1.47 μg/L in plasma for THPI and 1.14 and 2.17 μg/L, respectively,
for PI. The described methods proved to be accurate and suitable to determine the toxicokinetics of both metabolites in human
plasma and urine. 相似文献
4.
M. Reska E. Ochsmann T. Kraus T. Schettgen 《Analytical and bioanalytical chemistry》2010,397(8):3563-3574
Styrene is one of the most important industrial chemicals, with an enormously high production volume worldwide. The urinary
mercapturic acids of its metabolite styrene-7,8-oxide, namely N-acetyl-S-(2-hydroxy-1-phenylethyl)-l-cysteine (PHEMA 1) and N-acetyl-S-(2-hydroxy-2-phenylethyl)-l-cysteine (PHEMA 2), are specific biomarkers for the determination of individual internal exposure to this highly reactive
intermediate of styrene. We have developed and validated a fast, specific and very sensitive method for the accurate determination
of the sum of phenylhydroxyethyl mercapturic acids (PHEMAs) in human urine with an automated multidimensional liquid chromatography–tandem
mass spectrometry method using 13C6-labelled PHEMAs as internal standards. Analytes were stripped from the urinary matrix by online extraction on a restricted
access material, transferred to the analytical column and subsequently determined by tandem mass spectrometry. The limit of
quantification (LOQ) for the sum of PHEMAs was 0.3 μg/L urine and allowed us to quantify the background exposure of the (smoking)
general population. Precision within series and between series ranged from 1.5 to 6.8% at three concentrations ranging from
3 to 30 μg/L urine; the mean accuracy was between 104 and 110%. We applied the method to spot urine samples from 40 subjects
of the general population with no known occupational exposure to styrene. The median levels (range) for the sum of PHEMAs
in urine of non-smokers (n = 22) were less than 0.3 μg/L (less than 0.3 to 1.1 μg/L), whereas in urine of smokers (n = 18), the median levels were 0.46 μg/L (less than 0.3 to 2.8 μg/L). Smokers showed a significantly higher excretion of the
sum of PHEMAs (p = 0.02). Owing to its automation and high sensitivity, our method is well suited for application in occupational or environmental
studies. 相似文献
5.
Jaisson S Gorisse L Pietrement C Gillery P 《Analytical and bioanalytical chemistry》2012,402(4):1635-1641
Homocitrulline (HCit), an amino acid formed by the carbamylation of ε-amino groups of lysine residues, is considered a promising
biomarker for monitoring diseases such as chronic renal failure and atherosclerosis. This paper describes a tandem mass spectrometric
method for total, protein-bound and free HCit measurement in plasma samples. HCit was separated from other plasma components
by hydrophilic interaction liquid chromatography. Detection was achieved by monitoring transitions of 190.1 > 127.1 and 190.1 > 173.1
for HCit, and 183.1 > 120.2 for d7-citrulline used as internal standard. This method allowed HCit quantification within 5.2 min and was precise (inter-assay
CV < 5.85%), accurate (mean recoveries ranging from 97% to 106%), and exhibited a good linearity from 10 nmol/L to 1.6 μmol/L.
Plasma samples from control and uremic mice (n = 10) were analyzed. In control mice, mean total plasma HCit concentration was 0.78 ± 0.12 μmol/mol amino acids, whereas
it was increased 2.7-fold in uremic mice plasma, reaching 2.10 ± 0.50 μmol/mol amino acids (p < 0.001). In conclusion, this method exhibits good analytical performances and meets the criteria of sensitivity suitable
for HCit concentration assessment in plasma samples. 相似文献
6.
Minakata K Nozawa H Gonmori K Yamagishi I Suzuki M Hasegawa K Watanabe K Suzuki O 《Analytical and bioanalytical chemistry》2011,400(7):1945-1951
An electrospray ionization tandem mass spectrometric (ESI-MS-MS) method has been developed for the determination of cyanide
(CN–) in blood. Five microliters of blood was hemolyzed with 50 μL of water, then 5 μL of 1 M tetramethylammonium hydroxide solution
was added to raise the pH of the hemolysate and to liberate CN– from methemoglobin. CN– was then reacted with NaAuCl4 to produce dicyanogold, Au(CN)2–, that was extracted with 75 μL of methyl isobutyl ketone. Ten microliters of the extract was injected directly into an ESI-MS-MS
instrument and quantification of CN– was performed by selected reaction monitoring of the product ion CN– at m/z 26, derived from the precursor ion Au(CN)2– at m/z 249. CN– could be measured in the quantification range of 2.60 to 260 μg/L with the limit of detection at 0.56 μg/L in blood. This
method was applied to the analysis of clinical samples and the concentrations of CN– in the blood were as follows: 7.13 ± 2.41 μg/L for six healthy non-smokers, 3.08 ± 1.12 μg/L for six CO gas victims, 730 ± 867 μg
for 21 house fire victims, and 3,030 ± 97 μg/L for a victim who ingested NaCN. The increase of CN– in the blood of a victim who ingested NaN3 was confirmed using MS-MS for the first time, and the concentrations of CN– in the blood, gastric content and urine were 78.5 ± 5.5, 11.8 ± 0.5, and 11.4 ± 0.8 μg/L, respectively. 相似文献
7.
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
8.
Shao-Wen Zhang Jun Xing Ling-Shuang Cai Cai-Ying Wu 《Analytical and bioanalytical chemistry》2009,395(2):479-487
Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) has been widely used as a biomarker of oxidative DNA damage. Measurements of
8-OHdG in urinary samples are challenging owing to the low level of 8-OHdG and the complex matrix. In this study, a novel
molecularly imprinted polymer (MIP) monolithic column was synthesized with guanosine as a dummy template which was used as
the medium for in-tube solid-phase microextraction (SPME). In-tube SPME coupled with HPLC/UV detection for extraction and
determination of urinary 8-OHdG was developed. The synthesized MIP monolithic column exhibited high extraction efficiency
owing to its greater phase ratio with convective mass transfer and inherent selectivity. The enrichment factor for 8-OHdG
was found to be 76 and the limits of detection and quantification of the method for urinary samples were 3.2 nmol/L (signal-to-noise
ratio 3) and 11 nmol/L (signal-to-noise ratio 10), respectively. The MIP’s selectivity also made the sample preparation procedure and chromatographic separation much easier. The linear range of the
proposed method was from 0.010 to 5.30 μmol/L (r = 0.9997), with a relative standard deviation of 1.1–6.8%, and the recovery for spiked urine samples was 84 ± 3%. The newly
developed method was successfully applied to determine urinary samples of healthy volunteers, coking plant workers, and cancer
patients. The 8-OHdG level in cancer patients was significantly higher than that in healthy people. 相似文献
9.
Hasegawa C Kumazawa T Uchigasaki S Lee XP Sato K Terada M Kurosaki K 《Analytical and bioanalytical chemistry》2011,401(7):2215-2223
Dextromethorphan was extracted from human plasma samples (100 μL) using MonoTip C18 tips, which are packed with C18-bonded monolithic silica gel that is attached to the inside of the tip. The samples, which contained dextromethorphan and
trimeprazine as an internal standard (IS), were mixed with 200 μL of distilled water and 50 μL of 1 mol/L glycine–sodium hydroxide
buffer (pH 10). The mixture was extracted to the C18 phase of the tip by 20 sequential aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the
C18 phase were then eluted with methanol by five sequential aspirating/dispensing cycles. The eluate was injected directly into
a gas chromatograph and detected by a mass spectrometer with selected ion monitoring in positive electron ionization mode.
An Equity-5 fused silica capillary column (30 m × 0.32 mm i.d., film thickness 0.5 μm) gave adequate separation of the dextromethorphan,
IS, and impurities. The recoveries of dextromethorphan and the IS spiked into plasma were >87.4%. The regression equation
for dextromethorphan showed excellent linearity from 2.5 to 320 ng/mL of plasma, and the limit of detection was 1.25 ng/mL
of plasma. The intraday and interday coefficients of variation were less than 10.5% and 14.7%, respectively. The accuracy
ranged from 91.9% to 107%. The validated method was successfully used to quantify the plasma concentration of dextromethorphan
in a human subject after oral administration of the drug. 相似文献
10.
Cahill MG Caprioli G Stack M Vittori S James KJ 《Analytical and bioanalytical chemistry》2011,400(2):587-594
Effluent from wastewater treatment plants have been identified as an important source of micro-organic contaminants in the
environment. An online high-performance liquid chromatography–heated electrospray ionization tandem mass spectrometric method
was developed and validated for the determination of basic pesticides in effluent wastewaters. Most available methods for
pesticide analysis of wastewater samples are time-consuming, require complex clean-up steps and are difficult to automate.
The method developed used a simple solid-phase extraction clean-up for salt and lipid reduction. On-line sample pre-concentration
was performed using a reversed phase (C18) column, and analytes were separated by back-flushing onto an analytical column (C8) with detection using QqQ MS. An option to increase MS resolution was exploited to minimize interference from endogenous
compounds in the matrix. A better than unit mass resolution was used (Q1 full width half maximum (FWHM) = 0.2 Da and Q3 FWHM = 0.7 Da),
which was as rugged as a unit resolution method, and improved signal/noise and better detection limits were achieved for the
targeted basic pesticides. This method was applied to the determination of 11 pesticides, including methoxytriazine, chlorotriazines,
chloroacetanilides, phenylurea and carbamate pesticides. The percentage recovery values for these pesticides using the online
trapping column were within the range, 73–95%, with relative standard deviation (RSD) values <8.9%. The highest concentrations
of these pesticides in wastewater effluents in County Cork, Ireland, were simazine (0.51 μg/L), prometon (0.14 μg/L), diuron
(0.21 μg/L) and atrazine (0.19 μg/L). 相似文献
11.
A weak cation-exchange monolithic column has been prepared in stainless steel tubing and used as the solid-phase extraction
material in quantitative analysis of caffeine and theophylline in urine. Column switching, with water as mobile phase, was
used for on-line cleaning and screening of human urine samples. Reversed-phase high-performance liquid chromatography was
then performed on a C18 column with methanol–water 30:70 (v/v) as mobile phase at a flow rate of 0.5 mL min−1. Ultraviolet detection was performed at 274 nm. Good linear relationships were obtained between response and concentrations
of caffeine and theophylline in the range 0.1–50 μg mL−1. Absolute recovery ranged from 77.4 to 82.3% and inter-day and intra-day relative standard deviations were less than 5%.
The method was suitable for analysis of caffeine and theophylline in human urine, because it eliminated tedious pretreatment
and enabled rapid, economic, repeatable, and effective assay of traces of the drugs in biological samples. 相似文献
12.
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
13.
Ana Fortuna Joana Sousa Gilberto Alves Amílcar Falcão Patrício Soares-da-Silva 《Analytical and bioanalytical chemistry》2010,397(4):1605-1615
For the first time, a simple, selective and accurate high-performance liquid chromatography method with ultraviolet detection
was developed and validated to quantify simultaneously three structurally related antiepileptic drugs; carbamazepine, oxcarbazepine,
and the recently launched eslicarbazepine acetate and their main metabolites, carbamazepine-10,11-epoxide, 10,11-trans-dihydroxy-10,11-dihydro-carbamazepine, and licarbazepine. The method involves a solid-phase extraction and a reverse-phase
C18 column with 5 cm length. The mobile phase consisting of water, methanol, and acetonitrile in the ratio 64:30:6 was selected
as the best one and pumped at 1 mL/min at 40 °C. The use of this recent column and an aqueous mobile phase instead of buffers
gives several advantages over the method herein developed; namely the fact that the chromatographic analysis takes only 9 min.
The method was validated according to the guidelines of the Food and Drug Administration, showing to be accurate (bias within
±12%), precise (coefficient variation <9%), selective and linear (r
2 > 0.997) over the concentration range of 0.05–30 μg/mL for carbamazepine; 0.05–20 μg/mL for oxcarbazepine; 0.15–4 μg/mL for
eslicarbazepine acetate; 0.1–30 μg/mL for carbamazepine-10,11-epoxide; 0.1–10 μg/mL for 10,11-trans-dihydroxy-10,11-dihydro-carbamazepine, and 0.1–60 μg/mL for licarbazepine. It was also shown that this method can adequately
be used for the therapeutic drug monitoring of the considered antiepileptic drugs, carbamazepine, oxcarbazepine, eslicarazepine
acetate, and their metabolites. 相似文献
14.
Ahn KC Gee SJ Kim HJ Aronov PA Vega H Krieger RI Hammock BD 《Analytical and bioanalytical chemistry》2011,401(4):1285-1293
Pyrethroid insecticides widely used in forestry, agricultural, industrial, and residential applications have potential for
human exposure. Short sample preparation time and sensitive, economical high-throughput assays are needed for biomonitoring
studies that analyze a large number of samples. An enzyme-linked immunosorbent assay (ELISA) was used for determining 3-phenoxybenzoic
acid (3-PBA), a general urinary biomarker of exposure to some pyrethroid insecticides. A mixed-mode solid-phase extraction
reduced interferences from acid hydrolyzed urine and gave 110 ± 6% recoveries from spiked samples. The method limit of quantification
was 2 μg/L. Urine samples were collected from forestry workers that harvest pine cone seeds where pyrethroid insecticides
were applied at ten different orchards. At least four samples for each worker were collected in a 1-week period. The 3-PBA
in workers classified as high, low, or no exposure based on job analysis over all sampling days was 6.40 ± 9.60 (n = 200), 5.27 ± 5.39 (n = 52), and 3.56 ± 2.64 ng/mL (n = 34), respectively. Pair-wise comparison of the differences in least squares means of 3-PBA concentrations among groups
only showed a significant difference between high and no exposure. Although this difference was not significant when 3-PBA
excretion was normalized by creatinine excretion, the general trend was still apparent. No significant differences were observed
among days or orchards. This ELISA method using a 96-well plate was performed as a high-throughput tool for analyzing around
300 urine samples measured in triplicate to provide data for workers exposure assessment. 相似文献
15.
Agricultural workers are exposed to folpet, but biomonitoring data are limited. Phthalimide (PI), phthalamic acid (PAA), and
phthalic acid (PA) are the ring metabolites of this fungicide according to animal studies, but they have not yet been measured
in human urine as metabolites of folpet, only PA as a metabolite of phthalates. The objective of this study was thus to develop
a reliable gas chromatography–tandem mass spectrometry (GC–MS) method to quantify the sum of PI, PAA, and PA ring-metabolites
of folpet in human urine. Briefly, the method consisted of adding p-methylhippuric acid as an internal standard, performing an acid hydrolysis at 100 °C to convert ring-metabolites into PA,
purifying samples by ethyl acetate extraction, and derivatizing with N,O-bis(trimethylsilyl)trifluoro acetamide prior to GC–MS analysis. The method had a detection limit of 60.2 nmol/L (10 ng/mL);
it was found to be accurate (mean recovery, 97%), precise (inter- and intra-day percentage relative standard deviations <13%),
and with a good linearity (R
2 > 0.98). Validation was conducted using unexposed peoples urine spiked at concentrations ranging from 4.0 to 16.1 μmol/L,
along with urine samples of volunteers dosed with folpet, and of exposed workers. The method proved to be (1) suitable and
accurate to determine the kinetic profile of PA equivalents in the urine of volunteers orally and dermally administered folpet
and (2) relevant for the biomonitoring of exposure in workers. 相似文献
16.
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
17.
Sheng-da Qi Shun-lian Tian Hong-xi Xu Joseph J. Y. Sung Zhao-xiang Bian 《Analytical and bioanalytical chemistry》2009,393(8):2059-2066
Serotonin (5-hydroxytryptamine, 5-HT) plays vital roles in regulating gastrointestinal functions. Thus, the detection of 5-HT
in the gastrointestinal tract is of great importance for biomedical research, medical diagnosis, and pharmaceutical therapy.
This paper presents a simple, sensitive, and fast method for the quantification of luminally released serotonin in the feces
and tissues of the rat proximal colon by means of capillary electrophoresis with laser-induced fluorescence detection. 5-Carboxyfluorescein
N-succinimidyl ester was used for precolumn derivatization of serotonin. The optimal separation and detection conditions were
obtained with an electrophoretic buffer containing 60 mM borate (pH 8.90) and an air-cooled argon-ion laser (excitation at
488 nm, emission at 520 nm). The serotonin concentrations in the feces and tissues of proximal colons were analyzed with this
method, and the average values of serotonin in the feces samples were 1.951 ± 0.446 ng/mg (male) and 2.095 ± 0.533 ng/mg (female)
and 1.397 ± 0.267 ng/mg in rat proximal colon tissues. The results demonstrate that this method can accurately determine luminally
released 5-HT in rats. 相似文献
18.
Rabagny Y Herrmann W Geisel J Kirsch SH Obeid R 《Analytical and bioanalytical chemistry》2011,401(3):891-899
We describe a fast and robust ultra performance liquid chromatography tandem mass spectrometry method for the quantification
of phospholipid (PL) species in EDTA-plasma samples. We quantified total phosphatidylcholine (PC), phosphatidylethanolamine
(PE), lysophosphatidylcholine (LPC), and sphingomyelin (SM) and several species within these classes using one or two external
calibrators and one internal standard for each class. Inter-assay coefficients of variation were <10% for the most abundant
species and <20% for all quantified PC, LPC, and SM species and the three most abundant PE species. Coefficients of linear
regression were R
2 > 0.98. Mean recoveries were between 83% and 123%. The limits of detection were 0.37 μmol/L for PC, 4.02 μmol/L for LPC,
3.75 μmol/L for PE, and 0.86 μmol/L for SM. Quantification was linear over the physiological ranges for PE, LPC, and SM and
up to 500 μmol/L for PC. The concentrations of PLs in the plasma of healthy donors yielded results that were comparable with
those of previous works. 相似文献
19.
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
20.
The opioid tilidine is a prodrug which is hepatically metabolized to active nortilidine and bisnortilidine. Due to the increasing
abuse of tilidine by drug users and the lack of a specific immunoassay, we developed an analytical method for the quantification
of tilidine, nortilidine, and bisnortilidine in urine suitable for screening. In a following step, this method was used to
establish data on excretion kinetics of the substances in order to evaluate the time window of detection after a single oral
dose of tilidine/naloxone and also was applied to authentic urine samples from correctional facilities. Urine samples were
mixed with internal standard solution and extracted on a weak cation exchanger at pH 6 using a Symbiosis Pico system. The
chromatographic separation was achieved within a 3.5-min run time on a Phenylhexyl column (50 × 2.0 mm, 5 μm) via gradient
elution (methanol and 0.2% formic acid) at a flow rate of 0.50 mL/min. The ESI-MS/MS was performed on a QTrap 3,200 in positive
multiple reaction monitoring mode using two mass transitions per analyte. Validating the method resulted in a lower limit
of quantification of 1.0 μg/L followed by a linear calibration range to 100 μg/L for each analyte (r
2 > 0.99). The analytical method allowed the detection of a single dose of a commercially available tilidine solution up to
7 days after administration. Using this highly sensitive method, 55 of 3,665 urine samples were tested positive. 相似文献