Determination Of Catecholamines Research Articles

Facile synthesis of boronic acid-functionalized magnetic metal-organic frameworks for selective extraction and quantification of catecholamines in rat plasma.

Precise determination of the endogenous catecholamines, dopamine (DA), epinephrine (E) and norepinephrine (NE) faces substantial challenges due to their low physiological concentrations in plasma. We synthesized, for the first time, a magnetic metal–organic framework (MIL-100) composite with boronic acid-functionalized pore-walls (denoted as MG@MIL-100-B composite) using a metal–ligand-fragment coassembly (MLFC) strategy. The composites were then applied as an effective magnetic solid-phase extraction (SPE) sorbent for determination of trace catecholamine concentrations in rat plasma through coupling with HPLC-MS/MS. The obtained nano-composites exhibited high magnetic responsivity, uniform mesopores, large specific surface area, and boronic acid-functionalized inner pore-walls. Catecholamines in rat plasma were extracted through interaction between the cis-diol structures and the boronic acid groups in the MG@MIL-100-B composites. Extraction conditions were optimized by studying SPE parameters including adsorption and desorption time, elution solvent type, pH conditions and adsorbent amount. With our approach, the detection limits (S/N = 3) were as low as 0.005 ng mL−1 for DA and E, and 0.02 ng mL−1 for NE. Intra- and inter-day precision ranged from 2.84–6.63% (n = 6) and 5.70–11.44% (n = 6), respectively. Recoveries from spiking experiments also showed satisfactory results of 94.40–109.51%. Finally, the MG@MIL-100-B composites were applied successfully to determine catecholamine concentrations in rat plasma.

Comparison of Single Culture and the Consortium of Growth-Promoting Rhizobacteria from Three Tomato (Lycopersicon esculentum Mill) Varieties

Pheochromocytoma may be responsible for various cardiac events including cardiac arrhythmias Authors report the case of a young child in whom pheochromocytoma was revealed by a junctional tachycardia The determination of urinary free catecholamines found a very high level of Noradrenaline and the abdominal CT showed a left hilar renal mass

P 47 Tick disorders in children and differential diagnosis with progressive diseases of the nervous system

Objective The study of features of tick disorders and differential diagnosis with progressive diseases of the nervous system. Background In the general population the prevalence of ticks is quite large and the statistics of different countries is 1–13%. There are two main theories of ticks: genetic determination and neurogenic stress on the background of residual-organic lesions of various structures of the extra pyramidal system. Methods We performed a neurological, neurochemical (determination of catecholamines in the urine), neuroimaging (MRI) and psychological examination of children (5–15 years) with chronic tic disorder. total number of 250 children were studied. Results On the basis of complex neuropsychiatric examination, changes of catecholamines; neuroimaging and follow-up of children with chronic tic disorder evaluated the efficacy of the treatment of chronic tic disorder in children and indications for drug therapy, developed criteria for early diagnostics of ticks in the debut of hereditary degenerative diseases. Conclusion we did set multifactor genesis of chronic tic disorder, resulting from organic brain damage in childhood and psychological characteristics of the child’s personality and its interaction with other people. At follow-up study we found that chronic tic disorder may be the initial manifestation of progressive diseases of the nervous system. The features of emotional-personal sphere of children with chronic tics and features of the interaction of the child with chronic tics within the family were identified. Thus, the primary tics can be considered typical of neuropsychiatric disorders. In MRI study any specific for chronic tic disorder changes were not found.

Deficits in temporal processing in mice prenatally exposed to Valproic Acid.

Temporal processing in the seconds-to-minutes range, known as interval timing, is a crucial cognitive function that requires activation of cortico-striatal circuits via dopaminergic-glutamatergic pathways. In humans, both children and adults with autism spectrum disorders (ASD) present alterations in their estimation of time intervals. At present, there are no records of interval timing studies in animal models of ASD. Hence, the objective of the present work was to evaluate interval timing in a mouse model of prenatal exposure to valproic acid (VPA) - a treatment used to induce human-like autistic features in rodent models. Animals were assessed for their ability to acquire timing responses in 15-s and 45-s peak-interval (PI) procedures. Our results indicate that both female and male mice prenatally exposed to VPA present decreased timing accuracy and precision compared to control groups, as well as deviations from the scalar property. Moreover, the observed timing deficits in male VPA mice were reversed after early social enrichment. Furthermore, catecholamine determination by HPLC-ED indicated significant differences in striatal dopaminergic, but not serotonergic, content in female and male VPA mice, consistent with previously identified alterations in dopamine metabolism in ASD. These deficits in temporal processing in a mouse model of autism complement previous results in humans, and provide a useful tool for further behavioral and pharmacological studies.

High-performance electrochemical sensor based on electrodeposited iron oxide nanoparticle: catecholamine as analytical probe

In this paper, we report the synthesis and electrocatalytic activity of electrodeposited Fe2O3 nanoparticles modified on a glassy carbon electrode as highly sensitive sensors for determination of catecholamines. Results showed that the Fe2O3 nanoparticles on a glassy carbon electrode exhibit excellent catalytic activity toward catecholamines oxidation, including levodopa, dopamine, and epinephrine, resulting in a marked lowering in the peak potential and considerable improvement of the peak current as compared to the electrochemical activity at the bare glassy carbon electrode. The electrochemical characterizations of catecholamines were performed using cyclic voltammetry, chronoamperometry, and differential pulse voltammetry techniques. The electrocatalytic currents increase linearly with the levodopa, dopamine, and epinephrine concentrations in the ranges of 0.0625–1000, 0.25–1500, and 0.125–1000 µM, respectively, and the detection limits (3σ) were 24 ± 2, 14 ± 2, and 12 ± 2 nM, respectively.

Determination of catecholamines and endogenous related compounds in rat brain tissue exploring their native fluorescence and liquid chromatography.

The profiling analysis of catecholamines and their metabolites in brain tissue offers a crucial key to understand their functions in the body and the opportunity to follow up neural diseases. A rapid and simple liquid chromatography-fluorescence detection (LC-FLD) method was developed and validated for simultaneously measuring several catecholamines and endogenous related compounds in the rat brain tissue samples. The target analytes measured in this bioanalytical assay were levodopa (L-DOPA), dopamine (DA), norepinephrine (NE), epinephrine (E), 3-O-methyldopa (3-O-MD), and homovanillic acid (HVA), being the 3,4-dihydroxybenzylamine (DHBA) used as internal standard (IS). The six analytes (L-DOPA, DA, NE, E, 3-O-MD and HVA) can be determined in a single chromatographic run of less than 12min, and all the compounds (analytes and IS) were detected using their native fluorescence and monitored at excitation/emission wavelengths of 279nm/320nm, respectively. The chromatographic and detection conditions were experimentally optimized and then several validation parameters (linearity, limits of quantification and detection, precision and accuracy, recovery, stability and selectivity) were examined. In accordance with the international guidelines of the Food and Drug Administration and European Medicines Agency the method described herein exhibited limits of quantification in the range of 2-25ngmL-1, linearity in wide concentration ranges (r2≥0.994), and acceptable precision (coefficient variation ≤8.76%) and accuracy (bias ±14.65%) levels. Since the bioanalytical procedure does not involve pre-purification or derivatization of the sample, the absolute recovery was found to be around 100%. Moreover, the developed LC-FLD method was successfully applied for the determination of the compounds of interest in tissue samples of different rat brain regions (cerebellum, amygdala, cortex, hippocampus, striatum, mesencephalon, medulla oblongata, substantia nigra and ventral tegmental area). Hence, this assay represents a valuable bioanalytical tool to support several pre(non)clinical studies in the broad field of neurosciences, requiring the quantitative analysis of these bioamines and their metabolites.

無麻酔・無拘束ラットにおける血中カテコールアミン測定に関する基礎的検討 (I)

無麻酔・無拘束ラットにおける血中カテコールアミン測定に関する基礎的検討 (I)

Determination of urine catecholamines and metanephrines by reversed-phase liquid chromatography-tandem mass spectrometry

The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma. The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection. Urine samples were prepared using Oasis weak-cation-exchange cartridges. The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min. Adrenaline, noradrenaline, dopamine, metanephrine, normetanephrine, and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring (MRM). No evidence of ion suppression was observed. The assay was linear up to 5μmol/L for adrenaline, 5μmol/L for noradrenaline, 6.1μmol/L for dopamine, 5.6μmol/L for metanephrine, and 34.6μmol/L for normetanephrine, with lower limits of quantification of 5, 5, 12, 6 and 7 nmol/L, respectively. The intra-day and inter-day precisions for all analytes ranged from 0.59% to 4.64% and 1.98% to 4.80%, respectively. External quality assurance samples were assayed and showed excellent agreement with the target values. This simple method provides an improved assay for determining urine catecholamines and metanephrines.

In situ derivatization-ultrasound-assisted dispersive liquid–liquid microextraction for the determination of neurotransmitters in Parkinson’s rat brain microdialysates by ultra high performance liquid chromatography-tandem mass spectrometry

Simultaneous monitoring of several neurotransmitters (NTs) linked to Parkinson’s disease (PD) has important scientific significance for PD related pathology, pharmacology and drug screening. A new simple, fast and sensitive analytical method, based on in situ derivatization-ultrasound-assisted dispersive liquid–liquid microextraction (in situ DUADLLME) in a single step, has been proposed for the quantitative determination of catecholamines and their biosynthesis precursors and metabolites in rat brain microdialysates. The method involved the rapid injection of the mixture of low toxic bromobenzene (extractant) and acetonitrile (dispersant), which containing commercial Lissamine rhodamine B sulfonyl chloride (LRSC) as derivatization reagent, into the aqueous phase of sample and buffer, and the following in situ DUADLLME procedure. After centrifugation, 50μL of the sedimented phase (bromobenzene) was directly injected for ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) detection in multiple reaction monitoring (MRM) mode. This interesting combination brought the advantages of speediness, simpleness, low matrix effects and high sensitivity in an effective way. Parameters of in situ DUADLLME and UHPLC–MS/MS conditions were all optimized in detail. The optimum conditions of in situ DUADLLME were found to be 30μL of microdialysates, 150μL of acetonitrile containing LRSC, 50μL of bromobenzene and 800μL of NaHCO3-Na2CO3 buffer (pH 10.5) for 3.0min at 37°C. Under the optimized conditions, good linearity was observed with LODs (S/N>3) and LOQs (S/N>10) of LRSC derivatized-NTs in the range of 0.002-0.004 and 0.007-0.015 nmol/L, respectively. It also brought good precision (3.2-12.8%, peak area CVs%), accuracy (94.2-108.6%), recovery (94.5-105.5%) and stability (3.8-8.1%, peak area CVs%) results. Moreover, LRSC derivatization significantly improved chromatographic resolution and MS detection sensitivity of NTs when compared with the reported studies through the introduction of a permanent charged moiety from LRSC into NTs. Taken together, this in situ DUADLLME method was successfully applied for the simultaneous determination of six NTs in biological samples.

Pre-analytical and analytical validations and clinical applications of a miniaturized, simple and cost-effective solid phase extraction combined with LC-MS/MS for the simultaneous determination of catecholamines and metanephrines in spot urine samples

It remains a challenge to simultaneously quantify catecholamines and metanephrines in a simple, sensitive and cost-effective manner due to pre-analytical and analytical constraints. Herein, we describe such a method consisting of a miniaturized sample preparation and selective LC-MS/MS detection by the use of second morning spot urine samples. Ten microliters of second morning urine sample were subjected to solid phase extraction on an Oasis HLB microplate upon complexation with phenylboronic acid. The analytes were well-resolved on a Luna PFP column followed by tandem mass spectrometric detection. Full validation and suitability of spot urine sampling and biological variation were investigated. The extraction recovery and matrix effect are 74.1–97.3% and 84.1–119.0%, respectively. The linearity range is 2.5–500, 0.5–500, 2.5–1250, 2.5–1250 and 0.5–1250ng/mL for norepinephrine, epinephrine, dopamine, normetanephrine and metanephrine, respectively. The intra- and inter-assay imprecisions are ≤9.4% for spiked quality control samples, and the respective recoveries are 97.2–112.5% and 95.9–104.0%. The Deming regression slope is 0.90–1.08, and the mean Bland-Altman percentage difference is from −3.29 to 11.85 between a published and proposed method (n=50). A correlation observed for the spot and 24h urine collections is significant (n=20, p<0.0001, r: 0.84–0.95, slope: 0.61–0.98). No statistical differences are found in day-to-day biological variability (n=20). Reference intervals are established for an apparently healthy population (n=88). The developed method, being practical, sensitive, reliable and cost-effective, is expected to set a new stage for routine testing, basic research and clinical applications.

An integrated liquid chromatography–tandem mass spectrometry approach for the ultra-sensitive determination of catecholamines in human peripheral blood mononuclear cells to assess neural-immune communication

Catecholamines play a vital role in the interactions between the nervous and immune systems and their dysfunctions are implicated in various autoimmune and neurological diseases. However, accurate quantitation of catecholamines in the immune system presents a special analytical challenge. We proposed the first LC–MS/MS method for the determination of catecholamines in human peripheral blood mononuclear cells (PBMC) with significantly improved sensitivity, selectivity and throughput without requiring derivatization, evaporation and ion-pairing reagent. PBMC were separated by density gradient centrifugation and lysed with 0.2M acetic acid. The analytical novelty includes the first solid phase extraction on a 96-well hydrophilic-lipophilic-balanced (HLB) μElution plate upon complexation with phenylboronic acid (PBA), enabling specific clean-up and fivefold pre-concentration of catecholamines in a single extraction. LC chromatographic separation was obtained on a PFP column with 0.01% HCOOH as additive with enhanced signal response. Summation of five MRM transitions yielded three–four fold rise in sensitivity. The lower limit of quantification of 1pg/mL for epinephrine (E) and 5pg/mL for norepinephrine (NE) and dopamine (DA) represents a considerable sensitivity improvement over available methods. Less than 8.7% of intraday and interday precision, 91.8–111.3% of accuracy and successful assessment of reference intervals for 40 healthy donors suggested good reproducibility and reliability of the assay. The novel PBA-HLB-PFP-MRM summation approach allows rapid, sensitive and reliable determination of catecholamines in PBMC, which will facilitate better understanding of the new arena of neural-immune network. Additionally, the substantially improved method can be modified to quantify catecholamines and metabolites in other biological matrices.

A simple and rapid analytical method based on solid-phase extraction and liquid chromatography–tandem mass spectrometry for the simultaneous determination of free catecholamines and metanephrines in urine and its application to routine clinical analysis

ObjectivesUrinary catecholamines and metanephrines are biochemical indicators of pheochromocytoma. We developed and validated a rapid and precise analytical method based on solid-phase extraction (SPE) and liquid chromatography separation coupled to tandem mass spectrometry (LC–MS/MS) for measuring urinary free catecholamines and metanephrines in a clinical setting. MethodsFollowing SPE purification of catecholamines and metanephrines from urine specimens, chromatographic separation and quantitative detection were performed using LC–MS/MS. The developed method for simultaneous measurement of urinary free catecholamines and metanephrines was validated with clinical urine specimens and was compared with other clinical and biochemical results, including urinary total metanephrines, vanillylmandelic acid (VMA), and plasma free metanephrines. ResultsThe performance of our newly developed method for measuring urinary free epinephrine (EPI), norepinephrine (NE), dopamine (DA), metanephrine (MN), and normetanephrine (NMN), was acceptable. The recoveries and matrix effects of analytes were 61–107% and 84.5–130.7%. The linear ranges of each analyte were 3.8–2163μg/L, 7.4–2,359μg/L, 5.4–2,825μg/L, 3.5–2,466μg/L, and 3.7–2,569μg/L, and the coefficients of variation (CV) were less than 10% with respect to imprecision. Carryover and sample stability were also validated. Validation using clinical urine specimens by comparison with various biochemical results showed that urinary free metanephrines had comparable sensitivity (100%) and superior specificity (97.1%) to urinary total and plasma free metanephrines. ConclusionsThe facile and reliable simultaneous measurement method for urinary free catecholamines and metanephrines using LC–MS/MS developed in this study is helpful in obtaining information about multiple metabolites and is applicable to routine clinical settings for the screening of pheochromocytoma.

Determination of catecholamines and related compounds in mouse urine using column-switching HPLC

We have developed an analytical method for the determination of catecholamines and related compounds in mouse urine by column-switching HPLC. Selective extraction of the catechol compounds was performed using a precolumn modified with phenylboronic acid, which has a pH dependent affinity for the catechol structures. The pretreatment buffer, which facilitated binding of the catechols to the precolumn, was optimized to ensure high analyte recoveries and good peak shapes. We found that using the same acetonitrile content in the pretreatment buffer and hydrophilic interaction liquid chromatography mobile phase was necessary to improve peak shapes. Eight catechol compounds were selectively extracted and separated using 100 mmol L(-1) ammonium formate/acetonitrile (20/80 v/v, pH 8.0) for the extraction step, and 20 mmol L(-1) ammonium formate (pH 2.5)/acetonitrile (20/80 v/v) for elution and separation. Native fluorescence of the separated catechol compounds was monitored, and the limits of detection, corresponding to a signal to noise ratio of 3, were 9-58 nmol L(-1). Five catechol compounds (dopamine, epinephrine, norepinephrine, 3,4-dihydroxyphenylglycol, and 3,4-dihydroxymandelic acid) were successfully quantified in mouse urine. Intra- and inter-day precisions were less than 10%, and performance was superior to that afforded by manual sample pretreatment.

Determination of ultra-trace catecholamines based on hot electron-induced cathodic electrochemiluminescence at a naturally oxide-covered tantalum electrode

A naturally oxide-covered tantalum electrode is firstly used in the detection of ultra-trace catecholamines based on hot electron-induced cathodic electrochemiluminescence with extremely low background, excellent sensitivity and perfect stability.

Determination of urinary catecholamines and metanephrines in cardiac deaths.

The aim of this study was to measure catecholamines and their O-methylated metabolites in urine and vitreous humor collected in cardiac deaths and noncardiac control cases that underwent medicolegal investigations. Our first goal was to assess whether cardiac events of different types are characterized by different catecholamine/metanephrine urine and/or vitreous profiles. Our second goal was to determine whether noncardiac causes of death with different survival intervals are characterized by different catecholamine/metanephrine urine and/or vitreous profiles. Two study groups were prospectively and retrospectively formed, a cardiac death group (including three subgroups, according to the cause of death) and a noncardiac death group (including two subgroups, according to the length of the agonal period). Postmortem angiography, autopsy, histology, toxicology, and biochemistry were performed in all cases. First results seem to indicate that absolute values measured in urine and vitreous for each of the analyzed markers display no significant differences relating to each of the tested cardiac death subgroups. In the control group, absolute concentrations measured in urine and vitreous for each of the analyzed parameters failed to show significant differences relating to the length of agonal period. Our preliminary findings do not seem to confirm the conclusions of former studies and fail to corroborate the usefulness of urine catecholamine and metanephrine analysis to characterize stress response intensity or length of the dying process in the postmortem setting.

Fast determination of catecholamines in human plasma using carboxyl-functionalized magnetic-carbon nanotube molecularly imprinted polymer followed by liquid chromatography-tandem quadrupole mass spectrometry

A novel, simple and sensitive method based on the use of dispersive micro-solid-phase extraction (d-μ-SPE) procedure combined with ultra-fast liquid chromatography–tandem quadrupole mass spectrometry (UFLC–MS/MS) for the determination of catecholamines, i.e., dopamine (DA), norepinephrine(NE) and epinephrine (E), was developed and validated. The novel catecholamines molecularly imprinted polymer (MIP) on the surface of carboxyl-functionalized magnetic-carbon nanotube (CF@m-CNTs-MIP) was synthesized and characterized by vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The CF@m-CNTs-MIP was used as the d-μ-SPE sorbent to extract catecholamines from human plasma samples. The obtained results demonstrated the higher extraction capacity of CF@m-CNTs-MIP with recoveries between 87.5–110%. The limits of quantification (LOQs) for NE, E and DA were 76ng/L, 18ng/L and 10ng/L, respectively. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of catecholamines in 120 healthy volunteers demonstrated the applicability to clinical studies.

Microfluorescent analysis for bioindication of ozone on unicellular plant systems

Various unicellular model plant systems, on which autofluorescence, fluorescence after histochemical treatment, and growth rates were investigated, have been proposed as bioindicators of ozone. Analysis is performed using fluorescent microscopy in different modifications, including microspectrofluorimetry and laser scanning confocal microscopy. It is found that low ozone doses (0.005 μLL−1 for 2.5-h exposure or 0.008 μLL−1 for 4-h exposure) do not affect or stimulate autofluorescence of the samples. In addition, vegetative microspores and pollen retain their ability to germinate in an artificial medium, and their growth is even enhanced. Higher ozone concentrations lead to either a decrease in the emission intensity or a shift of peaks in the fluorescence spectrum. In particular, 16-h exposure of vegetative microspores of horsetail to ozone (total dose 0.032 μLL−1) leads to occurrence of a new peak in the wavelength range of 515 to 520 nm in their autofluorescence spectrum. Exposure to high (more than 0.1 μLL−1) doses gives rise to a similar peak in the spectrum of leaf secretory hairs of Raphanus sativus. The spectrum of leaf secretory hairs of Fragaria viridis exhibits a decrease in the emission intensity at wavelengths of 520 to 550 nm. Stress metabolites have been revealed by fluorescence at wavelengths from 460 to 480 nm after specific histochemical reactions for determination of catecholamines or histamine. After exposure in ozone to a total dose of 0.012 μLL−1, a significant increase in the amount of catecholamines and the histamine content was observed for pollen of Populus balsamifera. Higher concentrations of catecholamines (in comparison with control samples) are found in vegetative microspores of Equisetum arvense and pollen of Corylus avellana and Populus balsamifera after exposure in ozone to high doses (0.032 μLL−1), whereas a decrease in the catecholamine concentration was observed for pollen of Tulipa hybridum and Dolichothele albescens after this treatment.

Establishment of a LC-MS/MS for the determination of urinary catecholamines

Establishment of a LC-MS/MS for the determination of urinary catecholamines

Effects of huwentoxin-I on catecholamines in cultured PC12 cells

The measurement of catecholamines in biological samples remains a current analytical challenge in the study on neurotransmitter release, although much effort has been devoted toward the relevant methodology. Here we first established a fluoresence-based method for the quantitative determination of catecholamines and then applied it to the investigation of effects of huwentoxin-I (HWTX-I), a peptide neurotoxin, on catecholamines in cultured PC12 cells. The results showed that treatment with HWTX-I at different concentrations (10, 50, 100 and 1000 nM) for 20 min significantly increased dopamine (DA) content in the culture medium (p < 0.01), with ∼1.6-fold increase compared with that of the control at the highest concentration tested. Within 20 min, DA content in the medium increased with increasing the treatment time. In contrast, HWTX-I decreased norepinephrine (NE) content in the medium. However, after the PC12 cells were treated with HWTX-I, the intracellular contents of both DA and NE were kept at a relatively constant level. These data suggest that HWTX-I differentially affects the DA and NE of the neuroendocrine cells, with enhancing the actions of DA and weakening those of NE.

Determination of catecholamines and their metabolites in rat urine by ultra-performance liquid chromatography-tandem mass spectrometry for the study of identifying potential markers for Alzheimer's disease.

In order to investigate the potential links between catecholamines (CAs) and Alzheimer's disease (AD), rapid and sensitive ultra-performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS) methods in different ionization modes for the quantification of 14 CAs and their metabolites in rat urine without derivatization or complex sample pre-treatments were developed. After addition of the internal standard, isoproterenol, the urine samples were extracted by protein precipitation and separated on an Inertsil ODS-EP column (Shimadzu, Japan) at a flow of 1.0 ml min(-1). Tandem mass spectrometric detection was performed on a 4000Q UPLC-MS/MS in the multiple reaction monitoring mode with turbo ion spray source. Tyrosine, dopamine, noradrenaline, epinephrine, 3-methoxytyramine, normetanephrine and metanephrine were determined in positive mode, while 3,4-dihyroxy-L-phenylalanine (DOPA), 3,4-dihydroxyphenylacetic acid, DL-3,4-dihydroxymandelic acid, DL-3,4-dihydroxyphenyl glycol, homovanillic acid, DL-4-hydroxy-3-methoxymandelic acid and 4-hydroxy-3-methoxy-phenylglycol were determined in negative mode. The methods were examined and were found to be precise and accurate within the linearity range of the assays. The intra-day and inter-day precision and accuracy of the analytes were well within acceptance criteria (±15%). The mean extraction recoveries of analytes and internal standard were all more than 60%. The validated methods have been successfully applied to compare CAs profiles in normal and AD rats. The results indicated the urine levels of DL-3,4-dihydroxyphenyl glycol and 4-hydroxy-3-methoxy-phenylglycol in AD rats were significantly higher than those in the normal group, and the other CAs have an opposite performance. These may attribute to the difference of some enzyme activity between rats with AD and normal. Furthermore, this may be helpful in clinical diagnostics and monitor the efficacy of AD treatment.