Determination Of Catecholamines Research Articles

Spectrophotometric Determination of Norepinephrine in Industrial Equipment Cleaning Rinse Water by Its Own Absorbance and The Tollens’ Reagent

A literature review of the available spectrophotometric methods of determination of catecholamines is presented. Based on this review, two simple spectrophotometric methods for the determination of norepinephrine bitartrate in pharmaceutical formulations and industrial equipment cleaning rinse waters were chosen and validated. The first method for the determination of norepinephrine at ppm levels utilizes the absorbance band of the solution of norepinephrine bitartrate at 279 nm. The second method for the determination of norepinephrine at ppb levels is based on the reaction of norepinephrine with the Tollens’ reagent in the presence of the cationic surfactant cetylpyridinium chloride and the colorimetric determination of the formed colloidal silver nanoparticles. The calibration graphs are linear in the range from 1 to 150 mg/l of norepinephrine for the first method and 25 µg/l to 10 mg/l for the second method. The molar attenuation coefficients are 388 and 7560 m2/mol, respectively, the limits of detection are 1.1 mg/l and 3.1 µg/l, and the limits of quantification are 3.3 mg/l and 9.4 µg/l, respectively. Both methods are selective concerning the common excipients, show good accuracy (the relative uncertainties do not exceed 4 and 7%, respectively) and precision (the relative standard deviations do not exceed 4 and 7%, respectively), and do not require lengthy sample preparation and sophisticated laboratory equipment.

Silica nanodots: Luminescent effects and insights for the determination of catecholamines

The effect of various catecholamines on the luminescent properties of silica nanodots (SiNDs) was studied and the new method using SiNDs that represent a promising green alternative to other analytical techniques for the determination of catecholamines has been developed. A change in spectral properties of SiNDs in the presence of catecholamines occurs, depending on the nature of the substance. Dopamine causes a decrease in the luminescence intensity of SiNDs at 445 nm whereas in the presence of norepinephrine and epinephrine a maximum appears in the luminescence spectrum of SiNDs at 500 and 510 nm, respectively. The intensity at 445 nm or the ratio of the intensities at 500 (510) nm and 445 nm can be used as analytical signals for the determination of the corresponding catecholamines. Limits of detection for dopamine, norepinephrine and epinephrine are 2, 0.06, and 0.14 µM, respectively.

Особенности течения постковидного синдрома, его влияние на качество жизни и некоторые показатели гемостаза и обмена катехоламинов

The novel COVID-19 coronavirus infection is known to be characterized by recovery in most cases, but long-term sequelae persist in 10–20% of survivors. To date, the pathophysiologic characterization and clinical significance of the impact of SARSCoV-2 on endocrine organs, as well as the impact of the associated endocrine dysfunction on the prognosis of COVID-19 survivors, have not been fully explored and are not sufficiently reported in the literature. It has been suggested that catecholamines, especially in excessive concentrations, cause dysregulation of physiologic cascades, which may be closely related to unfavorable outcomes in COVID-19. The objective of the work was to determine the diagnostic significance of hemostasis and catecholamine metabolism indices in COVID-19 patients with and without post-COVID-19 syndrome, their correlation with the reported cognitive impairments. Patients and methods. 90 patients – 14 males and 76 females – who underwent COVID-19 without consequences in the form of post-COVID-19 syndrome (PCS) were examined, and the main group included patients with PCS. Patients underwent laboratory examination: coagulogram, determination of P-selectin level and daily urine examination with determination of catecholamines, catecholamine and serotonin metabolites (adrenaline, noradrenaline, dopamine, homovanillic acid, vanillylmindalic acid, 5-hydroxyindoleacetic acid). The main group consisted of 60 patients with PCS (9 (15%) men, 51 (85%) women, and the control group consisted of 30 patients without PCS (5 (16.7%) men, 25 (83.3%) women. Patients in the control group more often carried COVID-19 asymptomatically or in a non-serious form without lung damage, while patients in the main group with lung damage in 21.7% of cases. Results. The duration of PCS ranged from 4 to 36 months at the time of examination, with a median of 24 months. Its manifestation was maximal in 43.3%. Decreased quality of life associated with COVID-19 was noted by 53.3% of patients in the main group. Complaints of cognitive impairment (CI) were the most frequent in the structure of PCS in 53 patients (88.3%). The duration of CI was less than a year in 21.7%, one to two years – 15%, two and more years – 55%. Evaluation of CI severity on a five-point scale: 1 point – 10%, 2 point – 20%, 3 point – 35%, 4 point – 18,3%, 5 point – 8,3%. The predominant CI patterns were impaired concentration 78.3%, (24 [12; 35.5] months), memory 71.7%, (24 [10.5; 35.5] months), lethargy 53.3%, (12 [6; 24] months), brain fog 51.7%, (12 [7; 24] months). In the main group, 30% of patients and 10% of patients in the control group (p = 0.034) had CI according to MoCA scale (less than 26 scores). Patients in the main group with CI according to MoCA scale presented problems for 2 or more years in 55.6% of cases, less than a year – 22.2%, from a year to 2 years – in 11.1%. The presence of at least 1 symptom was noted by 88.3% of respondents. According to the results of laboratory methods, the median level of adrenaline in daily urine was higher in the main group (p = 0.025). No statistically significant difference was found in the study of hemostasis parameters between the two groups. Key words: hemostasis, catecholamines, quality of life, post-coital syndrome, scales

Asymmetric Adrenals: Sexual Dimorphism of Adrenal Tumors.

Sexual dimorphism has direct consequences on the incidence and survival of cancer. Early and accurate diagnosis is crucial to improve prognosis. This work aimed to characterized the influence of sex and adrenal asymmetry on the emergence of adrenal tumors. We conducted a multicenter, observational study involving 8037 patients with adrenal tumors, including adrenocortical carcinoma (ACC), aldosterone-producing adenoma (APA), cortisol-secreting adrenocortical adenomas (CSAs), non-aldosterone-producing adrenal cortical adenoma (NAPACA), pheochromocytoma (PCC), and neuroblastoma (NB), and investigated tumor lateralization according to sex. Human adrenal tissues (n = 20) were analyzed with a multiomics approach that allows determination of gene expression, catecholamine, and steroid contents in a single sample. In addition, we performed a literature review of computed tomography and magnetic resonance imaging-based studies examining adrenal gland size. ACC (n = 1858); CSA (n = 68), NAPACA (n = 2174), and PCC (n = 1824) were more common in females than in males (female-to-male ratio: 1.1:1-3.8:1), whereas NBs (n = 2320) and APAs (n = 228) were less prevalent in females (0.8:1). ACC, APA, CSA, NAPACA, and NB occurred more frequently in the left than in the right adrenal (left-to-right ratio: 1.1:1-1.8:1), whereas PCC arose more often in the right than in the left adrenal (0.8:1). In both sexes, the left adrenal was larger than the right adrenal; females have smaller adrenals than males. Adrenal asymmetry in both sexes may be related to the pathogenesis of adrenal tumors and should be considered during the diagnosis of these tumors.

Development of spectrophotometric method for the determination of catecholamines in pure and pharmaceutical formulations, using pyromellitic dianhydride reagent by charge transfer reaction

Development of spectrophotometric method for the determination of catecholamines in pure and pharmaceutical formulations, using pyromellitic dianhydride reagent by charge transfer reaction

Iron Single‐Atom Catalysts on MXenes for Ultrasensitive Monitoring of Adrenal Tumor Markers and Cellular Dopamine

AbstractNeuroblastoma and pheochromocytoma are the most prevalent malignancies of the adrenal medulla. They are currently diagnosed by measuring urinary catecholamines using high‐performance liquid chromatography‐mass spectrometry, which is expensive, bulky, and tedious. Electrochemical detectors stand out as low‐cost alternatives; however, further development of functional materials with adequate sensitivity is still required to attain clinically useful diagnostic devices. Here, Ti3C2Tx MXene nanosheets stabilized with iron single‐atom catalysts (Fe‐SACs), anchored on the surface, are synthesized and utilized as efficient electrocatalysts for the determination of catecholamine (dopamine (DA)) and its end‐products (vanillylmandelic acid (VMA) and homovanillic acid (HVA)). The Fe‐SACs/Ti3C2Tx exhibits low oxidation overpotentials with high signal amplifications up to 610%, 290%, and 420%, and sensitive detection limits of 1.0, 5.0, and 10 nM for DA, VMA, and HVA, respectively. The presence of the atomic Fe elements on the Ti3C2Tx nanosheets is confirmed using high‐resolution scanning transmission electron microscopy and X‐ray photoelectron spectroscopy. The Fe‐SACs/Ti3C2Tx sensor tracks the in situ production of DA in PC12 cells and found practically useful in analyzing human urine samples. The Fe‐SACs/Ti3C2Tx stands out as a sensitive diagnostic platform for evaluating the progression of tumors and the quality of cellular DA communications

Determination of Catecholamines in a Small Volume (25μL) of Plasma from Conscious Mouse Tail Vein.

The determination of plasma catecholamine levels is commonly used as a measure of the sympathetic nervous system's response to stress and is highly important for diagnosis, therapy, and prognosis of cardiovascular diseases, catecholamine-secreting tumors arising from the chromaffin cells of the sympathoadrenal system, and affective disorders. Diseases in which catecholamines are significantly elevated include pheochromocytoma, Parkinson's disease, Alzheimer's disease, neuroblastoma, ganglioneuroblastoma, von Hippel-Lindau disease, baroreflex failure, chemodectina (nonchromaffin paraganglioma), and multiple endocrine neoplasia. Plasma norepinephrine levels provide a guide to prognosis in patients with stable, chronic, and congestive heart diseases. The method described here for the determination of plasma catecholamines is based on the principle that plasma catecholamines are selectively adsorbed on acid-washed alumina at pH 8.7 and then eluted at a pH between 1.0 and 2.0. Upon injection, catecholamines in elutes were separated by a reversed phase C-18 column. After separation, the catecholamines present within the mobile phase enter the electrochemical detector. Electrochemical detection occurs because electroactive compounds oxidize at a certain potential and thereby liberate electrons that create measurable current. Catecholamines readily form quinones under these conditions, get oxidized, release two electrons, and create current. The electrochemical detector detects this electrical current that linearly correlates to the catecholamine concentration loaded into the ultra-performance liquid chromatography instrument. A 15-min mixing time during the adsorption and desorption steps was found to be optimal. If the washing step was omitted, the catecholamines could not be eluted from the acid-washed alumina. To prevent dilution, the alumina had to be centrifuged and not aspirated to dryness after the washing step. We report here that by changing the range in the electrochemical detector, plasma catecholamines were measured with only 12.5μL of plasma and more reliably with 25μL of plasma. The detection limit was 1ng/mL. This assay method is very useful as blood can be collected from the tail vein in a conscious mouse and the same mouse can be used for time-dependent or age-dependent studies.

Brain fog in neuropathic postural tachycardia syndrome may be associated with autonomic hyperarousal and improves after water drinking.

BackgroundBrain fog is a common and highly disturbing symptom for patients with neuropathic postural tachycardia syndrome (POTS). Cognitive deficits have been measured exclusively in the upright body position and mainly comprised impairments of higher cognitive functions. The cause of brain fog is still unclear today. This study aimed to investigate whether increased autonomic activation might be an underlying mechanism for the occurrence of brain fog in neuropathic POTS. We therefore investigated cognitive function in patients with neuropathic POTS and a healthy control group depending on body position and in relation to catecholamine release as a sensitive indicator of acute stress. The second aim was to test the effect of water intake on cardiovascular regulation, orthostatic symptoms, cognitive function and catecholamine release.MethodsThirteen patients with neuropathic POTS and 15 healthy control subjects were included. All participants completed a total of four rounds of cognitive testing: two before and two after the intake of 500 ml still water, each first in the supine position and then during head-up tilt. At the end of each cognitive test, a blood sample was collected for determination of plasma catecholamines. After each head-up tilt phase participants were asked to rate their current symptoms on a visual analogue scale.ResultsWorking memory performance in the upright body position was impaired in patients, which was associated with self-reported symptom severity. Patients had elevated plasma norepinephrine independent of body position and water intake that increased excessively in the upright body position. The excessive increase of plasma norepinephrine was related to heart rate and symptom severity. Water intake in patients decreased norepinephrine concentrations and heart rate, and improved symptoms as well as cognitive performance.ConclusionBrain fog and symptom severity in neuropathic POTS are paralleled by an excessive norepinephrine secretion. Bolus water drinking down-regulates norepinephrine secretion and improves general symptom severity including brain fog.

Current Sample Preparation Methodologies for Determination of Catecholamines and Their Metabolites.

Catecholamines (CAs) and their metabolites play significant roles in many physiological processes. Changes in CAs concentration in vivo can serve as potential indicators for the diagnosis of several diseases such as pheochromocytoma and paraganglioma. Thus, the accurate quantification of CAs and their metabolites in biological samples is quite important and has attracted great research interest. However, due to their extremely low concentrations and numerous co-existing biological interferences, direct analysis of these endogenous compounds often suffers from severe difficulties. Employing suitable sample preparation techniques before instrument detection to enrich the target analytes and remove the interferences is a practicable and straightforward approach. To date, many sample preparation techniques such as solid-phase extraction (SPE), and liquid-liquid extraction (LLE) have been utilized to extract CAs and their metabolites from various biological samples. More recently, several modern techniques such as solid-phase microextraction (SPME), liquid–liquid microextraction (LLME), dispersive solid-phase extraction (DSPE), and chemical derivatizations have also been used with certain advanced features of automation and miniaturization. There are no review articles with the emphasis on sample preparations for the determination of catecholamine neurotransmitters in biological samples. Thus, this review aims to summarize recent progress and advances from 2015 to 2021, with emphasis on the sample preparation techniques combined with separation-based detection methods such capillary electrophoresis (CE) or liquid chromatography (LC) with various detectors. The current review manuscript would be helpful for the researchers with their research interests in diagnostic analysis and biological systems to choose suitable sample pretreatment and detection methods.

Sensitive enzymatic determination of neurotransmitters in artificial sweat

Dopamine (DA) and epinephrine (EN) are two phenolic molecules that are used in the human body and secreted in the brain actuating as neurotransmitters. As both molecules are highly important in the brain and the central nervous system, monitoring of their concentrations would enable better understanding of their importance and role in different physiological conditions. Copper efflux oxidase from Escherichia coli was shown in the past to have the ability of oxidizing polyphenolic compounds. As such, we have engineered this enzyme for its site-specific attachment to an electrode for the detection of DA and EN in high resolution and sensitivity. Here we present an enzymatic biosensor that enables the detection of such molecules with a 10 nM resolution and a linear range of up to 100 nM in artificial sweat samples. The presented biosensor could be used for the determination of catecholamines in different bodily fluids.

UPLC-MS/MS assay for the simultaneous determination of catecholamines and their metabolites at low pg/mg in rat/mouse striatum

Catecholamines and their metabolites act as neurotransmitters in the brain and are important for nervous system function. In the current work, a highly selective and sensitive UPLC-MS/MS assay was developed for quantitation of six catecholamines and their metabolites, including dopamine, norepinephrine, serotonin, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindolacetic acid from rat and mouse striatum as pharmacodynamic biomarkers to support neuroscience and pharmaceutical research. A fit-for-purpose strategy for method development, assay qualification and study support were adopted for this assay. A surrogate matrix (brain homogenizing solution absent of targeted analytes) was used for preparation of calibration samples and certain levels of quality control samples to avoid interference from endogenous baselines. Homogenized rodent striatum was derivatized by dansyl chloride to enhance the sensitivity, followed by liquid-liquid extraction with ethyl acetate in 96-well plate format. The lower limit of quantitation (LLOQ) was 0.2 ng/mL in tissue homogenate, equivalent to 3.2 pg/mg in brain tissue, which could be further reduced to ten times lower by changing the re-dissolving and injecting volume in the last sample purification step. Acceptable accuracy, precision, linearity, specificity, recovery, and matrix effect was obtained. Bench-top stability (2 h), freeze-thaw stability (3 cycles at −20 °C), and − 80 °C storage stability (up to 51 days) in both tissue homogenate and surrogate matrix along with autosampler stability (60 h at 4°C) all met acceptance criteria. This assay was successfully applied to measure the six analytes in striatum from mice treated with the neurotoxin 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), an animal model of Parkinsonism for which dosing protocols can vary widely, and further confirmed the metabolic pathway of neurotoxicity by the quantification of catecholamine metabolites. Our study is the first detailed the step-by-step recovery and pointed out the key factors for the assay to simultaneously quantify these six neurotransmitters in rodent striatum with superior sensitivity.

Fabrication of Electrochemical Sensor for Epinine Determination Amplified with MgO/CNTs Nanocomposite and Ionic Liquid

Background:Catecholamines are a large group of pharmacological and biological compounds that are widely used in biological systems. These compounds are prepared both naturally and synthetically with many key roles in the human body and its activities. Therefore, many researchers focused on the identification and determination of catecholamines in biological samples.Methods:MgO/SWCNTs were synthesized through the chemical precipitation method. In addition, cyclic voltammetry, differential pulse voltammetry, and chronoamperometric methods were used for the electro-oxidation reaction study of epinine at the surface of the modified electrode.Results:Carbon paste electrode (CPE) modified with MgO/SWCNTs nanocomposite and 1-butyl- 3-methylimidazolium methanesulfonate (BMMS) was used as an electrochemical sensor for the determination of epinine. The results showed a linear dynamic range of 5.0 nM-250 μM with a detection limit of 0.1 nM for epinine determination using MgO/SWCNTs/BMMS/CPE as a sensor.Conclusion:In the present study, a highly sensitive electrochemical sensor was designed and fabricated as an analytical tool for the determination of epinine. MgO/SWCNTs/BMMS/CPE was successfully used for the determination of epinine in water and dextrose saline with an acceptable recovery range of 98.7%-102.72%.

A simultaneous extraction/derivatization strategy coupled with liquid chromatography–tandem mass spectrometry for the determination of free catecholamines in biological fluids

The current study presents a convenient, rapid and effective simultaneous extraction/derivatization (SEDP) strategy for effective pretreatment of catecholamines (CAs). Commercial zirconium oxide (ZrO2) nanoparticles were employed for the selective capturing of cis-diol containing CAs to remove the biological interferences and phenyl isothiocyanate (PITC) was used for derivatization to improve the ionization and to improve the chromatographic separation. The extraction and derivatization procedures were integrated into one step to simplify the sample pretreatment. Excessive derivatization reagents were removed as well, reducing the degree of contaminations in mass spectrometry. The factors affecting the SEDP process were optimized and the results showed that the detection sensitivity and chromatographic separation of CAs greatly improved compared with underivatized CAs, during LC-MS/MS analysis. Combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), quantifying the concentration of norepinephrine (NE), epinephrine (E) and dopamine (DA) in biological fluids was validated in ranges of 1-200.0 ng/mL with a satisfactory correlation coefficient (R2 > 0.997). The obtained recoveries were in the range of 91.0-109.5% with RSDs less than 9.4%. Finally, significant changes in CAs levels in urine samples of healthy people and pheochromocytoma patients were detected. The developed method offers comparative advantages in terms of sensitivity, specificity and selectivity.

A novel sensitive colorimetric determination of catecholamine drug in dosage form via oxidative coupling reaction with MBTH and potassium ferricyanide

A new and direct colorimetric method has been established for the determination of catecholamine (methyldopa, MD) in both pure form and in pharmaceutical formulations. The method is based on the oxidative coupling reaction of MD with 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH) and potassium ferricyanide at pH 10.4 in aqueous medium to form an orange product that has a maximum absorption at 460 nm. Beer's law plot showed good correlation in the concentration range of 1.0−56.0 µg mL-1, with detection limit of 0.31 µg mL-1. Molar absorptivity for the above method was found to be 6.56×103 L mol-1 cm-1. All the measurements were carried out at 25 ± 1.0 °C, the formation constant (logKf) value of colored species is 9.48 and the standard free energy (DG‡) is − 54.09 KJ mol-1. This method was applied successfully to determination of MD in tablets and the results were compared with the USP method. Common excipients used as additives in tablets do not interfere in the proposed method. The method is accurate, precise and highly reproducible, while being simple, cheap and less time consuming and hence can be suitably applied for routine analysis of MD in bulk and dosage forms.

Magnetic borate-modified Mxene: A highly affinity material for the extraction of catecholamines

A novel magnetic borate-modified MXene composite was prepared by in situ growth of Fe3O4 particles onto the surface of phenylboronic acid modified Ti3C2Tx nanosheets. The magnetic composite possesses highly selective recognition properties to catecholamines, and high adsorption capacity (up to 319.6 μmol g−1) for dopamine. Besides, the adsorption of urinary catecholamines can be accomplished within 2.0 min. The excellent adsorption performance can be assigned to its unique 2D layered structures, which helps to shorten the diffusion path and facilitate molecular transport. In addition, the multilayer adsorption and the synergetic interactions of borate affinity, van der Waals forces, hydrogen bonding and π-π stacking also contribute to the adsorption. By coupling the magnetic boronate affinity composites with high-performance liquid chromatography-fluorescence detection, a sensitive method for the determination of catecholamines in urine samples was proposed. The validation results revealed it can offer good linearities (correlation coefficients higher than 99%). The method detection limits were 0.06, 0.16, 0.03 and 0.14 ng mL−1 for norepinephrine, epinephrine, dopamine and isoprenaline, respectively, and relative recoveries for these catecholamines were in the range of 98.56–108.1%, 92.56–110.0%, 98.79–112.3% and 88.14–97.81%, respectively. The proposed method was successfully applied to analyze the catecholamines in the urine samples from 15 healthy volunteers and 16 patients with Alzheimer's disease. The results indicated that the magnetic borate-modified Mxene composite possesses superior extraction performance, and can be used as an outstanding candidate for the extraction of catecholamines in pre-clinical or clinical studies.

Tannic acid-directed synthesis of magnetic and boronic acid-functionalized metal-organic frameworks for selective extraction and quantification of catecholamines in human urine.

Anovel magnetic borate-functionalized metal-organic framework nanocomposite was designed and fabricated for selective enrichment of catecholamines from human urine. Firstly, the polytannic acid (PTA) layer with natural low-cost and ecofriendly polyphenol tannic acid as the organic ligand and Fe3+ as the cross-linker was coated onto the surface of Fe3O4. Then, the borate-functionalized metal-organic framework (MIL-100(Fe)-B) with 5-boronobenzene-1,3-dicarboxylic acid as a ligand fragment was modified onto the PTA-coated Fe3O4 through a metal-ligand-fragment coassembly strategy. The obtained smart porous adsorbent Fe3O4@PTA@MIL-100(Fe)-B was confirmed by means of several characterization methods and then applied as an effective magnetic solid phase extraction (MSPE) sorbent for specific extraction of trace catecholamines in human urine. The Plackett-Burman design was used for screening the variables significantly affecting the extraction efficiency. Then, the significant factors were further investigated by the Box-Behnken design to determine the optimal extraction conditions. Under the optimal conditions, a method for selective MSPE combined with high-performance liquid chromatography with a fluorescence detector for the quantitation of catecholamines in human urine was developed and validated. With the proposed method, the linearity range was from 0.500 to 500ngmL-1 for norepinephrine and epinephrine and from 1.00 to 500ngmL-1 for dopamine. The detection limits were 0.050, 0.11, and 0.20ngmL-1 for norepinephrine, epinephrine, and dopamine, respectively. The recoveries from spiking experiments varied from 91.5 to 108% with relative standard deviations (RSDs) of 0.80-4.8%. The established method israpid, sensitive, accurate, inexpensive, and ecofriendly and was successfully applied to the determination of the target catecholamines in human urine samples.

A 3-min UPLC-MS/MS method for the simultaneous determination of plasma catecholamines and their metabolites: Method verification and diagnostic efficiency

ObjectiveTo verify a rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the quantification of catecholamines and their metabolites, and to validate its efficiency for the diagnosis of phaeochromocytomas and paragangliomas (PPGLs). MethodsPlasma samples were pretreated with solid-phase extraction, followed by a 3-min UPLC-MS/MS analysis to quantify epinephrine (E), norepinephrine (NE), dopamine (DA), metanephrine (MN), normetanephrine (NMN) and 3-methoxytyramine (3-MT), simultaneously. The UPLC-MS/MS method was comprehensively verified and its diagnostic efficiency on PPGLs was tested using 7 PPGLs and 408 non-PPGLs patient plasma samples. ResultsUsing the developed method, the limit of detections (LODs) of the 6 analytes ranged from 0.0002 nmol/L (MN) to 0.0250 nmol/L (NE), while the lower limit of measuring intervals (LLMIs) ranged from 0.05 nmol/L (E, MN and NMN) to 0.10 nmol/L (NE and DA). The reportable ranges were 0.05–30.00 nmol/L for E, MN and NMN, 0.10–30.00 nmol/L for NE and DA, 1.00–300.00 pg/mL for 3-MT. No significant matrix effect was detected after correcting using internal standard. Besides, intra-day and inter-day precision were also within acceptance criteria with coefficient of variations (CVs) ≤ 15% and recoveries ranged from 95% to 115% for all the 6 analytes. The carryover effect was lower than 10%. Its diagnostic efficiency for PPGLs was significantly increased, the areas under the receiver operating characteristic (ROC) curves were increased from 68.7% to 89.1% (using E, NE and DA) to 75.2%–99.9% (using MN, NMN and 3-MT). ConclusionThis study verified a rapid UPLC-MS/MS method for the determination of catecholamines and their metabolites in human plasma. It showed high diagnostic efficiency and will serve as an important tool to avoid the risk for missing patients with PPGLs.

Label-free silver triangular nanoplates for spectrophotometric determination of catecholamines and their metabolites

A novel method towards spectrophotometric determination of catecholamines and their metabolites differing in their functional groups has been developed. This method is based on a change in morphology of silver triangular nanoplates upon the action of cateсholamines and their metabolites, which is manifested by the decrease of the nanoparticle local surface plasmon resonance (LSPR) band intensity or its shift to the short-wavelength region of the spectrum. The shift value of the LSPR band or the change of its intensity increases with increasing concentration of catecholamines or their metabolites, which isproposed for their spectrophotometric determination. The limits of detection of catecholamines and their metabolites underselected conditions increase in the series homovanillic acid < vanillylmandelic acid < L-epinephrine < L-norepinephrine < dopamine and are 0.25, 1.2, 3.0, 64, and 130μmolL-1, respectively. The selectivity of the proposed method was assessedusingvanillylmandelic acidas example. It was found that the determination of vanillylmandelic acid does is not interferedin the presence of4000-fold excessof Na+, K+, CH3COO-, and 1000-fold excess of Mg2+, Ca2+, Al3+, NO3-. The method also allows for the selective determination of vanillylmandelic acid in the presence of a 1000-fold excess of structurally related substances that do not contain either a catechol fragment or an electron donor substituent. The proposed approach was successfully applied to the determination of catecholamines in pharmaceuticals and artificial urine. Graphical abstract.

Quantitation using HRMS: A new tool for rapid, specific and sensitive determination of catecholamines and deconjugated methanephrines metanephrines in urine

Urinary catecholamines and their methylated metabolites are biochemical indicators of pheochromocytoma, paraganglioma and neuroblastoma. A rapid and precise analytical method based on solid-phase extraction (SPE) and liquid chromatography separation coupled to high-resolution mass spectrometry (LC-HRMS) was developed and validated to measure urinary catecholamines (epinephrine (E), norepinephrine (NorE), dopamine (D)) and total methylated metabolites (normetanephrine (NorMN), metanephrine(MN) and 3-methoxytyramine (3-MT)) in a clinical setting. Results of 51 urine specimens measured using this LC-HRMS method were compared with a liquid chromatography assay with electrochemical detection (LC-EC). Urine samples (200 μL) were spiked with an internal standard solution followed by SPE purification. In the case of total methylated metabolites, urine was hydrolyzed before SPE purification. Separation was achieved on an Acclaim Mixed Mode WCX column, with an 8.5 min runtime. All compounds were detected in electrospray positive ionization mode with a parallel reaction monitoring acquisition and quantified with a linear regression (r2 > 0.998) between 2 and 200 µg/L (10.9–1090; 11.8–1182 nmol/L) for E and NorE respectively and between 10 and 1000 µg/L for others (65.2–6520; 50.7–5070; 54.5–5450 ; 59.8–5980 nmol/L for D, M, NorMN and 3-MT, respectively). Overall imprecision and bias did not exceed 15%. No significant matrix effect was observed. Correlation between the two assays was good except for epinephrine. Epinephrine concentrations measured by LC-EC method were slightly higher than values obtained with LC-HRMS method but without impact on clinical decision. This LC-HRMS assay provides a new tool for simultaneous quantitative catecholamine determination and was successfully applied in routine for the screening or follow up of pheochromocytoma, paraganglioma and neuroblastoma. LC-HRMS method offers significant advantages compared to LC-EC with good sensitivity, an unambiguous analyte determination and high sample throughput.

Gold nanorods and their nanocomposites based on polyurethane foam for determination of catecholamines in biological fluids

Capability of gold nanorods and their nanocomposites based on polyurethane foam as spectrophotometric reagents for catecholamines determination was examined. Comparison of the analytical properties of the systems based on interaction of nanoparticles of different morphology with various reagents in the presence of catecholamines was carried out, gold nanorods-based system is characterized by the highest sensitivity. Applicability of gold nanorods and their nanocomposites for catecholamines determination in biological fluids (urine, serum) was proved by HPLC analysis. Catecholamines preconcentration by dynamic sorption on hypercrosslinked polystyrene and further elution with 6M acetic acid could serve to improve the sensitivity of the analysis.