Determination of epinephrine in human serum using a Pt electrode modified by polyaniline–poly(3-methylthiophene)–poly(3,3′-diaminobenzidine)

2015 ◽  
Vol 93 (11) ◽  
pp. 1239-1244 ◽  
Author(s):  
Emine Ülker ◽  
Muammer Kavanoz
Keyword(s):  
Human Serum ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Oxidation Potential ◽  
Serum Samples ◽  
Pt Electrode ◽  
Limit Of Quantification ◽  
Amperometric Determination ◽  
Best Response

A Pt electrode modified by polyaniline–poly(3-methylthiophene)–poly(3,3′-diaminobenzidine) was used for amperometric determination of epinephrine in a solution of NaHSO4/Na2SO4 (pH 2.0). For these studies, potentials between 0.40 and 0.50 V were applied, and the best response was obtained at 0.45 V. The limit of detection, limit of quantification, and the linear dynamic range were 1.23 × 10−4, 4.10 × 10−4, and 4.10 × 10−4 to 100.0 mmol L−1, respectively. These results were compared with determinations using Pt electrodes that were coated and uncoated with homopolymers. To check the accuracy of the developed method and the matrices interference, determination of epinephrine was performed in human serum samples using this modified electrode. The epinephrine concentrations were adjusted to 1.0 and 5.0 mmol L−1, and recovery values were calculated as 100.4% and 96.8%, respectively. It is significant that the determination of epinephrine was carried out at a lower potential (0.45 V) than the oxidation potential of epinephrine (0.65 V) without any matrix effect.

scholarly journals Conductimetric Biosensor for the Detection of Uric Acid by Immobilization Uricase on Nata de Coco Membrane—Pt Electrode

2011 ◽  
Vol 6 ◽  
pp. ACI.S7346 ◽  
Author(s):  
Ani Mulyasuryani ◽  
Arie Srihardiastutie
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Candida Utilis ◽  
Medical Laboratory ◽  
Membrane Thickness ◽  
Serum Samples ◽  
Ph Change ◽  
Pt Electrode ◽  
Enzyme Biosensor

A conductimetric enzyme biosensor for uric acid detection has been developed. The uricase, as enzyme, is isolated from Candida utilis and immobilized on a nata de coco membrane-Pt electrode. The biosensor demonstrates a linear response to urate over the concentration range 1-6 ppm and has good selectivity properties. The response is affected by the membrane thickness and pH change in the range 7.5-9.5. The response time is three minutes in aqueous solutions and in human serum samples. Application of the biosensor to the determination of uric acid in human serum gave results that compared favourably with those obtained by medical laboratory. The operational stability of the biosensor was not less than three days and the relative error is smaller than 10%.

scholarly journals Determination of uric acid in human serum by an enzymatic method using N-methyl-N-(4-aminophenyl)-3-methoxyaniline reagent

2003 ◽  
Vol 68 (8-9) ◽  
pp. 691-698 ◽  
Author(s):  
Milena Jelikic-Stankov ◽  
Predrag Djurdjevic ◽  
Dejan Stankov
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Limit Of Detection ◽  
Ascorbate Oxidase ◽  
Acid Oxidation ◽  
Uric Acid Concentration ◽  
Enzymatic Method ◽  
Limit Of Quantification ◽  
Relative Standard

In this work a new enzymatic method for the determination of uric acid in human serum has been developed. The method is based on the oxidative coupling reaction between the N-methyl-N-(4-aminophenyl)-3-methoxyaniline (NCP) reagent and the hydrogen ? donor reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline (TOOS), in the system involving three enzymes: uricase, peroxidase and ascorbate oxidase. Using this method uric acid could be determined in concentrations up to 1.428 mmol/L, with a relative standard deviation of up to 1.8 %. The effect of the medium pH and the NCP concentration on the linearity of the chromogen absorbance versus the uric acid concentration curve was investigated. The influence of the uricase activity on the maximum rate of uric acid oxidation was also examined. The use of the NCP reagent demonstrated a more precise and more sensitive determination of the uric acid compared to the determination with 4-aminoantipyrine (4-AA) as the coupling regent. The sensitivity of the method determined from the calibration curve was 0.71 absorbance units per mmol/L of uric acid; the limit of detection was LOD = 0.0035 mmol/L and the limit of quantification was LOQ = 0.015 mmol/L of uric acid.

scholarly journals Reusable, Noninvasive, and Sensitive Fluorescence Enhanced ZnO-Nanorod-Based Microarrays for Quantitative Detection of AFP in Human Serum

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Saima Rafique ◽  
Farukh Kiyani ◽  
Sumbal Jawaid ◽  
Rubina Nasir ◽  
Mahmoosh Ahmad ◽  
...  
Keyword(s):  
Human Serum ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Zno Nanorods ◽  
Protein Microarrays ◽  
Great Promise ◽  
Quantitative Detection ◽  
Zno Nanorod ◽  
Serum Samples ◽  
Protein Assay

The fabrication of sensitive protein microarrays such as PCR used in DNA microarray is challenging due to lack of signal amplification. The development of microarrays is utilized to improve the sensitivity and limitations of detection towards primal cancer detection. The sensitivity is enhanced by the use of ZnO-nanorods and is investigated as a substrate which enhance the florescent signal to diagnose the hepatocellular carcinoma (HCC) at early stages. The substrate for deposition of ZnO-nanorods is prepared by the conventional chemical bath deposition method. The resultant highly dense ZnO-nanorods enhance the fluorescent signal 7.2 times as compared to the substrate without ZnO-nanorods. The microarray showed sensitivity of 1504.7 ng ml-1 and limit of detection of 0.1 pg ml-1 in wide dynamic range of 0.05 pg-10 μg ml-1 for alpha fetoprotein (AFP) detection in 10% human serum. This immunoassay was successfully applied for human serum samples to detect tumor marker with good recoveries. The ZnO-nanorod substrate is a simple protein microarray which showed a great promise for developing a low-cost, sensitive, and high-throughput protein assay platform for several applications in both fundamental research and clinical diagnosis.

scholarly journals Validation and Optimization of a Simple RP-HPLC Method for the Determination of Paracetamol in Human Serum and its Application in a Pharmacokinetic Study with Healthy Bangladeshi Male Volunteers

2015 ◽  
Vol 13 (2) ◽  
pp. 125-131
Author(s):  
Anisa Alam Tanam ◽  
Mohammad Firoz Khan ◽  
Ridwan Bin Rashid ◽  
Md Zakir Sultan ◽  
Mohammad A Rashid
Keyword(s):  
Human Serum ◽  
Pharmacokinetic Study ◽  
Internal Standard ◽  
Immediate Release ◽  
Hplc Method ◽  
Serum Samples ◽  
Limit Of Quantification ◽  
Rp Hplc ◽  
Relative Standard

Acetaminophen (paracetamol) is an analgesic and antipyretic agent with minimum anti-inflammatory properties. In the present study a simple, fast, accurate, precise and reproducible RP-HPLC method has been developed and validated for the quantification of paracetamol in human serum samples using theophylline as internal standard. Protein precipitation with perchloric acid was employed in the extraction of paracetamol and theophylline from biological matrix. The chromatographic separation was accomplished on Phenomenex C18 column with a mobile phase comprising of 0.05 mM sodium sulfate buffer (pH 2.2 ± 0.02 adjusted with phosphoric acid) and acetonitrile at a ratio of 93:7 at a flow rate of 1.0 ml/min. The chromatogram was monitored by UV detection at a wavelength of 254 nm. The method was validated over a linear concentration range of 2-100 ?g/ml and limit of quantification (LOQ) was 1.61 ?g/ml with a correlation coefficient (r2) 0.997. The intra-day and inter-day precision expressed as relative standard deviation were found to be 0.49 - 2.68% and 0.36 - 3.44%, respectively. The average recovery of paracetamol from serum ranged from 99.0 - 106.4%. The method was successfully applied to a pharmacokinetic study after oral administration of immediate release paracetamol tablet (1000 mg) in four healthy Bangladeshi volunteers. The mean Cmax was found to be 11.03 ± 3.21 ?g/ml, which occurred at Tmax of 0.88 ± 0.14 hr. The half life, AUC0-8 and AUC0-? values were found to be 3.09 ± 0.71 hr, 31.06 ± 6.57 hr-?g/ml and 37.92 ± 9.51 hr- ?g/ml, respectively. DOI: http://dx.doi.org/10.3329/dujps.v13i2.21889 Dhaka Univ. J. Pharm. Sci. 13(2): 125-131, 2014 (December)

scholarly journals Determination of cholesterol in human serum by an enzymatic method with the application of daos reagent

2000 ◽  
Vol 65 (7) ◽  
pp. 473-479
Author(s):  
Milena Jelikic-Stankov ◽  
Dejan Stankov ◽  
Snezana Paunovic
Keyword(s):  
Clinical Practice ◽  
Human Serum ◽  
Free Cholesterol ◽  
Limit Of Detection ◽  
Enzymatic Method ◽  
Limit Of Quantification ◽  
Experimental Conditions ◽  
Relative Standard ◽  
Influence Of Ph

A sensitive and specific enzymatic method has been developed for the determination of the total and free cholesterol in human serum based on the application of the newly-synthesized N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethoxyaniline, (DAOS) Trinder's reagent. Using the proposed method, cholesterol could be determined in the concentration range of 0.15 mmol/L with a relative standard deviation of up to 1.1%. In order to find the optimal experimental conditions for the application of the DAOS reagent, the influence of its concentration on the linearity of the method, the influence of pH, as well as the influence of the activities of cholesterolesterase and cholesteroloxidase were examined. The obtained results of the determination of the total and free cholesterol were compared to the results obtained by the application of the most frequently employed enzymatic method in clinical practice, based on phenol as a reagent. The sensitivity of the method was 0.070 A/mmol/L, the limit of detection DL=0.03 mmol/L and the limit of quantification QL=0.09 mmol/L of cholesterol.

scholarly journals Determination of Ethanol Content in Kombucha Using Headspace Gas Chromatography with Mass Spectrometry Detection: Single-Laboratory Validation

2020 ◽  
Author(s):  
Michael Chan ◽  
Hong Sy ◽  
Jamie Finley ◽  
Jake Robertson ◽  
Paula N Brown
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Alcoholic Beverage ◽  
The United States ◽  
Limit Of Quantification ◽  
Method Performance ◽  
Potential Health ◽  
Headspace Gas ◽  
Gas Chromatographic Method

Abstract Background Kombucha is a fermented beverage made with tea, sugar, and a symbiotic colony of bacteria and yeast that is usually marketed as a non-alcoholic beverage. Products must contain <0.5% and <1.1% alcohol by volume in the United States and Canada respectively to be classified as non-alcoholic products. Prior studies have found that Kombucha beverages can become very acidic and may contain levels of alcohol above 1% which can be a potential health risk to children and the developing fetus during pregnancy. Objective Given the public safety concerns and legal requirements associated with the level of alcohol within Kombucha beverages, there is a need for accurate and reliable methods. Herein we describe the validation of a sensitive, rapid, and simple Headspace Gas Chromatographic method with mass spectrometric detection for determining ethanol in Kombucha. Methods Method performance characteristics measured included linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ) as per AOAC International guideline Appendix K Part 1. Performance was evaluated against the AOAC Standard Method Performance Requirements 2016.001 for determination of ethanol in Kombucha. Results The linear dynamic range for this method was confirmed over the range of 0.025 to 2.47% ABV. The LOD and LOQ were determined to be 0.0002% and 0.002% ABV, respectively. With a spike recovery of 102% for accuracy and precision of RSDr ≤ 4% the method met the SMPR requirements within the analytical range. Conclusions The results of this validation study demonstrated the method is fit for the purpose of quantifying ethanol in Kombucha and is suitable for rapid and easy integration by laboratories to ensure that regulatory requirements are met.

Spectrophotometeric Determination of Trifluoperazine HCL in Pure Forms and Pharmaceutical Preperations

2017 ◽  
Vol 9 (5) ◽  
Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi
Keyword(s):  
Standard Method ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Oxidizing Agent ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Cerium Ion ◽  
Blank Solution

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.

Calcium/Copper alginate framework doped with CuO nano-particles as a novel adsorbent for micro-extraction of benzodiazepines from human serum

2020 ◽  
Vol 16 ◽  
Author(s):  
Nadereh Rahbar ◽  
Fatemeh Ahmadi ◽  
Zahra Ramezani ◽  
Masoumeh Nourani
Keyword(s):  
Human Serum ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Nano Particles ◽  
Limit Of Quantification ◽  
Analytical Methodology ◽  
Fiber Fabrication ◽  
Relative Standard ◽  
Green Procedure

Background: Sample preparation is one of the most challenging phases in pharmaceutical analysis, especially in biological matrices, affecting the whole analytical methodology. Objective: In this study, a new Ca(II)/Cu(II)/alginate/CuO nanoparticles hydrogel fiber (CCACHF) was synthesized through a simple, green procedure and applied for fiber micro solid phase extraction (FMSPE) of diazepam (DIZ) and oxazepam (OXZ) as model drugs prior to high-performance liquid chromatography-UV detection (HPLC-UV). Methods: Composition and morphology of the prepared fiber were characterized and the effect of main parameters on the fiber fabrication and extraction efficiency have been studied and optimized. Results: In optimal conditions, calibration curves were linear ranging between 0.1–500 µg L−1 with regression coefficients of 0.9938 and 0.9968. Limit of detection (LOD) (S/N=3) and limit of quantification (LOQ) (S/N=10) of the technique for DIZ and OXZ were 0.03 to 0.1 µg L−1. Within-day and between-day relative standard deviations (RSDs) for DIZ and OXZ were 6.0–12.5% and 3.3–9.4%, respectively. Conclusion: The fabricated adsorbent has been substantially employed to extraction of selected benzo-diazepines (BZDs) from human serum real specimens and the obtained recoveries were also satisfactory (82.1-109.7%).

Simultaneous Determination of Chloroquine and Pyrimethamine with Cetirizine in an Active Form and Human Serum by RP-HPLC

2021 ◽  
Author(s):  
Hina Shamshad ◽  
Ali Sayqal ◽  
Jahan Zeb ◽  
Agha Zeeshan Mirza
Keyword(s):  
Human Serum ◽  
Simultaneous Determination ◽  
Active Form ◽  
Internal Standard ◽  
Hplc Method ◽  
Serum Samples ◽  
Rp Hplc ◽  
Cetirizine Hydrochloride ◽  
Bulk Drug

Abstract A simple, accurate and precise RP-HPLC method was developed for the simultaneous determination of chloroquine, pyrimethamine and cetirizine hydrochloride concentrations in bulk drug and human serum. The assay was performed using a mobile phase of methanol: water (70:30) at pH of 2.8 ± 0.05 on the Purospher C-18 column with UV detection at 230 nm and rosuvastatin used as an internal standard. The retention times observed for chloroquine, pyrimethamine and cetirizine hydrochloride were 3.5, 2.5 and 5.5 minutes, respectively. The method was found to be specific for the assayed drugs showing a linear response in the concentration range of 1–100 μg mL−1 with coefficients of determination values of (r = 0.999). The method was developed and validated according to ICH guidelines. The method was used to monitor the serum samples and was found to be sensitive for therapeutic purposes, showing the potential to be a useful tool for routine analysis in laboratories.

scholarly journals A novel LC-MS method development and validation for the determination of phenyl vinyl sulfone in eletriptan hydrobromide

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Indhu Priya Mabbu ◽  
G. Sumathi ◽  
N. Devanna
Keyword(s):  
Method Development ◽  
Limit Of Detection ◽  
Vinyl Sulfone ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Development And Validation ◽  
Phenyl Vinyl

Abstract Background The aim of the present method is to develop and validate a specific, sensitive, precise, and accurate liquid chromatography-mass spectrometry (LC-MS) method for the estimation of the phenyl vinyl sulfone in the eletriptan hydrobromide. The effective separation of the phenyl vinyl sulfone was achieved by the Symmetry C18 (50 × 4.6 mm, 3.5 μm) column and a mobile phase composition of 0.1%v/v ammonia buffer to methanol (5:95 v/v), using 0.45 ml/min flow rate and 20 μl of injection volume, with methanol used as diluent. The phenyl vinyl sulfone was monitored on atomic pressure chemical ionization mode mass spectrometer with positive polarity mode. Results The retention time of phenyl vinyl sulfone was found at 2.13 min. The limit of detection (LOD) and limit of quantification (LOQ) were observed at 1.43 ppm and 4.77 ppm concentration respectively; the linear range was found in the concentration ranges from 4.77 to 27.00 ppm with regression coefficient of 0.9990 and accuracy in the range of 97.50–102.10%. The percentage relative standard deviation (% RSD) for six replicates said to be injections were less than 10%. Conclusion The proposed method was validated successfully as per ICH guidelines. Hence, this is employed for the determination of phenyl vinyl sulfone in the eletriptan hydrobromide.

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