A novel procedure for stabilization of azide in biological samples and method for its determination (HS-GC-FID/FID)

AbstractSodium azide is an old poison with toxicity comparable to potassium cyanide. It would seem to be completely forgotten however, between 2000 and 2020, the number of intentional ingestions and murders committed with sodium azide significantly increased. Furthermore, due to its extreme instability, sodium azide is difficult to detect, which poses an additional risk when used to commit a crime. In this study, the epidemiology of sodium azide exposures between 1920 and 2020 was investigated. For the determination the azide concentration in biological samples, a simple, precise and selective headspace gas chromatography method (HS-GC-FID/FID) was developed and fully validated. The limit of quantification was 0.65 µg/mL; and the limit of detection was 0.35 µg/mL; precision and accuracy did not exceed 20%. The stability study was conducted for various biological fluids (urine, bile, blood, gastric content) for 91 days in the refrigerator (4 °C) and the method for stabilization of azide was presented. The addition of a mixture of borax and sodium fluoride (w/w 3:1) to the test tubes can stabilize this poison. The described unique technique of collecting the biological samples poses a great potential for azide detection in clinical and toxicology laboratories even long time after human exposure to this substance.

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Development and Validation of Stability Indicating Reverse Phase High Performace Liquid Chromatography Method for the Determination of Umeclidinium and Vilanterol in Pharmaceutical Dosage Form

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2021/v33i42a32398 ◽

2021 ◽

pp. 208-219

Author(s):

Ahsaana Hamsa ◽

K. Praseetha ◽

K. P. Dijin Raj ◽

T. V. Ashira ◽

O. V. Athira ◽

...

Keyword(s):

Liquid Chromatography ◽

Dosage Form ◽

Limit Of Detection ◽

Limit Of Quantification ◽

Chromatography Method ◽

Pharmaceutical Dosage Form ◽

Relative Standard ◽

Validation Parameters ◽

The Stability

A Sensitive, fast, linear and accurate liquid chromatography technique was developed for the simultaneous determination of Umeclidinium and Vilanterol in Powder dosage form. The estimation was carried out using Phenomenex C18 column (150 × 4.6 mm, 5μ) with ammonium acetate: acetonitrile taken in the ratio 60:40 as mobile phase and pumped at a flow rate of 0.9 ml/min at 300C. Detection wavelength selected was 245 nm. Retention times of Umeclidinium and Vilanterol were found to be 2.219 min and 2.794 min. The method was validated in terms of linearity, precision, accuracy, limit of detection, limit of quantification as per International council for harmonization guidelines. Degradation studies performed indicated the stability of the drug. All of these analytical validation parameters were evaluated, and the percent relative standard deviations were calculated, indicating the method's suitability for determination of Umeclidinium and Vilanterol in pharmaceutical dosage form.

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DETERMINATION OF 10-GINGEROL IN INDIAN GINGER BY VALIDATED HPTLC METHOD OF SAMPLES COLLECTED ACROSS SUBCONTINENT OF INDIA

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2016v8i12.14953 ◽

2016 ◽

Vol 8 (12) ◽

pp. 190

Author(s):

Kamran Ashraf ◽

Syed Adnan Ali Shah ◽

Mohd Mujeeb

Keyword(s):

Thin Layer ◽

Thin Layer Chromatography ◽

High Performance ◽

Limit Of Detection ◽

Limit Of Quantification ◽

Chromatography Method ◽

Aluminum Plates ◽

Layer Chromatography ◽

Hptlc Method

Objective: A simple, sensitive, precise, and accurate stability indicating HPTLC (high-performance thin-layer chromatography) method for analysis of 10-gingerol in ginger has been developed and validated as perICH guidelines.Methods: The separation was achieved on TLC (thin layer chromatography) aluminum plates pre-coated with silica gel 60F254 using n-hexane: ethyl acetate 55:45 (%, v/v) as a mobile phase. Densitometric analysis was performed at 569 nm.Results: This system was found to have a compact spot of 10-gingerol at RF value of 0.57±0.03. For the proposed procedure, linearity (r2 = 0.998±0.02), limit of detection (18ng/spot), limit of quantification (42 ng/spot), recovery (ranging from 98.35%–100.68%), were found to be satisfactory.Conclusion: Statistical analysis reveals that the content of 10-gingerol in different geographical region varied significantly. The highest and lowest concentration of 10-gingerol in ginger was found to be present in a sample of Patna, Lucknow and Surat respectively which inferred that the variety of ginger found in Patna, Lucknow are much superior to other regions of India.

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Surface-Enhanced Oxidation and Determination of Isothipendyl Hydrochloride at an Electrochemical Sensing Film Constructed by Multiwalled Carbon Nanotubes

International Journal of Electrochemistry ◽

10.1155/2012/875631 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6

Author(s):

S. N. Prashanth ◽

Shankara S. Kalanur ◽

Nagappa L. Teradal ◽

J. Seetharamappa

Keyword(s):

Limit Of Detection ◽

Biological Fluids ◽

Differential Pulse ◽

Electrochemical Sensing ◽

Good Precision ◽

Multiwalled Carbon ◽

Limit Of Quantification ◽

Surface Enhanced ◽

Ph Range

The electrochemical behavior of isothipendyl hydrochloride (IPH) was investigated at bare and multiwalled-carbon-nanotube modified glassy carbon electrode (MWCNT-GCE). IPH (55 μM) showed two oxidation peaks in Britton-Robinson (BR) buffer of pH 7.0. The oxidation process of IPH was observed to be irreversible over the pH range of 2.5–9.0. The influence of pH, scan rate, and concentration of the drug on anodic peak was studied. A differential pulse voltammetric method with good precision and accuracy was developed for the determination of IPH in pure and biological fluids. The peak current was found to be linearly dependent on the concentration of IPH in the range of 1.25–55 μM. The values of limit of detection and limit of quantification were noticed to be 0.284 and 0.949 μM, respectively.

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THE DEVELOPMENT OF A METHOD FOR DIRECT MASS SPECTROMETRIC ANALYSIS OF BIOLOGICAL SAMPLES USING POROUS SAMPLERS

Aerospace and Environmental Medicine ◽

10.21687/0233-528x-2021-55-1-99-103 ◽

2021 ◽

Vol 55 (1) ◽

pp. 99-103

Author(s):

R.E. Levin ◽

◽

M.A. Shamraeva ◽

I.M. Larina ◽

D.S. Bormotov ◽

...

Keyword(s):

Biological Samples ◽

Biological Fluids ◽

Storage Conditions ◽

Spectrometric Analysis ◽

Sample Collection ◽

Mucous Membranes ◽

The Status ◽

Direct Mass Spectrometry ◽

The Stability ◽

Blood Spot

The paper presents a method for rapid multi-omics investigation of biological samples using polypropylene bulk porous samplers. The use of porous samplers makes it easy to collect samples from the surface of the skin, mucous membranes, and biological fluids even in a field, and the surfaces of wounds and injuries. Collected samples do not require special storage conditions, and the samplers are lightweight and very compact. They can be used to monitor the condition of cosmonauts before, during, and after the spaceflight with the same sample collection method. The analysis of biomaterial applied to the sampler is performed using direct mass spectrometry methods, similar to the dried blood spot technique that is already used in clinical practice. However, bulk porous samplers allow expanding the range of analytes ionization conditions, which increases the stability and reliability of the ionization process, which expands the variety of analyzed molecules. The proposed method can be used to study compounds of various classes, including proteins, lipids, and metabolites, to systematically monitor the status of people in extreme conditions (athletes, astronauts), or to study the condition of patients in the clinic.

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Serological biomarkers of zearalenone exposure in beef heifers receiving anti-mycotoxin additive

World Mycotoxin Journal ◽

10.3920/wmj2019.2548 ◽

2020 ◽

pp. 1-10

Author(s):

C. Tonini ◽

M.S. Oliveira ◽

E.B. Parmeggiani ◽

D.A.F. Sturza ◽

A.O. Mallmann ◽

...

Keyword(s):

Limit Of Detection ◽

Biological Fluids ◽

Basal Diet ◽

Beef Heifers ◽

Efficacy Evaluation ◽

Limit Of Quantification ◽

In Vivo Measurement ◽

Significant Difference ◽

Serological Biomarkers

The inclusion of anti-mycotoxin additives (AMA) in the diet of production animals has been widely used to avoid mycotoxin exposure. In order to confirm the efficacy of such products in vivo, measurement of mycotoxins and/or their metabolites in biological fluids is preconized. This study aimed at determining the serological biomarkers of zearalenone (ZEN), α-zearalenol, β-zearalenol, α-zearalanol, β-zearalanol (β-ZAL) and zearalanone, to evaluate the efficacy of an AMA in beef heifers. The trial lasted 37 days: 11 days of adaptation, 21 days of actual experiment, and 5 days of regression. Twenty-four heifers were randomly assigned to receive one of the following treatments (n=6/group): (T1) basal diet (control); (T2) basal diet + 5 mg/kg of ZEN; (T3) basal diet + 5 mg/kg of ZEN + 2.5 kg/t of AMA; and (T4) basal diet + 5 mg/kg of ZEN + 5.0 kg/t of AMA. Blood sampling was performed on different days after the diet was given. The samples were centrifuged to obtain the blood serum, and then analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). β-ZAL was detected above the limit of quantification both in the unconjugated (>0.60 ng/ml) and conjugated (>0.90 ng/ml) forms. The remaining metabolites presented concentrations under the limit of detection. In the efficacy evaluation of the AMA, there was no significant difference (P>0.05) between the treatments with and without additive at the tested levels of inclusion. Thus, β-ZAL may be employed as a biomarker of ZEN exposure via diet to evaluate the efficacy of an AMA through serological parameters. The technique applied in this study proved to be an adequate alternative for in vivo confirmation of the efficacy of products in adsorbing the toxin.

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Oxytetracycline Residues in Honey Analyzed by Liquid Chromatography with UV Detection

Journal of Apicultural Science ◽

10.2478/jas-2013-0003 ◽

2013 ◽

Vol 57 (1) ◽

pp. 25-32 ◽

Cited By ~ 1

Author(s):

Anna Gajda ◽

Andrzej Posyniak ◽

Andrzej Bober ◽

Tomasz Błądek ◽

Jan Żmudzki

Keyword(s):

Liquid Chromatography ◽

Oxalic Acid ◽

Limit Of Detection ◽

Solid Phase ◽

Experimental Treatment ◽

Uv Detection ◽

Limit Of Quantification ◽

Chromatography Method ◽

Liquid Chromatography Method

Summary A liquid chromatography method with UV detection for determination of oxytetracycline (OTC) in honey has been developed. The samples were extracted with the solution of oxalic acid. The clean-up procedure was performed by solid phase extraction (SPE) using polymeric Strata X and carboxylic acid cartridges. Chromatographic separation was carried out on the Luna C8 analytical column with mobile phase consisting of acetonitrile-0.02 M oxalic acid. The method has been successfully validated according to the requirements of the European Decision 2002/657/EC and this method is used in routine control of oxytetracycline in honey samples. The limit of detection (LOD) and limit of quantification (LOQ) of the presented method were 10 and 12.5 μg/kg, respectively. The developed method has also been verified in quantitative determination of oxytetracycline residues in honey after experimental treatment with this product in bee colonies.

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A Fast and Validated HPLC Method for Simultaneous Determination of Dopamine, Dobutamine, Phentolamine, Furosemide, and Aminophylline in Infusion Samples and Injection Formulations

Journal of Analytical Methods in Chemistry ◽

10.1155/2021/8821126 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Fuchao Chen ◽

Baoxia Fang ◽

Sicen Wang

Keyword(s):

Mobile Phase ◽

Dosage Form ◽

Limit Of Detection ◽

Hplc Method ◽

Stability Study ◽

Precision Data ◽

Column Temperature ◽

Ich Guidelines ◽

Limit Of Quantitation ◽

The Stability

A simple, fast, and validated HPLC method was developed for the simultaneous quantization of five cardiovascular agents: dopamine (DPM), dobutamine (DBM), phentolamine (PTM), furosemide (FSM), and aminophylline (APL) either in infusion samples or in an injection dosage form. The proposed method was achieved with a 150 mm × 4.6 mm, 5.0 μm C18 column, by using a simple linear gradient. Mobile phase A was buffer (50 mM KH2PO4) and mobile Phase B was acetonitrile at a flow rate of 1.0 mL/min. The column temperature was kept at 30°C, and the injection volume was 20 μL. All analytes were separated simultaneously at a retention time (tr) of 3.93, 5.84, 7.06, 8.76, and 9.67 min for DPM, DBM, PTM, FSM, and APL, respectively, with a total run time of less than 15.0 min. The proposed method was validated according to ICH guidelines with respect to accuracy, precision, linearity, limit of detection, limit of quantitation, and robustness. Linearity was obtained over a concentration range of 12.0–240.0, 12.0–240.0, 20.0–200.0, 6.0–240.0, and 10.0–200.0 μg/mL DPM, DBM, PTM, FSM, and APL, respectively. Interday and intraday accuracy and precision data were recorded in the acceptable limits. The new method has successfully been applied for quantification of all five drugs in their injection dosage form, infusion samples, and for evaluation of the stability of investigated drugs in mixtures for endovenous use. The results of the stability study showed that mixtures of DPM, DBM, PTM, FSM, and APL in 5% glucose or 0.9% sodium chloride injection were stable for 48 hours when stored in polypropylene syringes at 25°C.

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Simultaneous Estimation and Validation of Atorvastatin Calcium and Aspirin in Combined Capsule Dosage Form by RP HPLC Method

E-Journal of Chemistry ◽

10.1155/2012/789538 ◽

2012 ◽

Vol 9 (3) ◽

pp. 1449-1456

Author(s):

B. V. Suma ◽

K. Kannan ◽

V. Madhavan ◽

Chandini R. Nayar

Keyword(s):

Limit Of Detection ◽

Hplc Method ◽

Simultaneous Estimation ◽

Uv Detector ◽

Limit Of Quantification ◽

Chromatography Method ◽

Atorvastatin Calcium ◽

Ich Guidelines ◽

Phase Liquid ◽

Liquid Chromatography Method

A new simple, specific, precise and accurate revere phase liquid chromatography method has been developed for estimation of atorvastatin calcium (AST) and ASPIRIN (ASP) simultaneously in a combined capsule dosage forms. The chromatographic separation was achieved on a 5 – micron C 18 column (250x 4.6mm) using a mobile phase consisting of a mixture of Acetonitrile: Ammonium Acetate buffer 0.02M (68:32) pH 4.5. The flow rate was maintained at 0.8 ml/min. The detection of the constituents was done using UV detector at 245 nm for AST and ASP. The retention time of AST and ASP were found be 4.5915 ± 0.0031 min and 3.282 ±0.0024 min respectively. The developed method was validated for accuracy, linearity, precision, limit of detection (LOD) and limit of quantification (LOQ) and robustness as per the ICH guidelines.

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Stability-Indicating Photochemical Method for the Assay of Thiamine by Spectrophotometry

Journal of Spectroscopy ◽

10.1155/2018/3178518 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Iqbal Ahmad ◽

Syed Haider Abbas ◽

Zubair Anwar ◽

Muhammad Ali Sheraz ◽

Sofia Ahmed ◽

...

Keyword(s):

Limit Of Detection ◽

The United States ◽

Limit Of Quantification ◽

Chromatography Method ◽

Stability Indicating ◽

Low Concentrations ◽

Photochemical Method ◽

Significant Difference ◽

Liquid Chromatography Method ◽

States Pharmacopeia

A stability-indicating photochemical method has been developed for the assay of thiamine (TH) salts in aqueous solution and in fresh and aged vitamin preparations. It is based on the photooxidation of TH by UV irradiation to form thiochrome (TC) in alkaline solution. The TC : TH ratio under controlled conditions of light intensity, temperature, pH, exposure time, and irradiation distance is constant and can be used to determine the concentration of UV irradiated TH solutions. TC, on extraction with isobutanol from the photodegraded solution of TH, has been determined by the UV spectrophotometric method at 370 nm. It exhibits a high intensity of absorption in the UV region that can be used for the assay of even low concentrations of TH. Under optimum conditions, Beer’s law is obeyed in the concentration range of 0.20–2.00 mg/100 ml (R2 = 09998). The limit of detection (LOD) and limit of quantification (LOQ) are 0.0076 and 0.0231 mg/100 ml, respectively. The method has been validated and applied to aqueous solutions and vitamin preparations. The results have statistically been compared with the United States Pharmacopeia liquid chromatography method. It has been found that there is no significant difference between the two methods at 95% confidence level.

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Determination of Formaldehyde by HPLC with Stable Precolumn Derivatization in Egyptian Dairy Products

International Journal of Analytical Chemistry ◽

10.1155/2018/2757941 ◽

2018 ◽

Vol 2018 ◽

pp. 1-5 ◽

Cited By ~ 4

Author(s):

Ahmed Salem Sebaei ◽

Ahmed M. Gomaa ◽

A. A. El-Zwahry ◽

E. A. Emara

Keyword(s):

Dairy Products ◽

High Performance ◽

Limit Of Detection ◽

Precolumn Derivatization ◽

Limit Of Quantification ◽

Chromatography Method ◽

Derivatizing Agent ◽

Array Detection ◽

Liquid Chromatography Method

Formaldehyde is one of the most dangerous chemical compounds affecting the human health; exposure to it from food may occur naturally or by intentional addition. In this study a high performance liquid chromatography method for determination of formaldehyde in dairy products was described. The dairy samples were reacted and extracted with a warmed organic solvent in the presence of derivatizing agent 2,4-dinitrophenylhydrazine (DNPH) and formaldehyde; the mixture was centrifuged and followed by diode array detection. The method is validated and gives average recovery of formaldehyde at the three different levels 0.1, 5.0, and 10.0 mg/kg varied between 89% and 96%. The method is linear from the limit of quantification 0.1 mg/kg up to 10 mg/kg levels. This method is intended for formaldehyde analyses in dairy products simply with stable derivatization, minimum residue loss, excellent recovery, and accurate results with a sensitive limit of detection 0.01 mg/kg. 90 dairy samples from milk, cheese, and yogurt were investigated from seven Egyptian governorates and all samples were free from formaldehyde.

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