The Coulometric Determination of Glucose in Human Serum

1968 ◽  
Vol 14 (5) ◽  
pp. 463-476 ◽  
Author(s):  
Robert K Simon ◽  
Gary D Christian ◽  
William C Purdy
Keyword(s):  
Human Serum ◽  
Glucose Oxidase ◽  
Coulometric Titration ◽  
Aerobic Oxidation ◽  
Enzymatic Reaction ◽  
Complete Recovery ◽  
Serum Levels ◽  
Normal Serum ◽  
Coulometric Determination

Abstract The coulometric titration method is combined with the use of an enzymatic analytic reagent for the determination of glucose in human serum. The glucose in 25 µl. of serum is determined in a protein-free filtrate (PFF) with an accuracy of ± 3% and a coefficient of variation of approximately 2%. The procedure routinely covers a concentration range of 25-250 mg/100 ml. Calibrations are linear to at least 450 mg./100 ml. with zero intercept. Glucose oxidase specifically catalyzes the aerobic oxidation of glucose to hydrogen peroxide. The peroxide reacts with iodide, in the presence of molybdenum (VI) catalyst, to form iodine. A known excess of thiosulfate reduces the iodine as it is produced. The reagents and the sample are incubated at 25.0° and pH 5.1. After 15 min., the pH is adjusted to 8.0 with phosphate reagent to stop the enzymatic reaction. The residual thiosulfate is titrated coulometrically with iodine at pH 8.0 to a dead-stop end point at a generating current of 0.4825 ma. The difference between the sample and thiosulfate reagent titers is proportional to the glucose concentration. The method is empirical. Peroxide-reducing impurities in the glucose oxidase preparation and mutarotation equilibrium prevent the complete recovery of glucose under the conditions of the experiment. Calibrations are reproducible from day to day and week to week. Reagents and the PFF constitute a negligible titration blank. Only 1 calculation is necessary. A simplified apparatus and procedure for the preparation of PFF’s permits 15 manual determinations per hour. Coulometric assays of commercial serum controls are accurate to within 3-4%. Data indicate that the precision of the coulometric method exceeds that of the Auto-Analyzer, Folin-Wu, Glucostat, and Nelson-Somogyi procedures. The proposed method is free from interferences at normal serum levels.

Determination of glucose in human serum based on an onion primary cuticula biosensor immobilized glucose oxidase

2012 ◽  
Vol 4 (5) ◽  
pp. 1432 ◽  
Author(s):  
Wenjuan Jia ◽  
Wenjuan Liu ◽  
Yan Zhang ◽  
Miao Cui ◽  
Shaomin Shuang ◽  
...  
Keyword(s):  
Human Serum ◽  
Glucose Oxidase ◽  
Immobilized Glucose Oxidase

scholarly journals Differential expression of an equivalent clonotype among BALB/c and C57BL/6 mice

1978 ◽  
Vol 147 (1) ◽  
pp. 1-12 ◽  
Author(s):  
MP Cancro ◽  
NH Sigal ◽  
NR Klinman
Keyword(s):  
Serum Levels ◽  
Inbred Strains ◽  
Cross Reactivity ◽  
Normal Serum ◽  
Cell Populations ◽  
Myeloma Protein ◽  
Regulatory Processes ◽  
Histocompatibility Complex ◽  
Immunoglobulin Allotype

The primary anti-phosphorylcholine (PC) response in BALB/c, C57BL/6, and congenic and recombinant inbred strains of these parental types has been examined in the splenic focus system. The frequencies of PC-specific precursors were shown to vary among these strains from 2 to 20 precursors per 10(6) splenic B cells. The distribution of these frequencies suggests that elements closely linked to or within the major histocompatibility complex may play a role in the determination of this parameter, although additional experiments are necessary to adequately assess this possibility. Moreover, all strains tested, regardless of immunoglobulin allotype, expressed monoclonal antibodies indistinguishable from the TEPC 15 myeloma protein (T15) clonotype. Further, the frequency of this clonotype in a given strain did not appear related to allotype, since both high and low T15 frequencies were found among strains of either the BALB/c (a(1)) or C57BL/6 (a(2)) allotype. The examination of normal serum for the T15 idiotype, however, revealed that only mice of the BALB/c allotype (a(1)) expressed the T15 idiotype in detectable quantities. After immunization with Diplococcus pneumoniae, sera from mice of the a(1) allotype consistently contained large quantities of the T15 idiotype, whereas sera from mice of the a(2) allotype exhibited various degrees of cross-reactivity with anti-T15 antibody. These results suggest that: (a) the allotype of an individual, although closely related to serum levels of an idiotype, is unrelated to the proportion of the precursor population which expresses that idiotype and; (b) the serum expression of a given idiotype may reflect regulatory processes, which act either during or before antigenic stimulation, rather than the actual clonotype representation in the repertoire. These findings indicate that distinctions must be made between the expression of idiotypic determinants within precursor B-cell populations and elements which regulate the subsequent appearance of those idiotypes in serum antibodies.

Nature of Materials in Serum That Interfere in the Glucose Oxidase—Peroxidase—o-Dianisidine Method for Glucose, and Their Mode of Action

1975 ◽  
Vol 21 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Walter J Blaedel ◽  
James M Uhl
Keyword(s):  
Molecular Weight ◽  
Uric Acid ◽  
Glucose Oxidase ◽  
Weight Fraction ◽  
Serum Glucose ◽  
Normal Serum ◽  
High Molecular Weight Fraction ◽  
Oxidase Reaction ◽  
Formation Step

Abstract Separation of blood serum on Sephadex G-100 reveals three fractions that interfere with the glucose oxidase— peroxidase method for serum glucose when o-dianisidine is used as the chromogen. A low-molecular-weight fraction containing primarily uric acid, a fraction containing protein with a molecular weight of about 40 000, and a fraction of even higher molecular weight (∼ 500 000) each interfered with glucose recovery when glucose was measured by this procedure. The uric acid fraction and the isolated 40 000 molecular weight fraction interfere by competing with o-dianisidine for hydrogen peroxide in the peroxidase-catalyzed color-formation step. The high-molecular-weight fraction not only interferes with the peroxidase reaction, but also with the glucose oxidase reaction itself. These agents cause values to be low by as much as 20% in the manual determination of glucose in normal serum if their interference is not recognized.

scholarly journals Determination of Polyhexamethylene Biguanide Utilizing a Glucose Oxidase Enzymatic Reaction

2019 ◽  
Vol 35 (9) ◽  
pp. 1021-1025 ◽  
Author(s):  
Kohei UEMATSU ◽  
Akihito SHINOZAKI ◽  
Hajime KATANO
Keyword(s):  
Glucose Oxidase ◽  
Enzymatic Reaction ◽  
Polyhexamethylene Biguanide

scholarly journals Multicommuted flow system for the determination of glucose in animal blood serum exploiting enzymatic reaction and chemiluminescence detection

2003 ◽  
Vol 25 (5) ◽  
pp. 109-114 ◽  
Author(s):  
Cherrine K. Pires ◽  
Patrícia B. Martelli ◽  
Boaventura F. Reis ◽  
José L. F. C. Lima ◽  
Maria Lúcia M. F. S. Saraiva
Keyword(s):  
Blood Serum ◽  
Glucose Oxidase ◽  
Confidence Level ◽  
Sampling Rate ◽  
Enzymatic Reaction ◽  
Porous Silica ◽  
Previous Treatment ◽  
Chemiluminescence Detection ◽  
Animal Blood

An automatic flow procedure based on multicommutation dedicated for the determination of glucose in animal blood serum using glucose oxidase with chemiluminescence detection is described. The flow manifold consisted of a set of three-way solenoid valves assembled to implement multicommutation. A microcomputer furnished with an electronic interface and software written in Quick BASIC 4.5 controlled the manifold and performed data acquisition. Glucose oxidase was immobilized on porous silica beads (glass aminopropyl) and packed in a minicolumn (15 } 5 mm). The procedure was based on the enzymatic degradation of glucose, producing hydrogen peroxide, which oxidized luminol in the presence of hexacyanoferrate(III), causing the chemiluminescence. The system was tested by analysing a set of serum animal samples without previous treatment. Results were in agreement with those obtained with the conventional method (LABTEST Kit) at the 95% confidence level. The detection limit and variation coefficient were estimated as 12.0 mg l−1(99.7% confidence level) and 3.5% (n=20), respectively. The sampling rate was about 60 determinations h−1with sample concentrations ranging from 50 to 600 mg l−1glucose. The consumptions of serum sample, hexacyanoferrate(III) and luminol were 46 μl, 10.0 mg and 0.2 mg/determination, respectively.

scholarly journals Determination of phenolic compounds in medicinal preparations by galvanostatic coulometry

2021 ◽  
Vol 8 (1) ◽  
pp. 20218110
Author(s):  
N. N. Yaschenko ◽  
S. V. Zhitar ◽  
E. G. Zinovjeva
Keyword(s):  
Phenolic Compounds ◽  
Coulometric Titration ◽  
Experimental Studies ◽  
Coulometric Determination ◽  
Correct Definition ◽  
Galvanostatic Coulometry ◽  
Coulometric Method ◽  
Preliminary Separation ◽  
Ascorbic Acids

In this work, the possibility of using reactions of electrogenerated titrants with phenolic compounds was studied and a method for their coulometric determination in medicaments by galvanostatic coulometry was developed. The research objects were: rutin, salicylic acid and drugs containing phenolic compounds such as «Ascorutin», «Salicylic Paste» and «Salicylic Ointment» of Russian manufacture. Electrogenerated halogens (Cl2, Br2 and I2) and hexacyanoferrate(III)-ions were used as titrants. It was found that for the quantitative determination of phenolic acids, the optimal reagent is electrogenerated bromine, for rutin - electrogenerated bromine and iodine, and for ascorbic acid - any of the studied electrogenerated titrants (Cl2, Br2, I2 and [Fe(CN)6]3-). The correct definition was checked by the «entered-found» method, the error does not exceed 2%. As experimental studies have shown, our method of coulometric titration with electrogenated bromine and iodine is characterized by good reproducibility of results, expression, accuracy and can be used to determine phenolic compounds in drugs, for example, «Ascorutin» tablets. It should be noted that by our procedure it is possible to determine the spectrum of phenol-containing compounds (rutin, ascorbic and salicylic acids) in drugs without their preliminary separation. Therefore, the coulometric method using electrogenerated titrants can be recommended for the determination of salicylic, ascorbic acids and rutin in dosage forms. The proposed method is accurate and eliminates the experiment error in comparison with the Pharmacopoeic method.

scholarly journals Determination of low chlorine content in organic compounds and polymers using an «Expert-006» coulometer

2018 ◽  
Vol 84 (7) ◽  
pp. 16-20
Author(s):  
D. Kh. Kitaeva ◽  
A. G. Buyanovskaya ◽  
O. A. Levinskaya ◽  
S. L. Dzvonkovski
Keyword(s):  
Coulometric Titration ◽  
Silver Ions ◽  
Electrolytic Cell ◽  
Chloride Ions ◽  
Chlorine Content ◽  
Residual Chlorine ◽  
Coulometric Determination ◽  
Electrochemical Parameters ◽  
Organic Matrices

A method of visual mercurimetric titration of chloride ions is widely used in elemental microanalysis for determination of chlorine content in organic substances after their combustion in an oxygen-filled flask. However, when chlorine content is less than 0.5%, the mercurimetric method fails to provide essential accuracy, and a more sensitive method of chlorine coulometric titration by electrogenerated silver ions appeared favorable. We consider a possibility of determining the microgram content of chloride-ions in solutions using a digital coulometric analyzer («Expert-006» produced by «Econics-Expert» (Moscow)) supplemented with an electrolytic cell with silver electrodes. The coulometer was tested in different operation modes to select the optimal electrochemical parameters of ion chloride titration and develop a technique for coulometric determination of chloride ions which in combination with the preliminary burning of the analyzed substances in an oxygen-filled flask provides determination of the residual chlorine in organic matrices at a level of 0.1 – 0.5%. The proposed technique was used to determine the residual chlorine in a number of polymers. The relative error did not exceed 5% at chlorine concentrations of 0.16 – 0.28%.

scholarly journals Dyskinesia induced by phenytoin

1999 ◽  
Vol 57 (2B) ◽  
pp. 356-360 ◽  
Author(s):  
M. AUGUSTA MONTENEGRO ◽  
ANNA ELISA SCOTONI ◽  
FERNANDO CENDES
Keyword(s):  
Side Effects ◽  
Side Effect ◽  
Clinical Characteristics ◽  
Complete Recovery ◽  
Serum Levels ◽  
Normal Serum ◽  
Pediatric Epilepsy ◽  
Orofacial Dyskinesia ◽  
Involuntary Movements ◽  
One Year

Phenytoin is an effective antiepileptic drug, although, it can be associated with many side effects, including dyskinesia. OBJECTIVE: To describe the clinical characteristics of phenytoin induced dyskinesia. METHODS: We investigated the occurrence of involuntary movements in patients followed at our adult and pediatric epilepsy clinics during the period of one year. RESULTS: Three patients presented with phenytoin-induced dyskinesia: one adult with axial and orofacial dyskinesia, and two children with choreoathetosis. They did not have other signs of phenytoin intoxication and had complete recovery after phenytoin withdrawal. CONCLUSION: Phenytoin induced dyskinesia may occur during either chronic or initial treatment and with normal serum phenytoin levels. However, it occurs most often in patients on polytherapy, usually after increasing dosage and with toxic serum levels. Other signs of phenytoin intoxication may be present in these patients, but often the dyskinesia is the only side effect, which may delay the diagnosis and treatment. The clinical characteristics of the involuntary movements vary and may be focal or generalized, most often characterized by choreoathetosis and dyskinesias. These may last for hours, days or even years, but frequently disappear completely after phenytoin withdrawal.

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