An Automated Fluorometric Method for Determination of Malate Dehydrogenase Activity in Serum

1970 ◽  
Vol 16 (7) ◽  
pp. 579-586 ◽  
Author(s):  
P L Schwartz ◽  
H J Burns
Keyword(s):  
Dehydrogenase Activity ◽  
Malate Dehydrogenase ◽  
Mean Value ◽  
Automated System ◽  
System Control ◽  
Automated Method ◽  
A Value ◽  
Control Serum ◽  
The Stability

Abstract An automated system for the sensitive, reproducible determination of malate dehydrogenase activity in serum is described and evaluated. After incubation of serum at 25°C and double dialysis, fluorometry is used to measure the disappearance of NADH during reaction. Certain precautions are necessary to maintain the stability of NADH and oxaloacetate and to assure washout of adsorbed serum components from the system. Control serum (Enza-trol) is used as an enzyme reference material. Results from the automated method agree well with those from an independent manual method. Replicability is excellent, and results from samples stored at 4° or -20°C are essentially the same as those from fresh samples. A mean value of 36.6 ± 8.5 U of malate dehydrogenase per liter was obtained on sera from 34 healthy adults, a value that agrees well with normal values obtained by others.

An Automated Detection System for Most L-α-Amino Acids

1969 ◽  
Vol 15 (2) ◽  
pp. 154-161 ◽  
Author(s):  
K Van Dyke ◽  
C Szustkiewicz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Detection System ◽  
Automated System ◽  
Acid Oxidase ◽  
Enzymatic Reactions ◽  
Amino Acid Oxidase ◽  
Automated Method ◽  
Wide Range

Abstract An automated system for the determination of the L-α form of the majority of amino acids is presented. The method is based upon oxidative deamination of the amino acid coupled with oxidation of o-dianisidine by hydrogen peroxide. This procedure can be used comparatively for the determination of a mixture of L-α-amino acids or for the majority of separated L-α-amino acids (especially in conjunction with column separations from urine and blood which give falsely positive identification with ninhydrin detection). The stereospecific nature of the L-α-amino acid oxidase enables the investigator to quantitate the amount of L-α-amino acid in the presence of the D-α form. From an academic viewpoint, the extreme sensitivity and wide range of the detection system make it advantageous for the study of the enzyme itself. This automated method also may be employed to follow enzymatic reactions—e.g., those catalyzed by peptidases or racemases. The methodology is extremely convenient with good reagent stability and is much more sensitive than manometric technics.

Automated Chemical Determination of Methionine

1974 ◽  
Vol 57 (3) ◽  
pp. 682-688
Author(s):  
Charles W Gehrke ◽  
Terry E Neuner
Keyword(s):  
Amino Acid ◽  
Standard Deviation ◽  
Ion Exchange ◽  
Automated System ◽  
Automated Method ◽  
Relative Standard ◽  
Chemical Determination ◽  
Sample Recovery ◽  
Hydrolysis Of

Abstract A rapid, accurate, and precise spectrophotometry method, based on the nitroprussidemethionine color reaction, has been developed for the determination of methionine in soybeans, mungbeans, and corn. Amino acid interference was eliminated by partial enzymatic hydrolysis of samples for 4 hr at 50 °C with papain; the samples were analyzed by an automated system. Precision and accuracy were determined by repeated independent analyses of 13 samples of corn, mungbeans, and soybeans; the data were compared to independent classical ion exchange amino acid results. The range for each set of samples varied from 0.02 to 0.04 w/w% methionine. The per cent recovery for 12 of the 13 samples compared to those from ion exchange ranged from 95.2 to 107.1% with an average of 100.2%. The standard deviation varied from 0.01 to 0.02, and the per cent relative standard deviation from 11.8% for a 0.16 w/w% sample to 2.5% for a 0.42 w/w% sample. Recovery of added methionine from corn samples ranged from 92.7 to 102.0% (96.8% average) ; from soybeans 95.0 to 112.0% (101.9% average); and from mungbeans 91.3 to 102.0% (95.8% average). A reliable automated method has been developed which is applicable to different types of biological substances; 20 samples/hr can be analyzed.

Automated Method for the Determination of Deuterium Oxide in Water and Biologic Fluids

1969 ◽  
Vol 15 (1) ◽  
pp. 56-60 ◽  
Author(s):  
R C Robbins
Keyword(s):  
Standard Deviation ◽  
Deuterium Oxide ◽  
Automated System ◽  
Automated Method ◽  
Infrared Spectrophotometer

Abstract An automated system has been assembled for determination of deuterium oxide in water and physiologic fluids. The system consists of an AutoAnalyzer sampler, proportioning pump, and dialyzer; a Perkin-Elmer infrared spectrophotometer; and a Sargent recorder. Reproducibility of peak heights showed a standard deviation of less than ± 1 mm. over a range of D2O concentrations from 0.125 to 1.000%.

Automated System for Monitoring and Diagnostics Pilot's Emotional State in Flight

2021 ◽  
Vol 14 (1) ◽  
pp. 1-16
Author(s):  
Tetiana Shmelova ◽  
Yuliya Sikirda ◽  
Arnold Sterenharz
Keyword(s):  
Emotional State ◽  
Emotional Experience ◽  
Automated System ◽  
Human Operator ◽  
Aviation Accidents ◽  
Nyquist Criterion ◽  
Actual Material ◽  
The Stability ◽  
Monitoring And Diagnostics

In this article, the system for monitoring of the emotional state changes of the air navigation system's human operator in the extreme situations, based on the using of the prior models of the operator activity which built on the posterior researches of actual material of the aviation accidents investigations, has been proposed. The stability of aviation man-machine system “human-operator – aircraft” during the deformations of the operator's emotional experience has been defined according to the Nyquist criterion. A computer program for diagnostics of the emotional state of the human operator has been developed. The system based on monitoring of the current emotional state of the air navigation system's human operator and diagnostics of the deformations of emotional experience with the determination of the operator's functional stability will allow preventing the development of potentially hazardous flight situations towards worsening in a proactive manner.

scholarly journals Study of the β-Cyclodextrin Imipramine Hydrochloride Inclusion Complex and Determination of its Stability Constant (K) by UV-Visible Spectroscopy

2007 ◽  
Vol 4 (4) ◽  
pp. 550-558 ◽  
Author(s):  
Alamdar Ashnagar ◽  
Nahid Gharib Naseri ◽  
Bita Khanaki
Keyword(s):  
Stability Constant ◽  
Inclusion Complex ◽  
Visible Spectroscopy ◽  
Constant Amount ◽  
A Value ◽  
Visible Spectra ◽  
Imipramine Hydrochloride ◽  
Uv Visible ◽  
The Stability

In this research, the interactions of imipramine hydrochloride drug with β- cyclodextrin and the stability constant (K) of the inclusion complex formed between them were investigated by using UV-visible spectroscopy. Solutions consisting of a known and constant amount of imipramine hydrochloride and varying amounts of β- cyclodextrin were prepared in 0.1 M phosphate buffer (pH 7.4). The final solutions had cyclodextrin concentrations between 0.0011 and 0.0153 M. UV-visible spectra of each solution was taken at λmax= 250 nm. The absorbances at this wavelength were recorded and plotted against cyclodextrin concentrations. From the graph, the concentrations of free and bound imipramine hydrochloride and free β-cyclodextrin were calculated using the Beer-Lambert law. From these data, the stability constant was calculated and a value of K=52.26±11.41 mol-1L was obtained. The magnitude of the stability constant is discussed in terms of the relative sizes and the chemical natures of β-cyclodextrin and imipramine hydrochloride.

Semiautornated Determination of Ormetoprim in Feeds

1974 ◽  
Vol 57 (1) ◽  
pp. 32-36
Author(s):  
Modest Osadca ◽  
Mercedes Araujo ◽  
Elmer De Ritter
Keyword(s):  
Nitrous Acid ◽  
Amyl Alcohol ◽  
Enzyme Digestion ◽  
Automated System ◽  
Fluorescence Measurement ◽  
Automated Method ◽  
Spectrofluorometric Method ◽  
Manual Extraction ◽  
Fluorescent Derivative

Abstract An automated spectrofluorometric method has been developed for determining ormetoprim in feeds at use levels of 0.0037-0.0075%. After manual extraction involving enzyme digestion, blending with alkali and chloroform, and cleanup of the extract by solvent transfers, the oxidation and fluorescence measurement steps are fully automated. The automated system includes oxidation with permanganate, removal of excess permanganate with nitrous acid and of excess nitrous acid with urea, acidification, extraction of the fluorescent derivative with hexane-tert-amyl alcohol, and fluorescence measurement in a spectrofluorometer with a recorder and printout. Recoveries of ormetoprim added to feeds are good, the fluorescence response is linear over a suitable working range, and blank values on unmedicated feeds are negligible. Twenty to thirty extracts per hr can be assayed by the automated method with increased precision over an allmanual operation.

scholarly journals An Automated Method for the Determination of Intestinal Disaccharidase and Glucoamylase Activities

2006 ◽  
Vol 2006 ◽  
pp. 1-4 ◽  
Author(s):  
Zhaoping He ◽  
Laura Bolling ◽  
Dalal Tonb ◽  
Tracey Nadal ◽  
Devendra I. Mehta
Keyword(s):  
Quality Control ◽  
Automated System ◽  
Internal Quality ◽  
Perfect Agreement ◽  
Manual Method ◽  
Automated Method ◽  
Reaction Volumes ◽  
High Consistency ◽  
Larger Sample

Determination of disaccharidase and glucoamylase activities is important for the diagnosis of intestinal diseases. We adapted a widely accepted manual method to an automated system that uses the same reagents reaction volumes, incubation times, and biopsy size as the manual method. A dye was added to the homogenates as the internal quality control to monitor the pipetting precision of the automated system. When the automated system was tested using human intestinal homogenates, the activities of all the routinely tested disaccharidases, including lactase, maltase, sucrase, and palatinase, as well as the activity of glucoamylase, showed perfect agreement with the manual method and were highly reproducible. The automated analyzer can perform the same routine assays of disaccharidases and glucoamylase with high consistency and accuracy and reduce testing costs by performing a larger sample size with the same number of staff. Additional developments, such as barcoding and built-in plate reading, would result in a completely automated system.

Collaborative Study of an Automated Method for the Determination of Nitrogen in Meat Products

1974 ◽  
Vol 57 (4) ◽  
pp. 838-840
Author(s):  
Walter M Gantenbein ◽  
Jon L Schermerhorn ◽  
Elmer George
Keyword(s):  
Room Temperature ◽  
Collaborative Study ◽  
Meat Products ◽  
Automated System ◽  
Average Standard Deviation ◽  
Colorimetric Measurement ◽  
Automated Method ◽  
Average Coefficient ◽  
Aoac Method

Abstract An automated method for nitrogen in meat products was studied collaboratively. Samples were solubilized in sulfuric acid (1 + 1) , cooled to room temperature, and presented to an automated system. Digestion, dilution, and colorimetric measurement of the nitrogen were performed automatically. Samples were also analyzed by the official final action AOAC method, 24.010. Eight collaborators representing 6 laboratories participated in the study. Each participant analyzed 9 different samples in duplicate. Results of the study were satisfactory with an average range of 0.5% protein, average standard deviation of ±0.21%, and average coefficient of variation of 1.20%. The method was found to be as accurate as 24.010 and applicable to meat and meat products containing 0.8–4.0% nitrogen (5.0–25% protein). It has been adopted as official first action.

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