What is Nelson Somogyi method?
The nelson-somogyi method is used to measure reducing sugar by using copper reagents and arsenolmolibdat. The working principle of somogyi-nelson is the amount of deposro oxide deposits that react with arsenomolibdate which is reduced to molybdine blue and the blue color is measured absorbance.
Which glucose analytical method require Arsenomolybdate as reagent?
A photometric method has been described for the estimation of glucose (or reduction equivalent) with copper reagents and an arsenomolybdate reagent. The optical density of the color developed is proportional to the glucose taken and is stable over long periods of time.
What is Nelson’s reagent?
Nelson’s reagent was evolved in a search for a colorimetric reagent that would give intense, stable and reproducible colors with reduced alkaline copper reagents.
How do you make Arsenomolybdate reagent?
Arsenomolybdate reagent: Dissolve 2.5 g ammonium molybdate in 45 mL water. Add 2.5 mL sulphuric acid and mix well. Then add 0.3 g disodium hydrogen arsenate dissolved in 25 mL water. Mix well and incubate at 37°C for 24–48 hours.
Which is a better method Folin Wu or Somogyi Nelson?
The new technique which has been compared to glucose oxidase method, Somogyi’s procedure and Folin-Wu method is easier and more accurate than the Somogyi’s original method, and gives blood glucose values almost identical with that obtained with glucose oxidase procedure.
How do you make Nelson’s reagent?
Nelson’s reagent
Arsenomolybadate reagent (Nelson’s reagent), 25g ammonium molybdate is dissolved in 450 ml of water and 21 ml of concentrated sulphuric acid is slowly added with stirring. Then 3 g of sodium hydrogen arsenate dissolved in 25 ml distilled water, is poured slowly with constant stirring.
What are the 2 categories of methods in glucose determination?
There are three basic approaches to the laboratory measurement of blood glucose concentration: reducing methods, condensation methods, and enzymatic methods.
Why is blue filter used in Folin Wu?
This enediol will reduce cupric ions to the precipitate of cuprous oxide. This oxide is dissolved and reacted by phosphomolybdic acid to form phosphomolybdenum blue which is blue in color. Constricted tubes (Folin-Wu tubes) are used to avoid reoxidation of cuprous oxide by atmospheric oxygen.
What is the principle of Folin Wu method?
PRINCIPLE. In this method, proteins in blood are precipitated with tungstic acid. The protein free filtrate containing glucose reduces cupric ions (Cu2+) to cuprous ions (Cu+) and forms cuprous oxide (Cu2O). Cuprous oxide then reduces phosphomolybdic acid to blue phosphomolybdous acid (Molybdenum blue).
What is DNS method?
The dinitrosalicylic acid (DNS) method gives a rapid and simple estimation of the extent of saccharification by measuring the total amount of reducing sugars in the hydrolysate.
Which method is best for glucose estimation?
Glucose in blood is the most frequent analyzed parameter in a clinical chemistry laboratory. In Armed Forces Laboratories, copper reduction method (Modified Folin Wu) is commonly used. Here we have compared this method as well as O-Toluidine and GOD-POD method with reference UV-Hexokinase method.
What is the role of boiling in Folin Wu?
The glucose present in the protein-free filtrate on boiling in an alkaline medium will be changed to enediol form. This enediol will reduce cupric ions to the precipitate of cuprous oxide. This oxide is dissolved and reacted by phosphomolybdic acid to form phosphomolybdenum blue which is blue in color.
What is the reagent used in Folin Wu method?
Phosphomolybdic Reagent (P.M.R.). -This reagent was also prepared as described by Folin and Wu (1920). Standard Glucose Solution.
Why Folin Wu method does not give true glucose level?
This method is old and not specific for glucose determination since other substances (e.g. fructose, lactose, and glutathione) also bring about a reduction. The blood glucose level when estimated by the Folin-Wu method is higher than true glucose.
What is the role of phosphomolybdic acid in Folin Wu method?
A phosphomolybdic acid solution, containing a little tungstate, used in the determination of glucose. It gives a blue colour with the copper (i) oxide produced when the sample containing glucose …
Why DNSA is light sensitive?
3,5-Dinitrosalicylic acid (DNS or DNSA, IUPAC name 2-hydroxy-3,5-dinitrobenzoic acid) is an aromatic compound that reacts with reducing sugars and other reducing molecules to form 3-amino-5-nitrosalicylic acid, which strongly absorbs light at 540 nm.
What are the two types of DNS?
There are three main kinds of DNS Servers — primary servers, secondary servers, and caching servers.
- Primary Server. The primary server is the authoritative server for the zone.
- Secondary Servers. Secondary servers are backup DNS Servers.
- Caching Servers.
What are the different methods of estimation of glucose?
Different methods based on the different properties of glucose are described for blood glucose estimation [2, 3, 4, 5, 6, 7, 8].
…
TABLE 2.
| Method | Molar ext coeff | Detection limit |
|---|---|---|
| Mod Folin Wu | 24000 M−1 cm−1 | 0.31 mg/dl |
| GOD-POD | 6600 M−1 cm−1 | 0.30 mg/dl |
| Hexokinase | 6800 M−1cm−1 | 0.29 mg/dl |
What is the absorbance maxima for glucose by Folin Wu method?
absorbance at 420 nm along Y-axis. 7. From the standard curve calculate the concentration of glucose in the given sample.
Which method is most accurate for blood glucose estimation?
In most hands, the glucose oxidase strip method is accurate and reliable. Since whole blood is used, the results tend to be slightly lower than simultaneous venous samples, but this is balanced by the fact that capillary blood has a higher glucose concentration than venous blood.
Why do we heat in DNS method?
By heating for 10 minutes at elevated temperature the alkaline mixture of reducing sugar with DNS, the intense red color developed will absorbe the most and the intensity of this color complex will hold a straight line relationship with the concentration of the reducing sugar within the standardized working range of …
Can we store DNS reagent?
The DNSA reagent, with or without added NaOH, should be stored at room temperature. It can be stored for at least 24 months. Note that the mixture without NaOH may separate into two layers; this does not affect its performance and once NaOH has been added, the mixture is stable.
What are the three 3 types of DNS queries?
3 types of DNS queries—recursive, iterative, and non-recursive.
What are the 3 types of DNS?
What are the sources of error in glucose determination?
Common sources of meter error include patient or methodology interferences, operator mistakes, environmental exposure, and device malfunction.