Determining The Glucose Content Of And Orange Using GOD-PAP Essay Sample

Every fruit has a sweet gustatory sensation merely that some are sweeter than others. The sugariness of most fruits come from its sugar content and these sugars that the fruits contain are known as invert sugars. In this experiment. an orange was used. An orange which is an first-class beginning of vitamin C gets its sugariness from natural sugars which are sucrose. glucose and fruit sugar ( livestrong. com ) . In this experiment the concentration of glucose in an orange was measured. There are assorted methods which can be used to mensurate the glucose concentration but in this experiment a extremely specific enzymatic method utilizing the GOD-PAP check ( glucose oxidase peroxidase aminophenazone phenol ) ( schedule banishment. 2013 ) . This check is based on 2 conjugate enzyme reactions and a colorimetric end-point. D-glucose + O2 +H2O → H2O2 + gluconate aminophenazone + phenol + H2O2 → a ruddy dye + H2O2 Under stable conditions. optical density measured utilizing a spectrophotometer will be relative to the sum of glucose present ( schedule Coventry. 2013 ) .

Spectrophotometry is a method used to mensurate optical density of visible radiation. This measuring is carried out utilizing a spectrophotometer. A spectrophotometer is an equipment used to take accurate measuring of optical density at assorted wavelengths. Electrons are normally present at different energy degrees but are normally at land province ( stationary province ) which is the lowest energy degree. When negatrons are exposed to energy such as heat or visible radiation they become aroused. One quantum of energy is absorbed for an negatron to go aroused ( from land province to excited province ) and for it to travel back to its land province one quantum of energy is released.

There are two Torahs environing the optical density of visible radiation in a solution known as the Beer-lambert relationship. These Torahs province that the soaking up of visible radiation is exponentially related to the concentration of the solute. It besides states that the soaking up of visible radiation is exponentially related to the length of the light way through the engrossing solution. The Beer-lambert relationship is expressed as therefore: A=el [ C ] which refers to the algorithm of the ration of the incident visible radiation to the emergent visible radiation expressed as ( A=Log10 ( l0/l ) ) ( Reed et al. 2007 ) . The intent of this experiment was to find the unknown concentration of glucose utilizing the GOD-PAP check and a standardization curve. The measurings were taken utilizing a spectrophotometer.

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The experiment was carried out as par the research lab agenda ( Coventry university agenda. 2013 )

Table 1 shows the standardization curve informations which was used to happen the concentration of glucose. This tabular array shows the optical density of standard glucose solutions and diluted glucose solutions which were measured at 500nm. These measurings were taken utilizing a spectrophotometer. Figure 1 shows a standardization curve used to happen an unknown concentration of glucose in 2. 45g of orange with optical density on the y-axis and concentration on the x-axis which are in extras.


Harmonizing to Beer-lambert’s jurisprudence. optical density is straight relative to the concentration of a solution and the strength of the visible radiation is relative to the concentration of a solution under stable conditions. In this experiment the Torahs environing optical density which is the Beer-lambert jurisprudence was obeyed ( Reed et al. 2007 ) . From figure 1 which is a standardization curve shows that the graph is additive which means the Beer-lambert Torahs were obeyed. In table 1 the optical density values of the solution were taken in extras toavoid any mistakes. The optical density values shown in the tabular array hold merely a little difference from one another which shows that the values were accurate. These values were taken utilizing a spectrophotometry accomplishments and a spectrophotometer. A spectrophotometer is a device that radiances light through a solution mensurating its optical density of the visible radiation at certain wavelengths. In this experiment. the optical density of criterion and diluted glucose solutions were taken at 500nm. These optical density values as shown in table 1 were used to plot a standardization curve to happen an unknown concentration of glucose. From the tabular array there were duplicate values for each solution or sample.

These samples were so plotted on a graph and a line of best tantrum was drawn through those points. To obtain the concentration of glucose based on the graph. the value of one of the terra incognitas was chosen which was within the scope of the graph was chosen and traced to run into the line of best tantrum and the concentration was derived. From the tabular array. optical density increased as the concentration increased demoing preciseness and as for truth. the difference between the first and 2nd tests were minimum. In this experiment and in other experiments like these. mistakes could be caused by improper handling of GOD-PAP check and cuvettes. wrong arrangement of cuvette into the spectrophotometer and hapless standardization of the spectrophotometer. Mistakes could besides be made when plotting a graph for the standardization curve. Weighing the incorrect sum of orange. For such mistakes to be avoided in future experiments. the GOD-PAP check should be handled with attention and dispensed consequently.

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The cuvettes should besides be handled with attention and avoid touching the crystalline side of the cuvette so as non to hold fingerprints and inaccurate readings. Sing the cuvette. they should be placed with the crystalline side confronting the visible radiation doing it easy for the visible radiation to reflect through. Proper graduated table should be used to plot the graphs to give a good graph and standardization curve. Without a good graduated table. there will be trouble in pulling the line of best tantrum. Weighing the right mass of orange is really of import so as to acquire accurate readings. There should ever be a control or a clean solution which should besides be in extras. These controls are used to zero the spectrophotometer for optical density readings to be taken. An orange carries different types of sugars chiefly sucrose. glucose and fruit sugar. In an orange. there are 13g of natural sugars otherwise known as invert sugars. These sugars which are sucrose. glucose and fructose do up that 13g with sucrose being the most abundant sugar in an orange with 6. 5g. Sucrose is a disaccharide made of two monosaccharoses known as glucose and fruit sugar which are besides sugar contents of an orange.

From the computations carried out in this experiment. it was gathered that an orange carries about 3g of glucose go forthing fruit sugar to be 3. 5g in an orange which is the 2nd highest sum ( livestrong. com ) . Without experiments like these. people will ever believe glucose represents the entire sum of sugar in an orange because it is believed that glucose makes everything Sweet. In this experiment. the concentration of glucose was found to be 3g in an mean orange. This was done with utilizing the cognition of spectrophotometry and Beer-lambert’s jurisprudence. Besides. the concentration of glucose was found utilizing an enzymatic method known as the GOD-PAP check and standardization curve. With this experiment. it has been made known that glucose does non stand for the overall sugar content of an orange and in fact is the least most abundant sugar in an orange.

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An orange besides contains other types of sugars like saccharose and fructose with sucrose being the highest sugar constituent. The standardization curve obeyed Beer-lambert’s jurisprudence because of its additive construction. Accuracy and preciseness of consequences were gotten because they were taken in extras. The difference between the optical density values were minimum ( consequences stayed in the same scope ) doing the consequences accurate. An increasing optical density was besides recorded as the concentration increased. Overall. the chief purpose of the experiment was achieved which was finding concentration of glucose in an orange. The usage of assorted equipments were understood and put into pattern.


1. Reed. R. . Holmes. D. . Weyers. J. . Jones. A. ( 2007 ) Practical Skills in Biomolecular Sciences. 3rd edn. . Essex: Pearson.

2. Ochs. C ( 2010 ) Natural Sugars in Oranges. Available at: World Wide Web. livestrong. com/article/267094-natural-sugars-in-oranges/ ( Accessed: 15th November 2013 ) .

3. Coventry University. Schedule 116 BMS. ( 2013 ) Determination Of The Glucose Content O An Orange