Wait a second!
More handpicked essays just for you.
More handpicked essays just for you.
Colorimetric determination
Don’t take our word for it - see why 10 million students trust us with their essay needs.
The phenol-sulfuric acid method is a simple and rapid colorimetric method to determine total sugar in a sample. The method detects virtually all classes of carbohydrates, including mono-, di-, oligo-, and polysaccharides. It is one of the most versatile, relatively easy and cheap approaches for determination of carbohydrate concentrations is the colorimetric method based on reaction between hydrolysed carbohydrate solution and a colouring reagent that develops colour that is detectible in the visible range of the electromagnetic spectrum. Reagents used for colorimetric detection include phenol and concentrated sulphuric acid. The furfural is allowed to develop colour by reaction with phenol and its concentration is detected by visible light absorption. …show more content…
Pentoses (5-carbon compounds) are then dehydrated to furfural, and hexoses (6-carbon compounds) to hydroxymethyl furfural. The phenol-sulphuric method is used for the estimation of total sugars and DNS method for reducing sugars. Reducing sugars have an aldehyde group or carbonyl functional group, which can be reduced to -OH group by chemical reaction by addition of the DNS reagent. Some sugars like fructose/ sucrose which is commonly found in fruit juice are non-reducing sugars and hence do not reduce the above because of absence of an aldehyde group which is why the phenol sulphuric method is
Data from Table 1. confirms the theory that as the concentration of glucose increases so will the absorbance of the solution when examined with the glucose oxidase/horseradish peroxidase assay. Glucose within the context of this assay is determined by the amount of ferricyanide, determined by absornace, which is produced in a one to one ratio.1 Furthermore when examining the glucose standards, a linear calibration curve was able to be produced (shown as Figure 1). Noted the R2 value of the y = 1.808x - 0.0125 trend line is 0.9958, which is statistically considered linear. From this calibration curve the absorbance values of unknowns samples can be compared, and the correlated glucose concentration can then be approximated.
These labels indicated the lactose solution that was be placed into the mini-microfuge tubes. The varying lactose ph solutions were obtained. The four miniature pipets were then used, (one per solution,) to add 1mL of the solution to the corresponding mini-microfuge tubes. When this step is completed there were two mini-microfuge tubes that matched the paper towel. Then, once all of the solutions contained their respective lactose solutions, 0.5mL of the lactase enzyme suspension was added to the first mini-microfuge tube labeled LPH4 on the paper towel, and 4 on the microfuge tube. As soon as the lactase enzyme suspension was added to the mini-microfuge tube, the timer was started in stopwatch mode (increasing.) When the timer reached 7 minutes and 30 seconds, the glucose test strip was dipped into the created solution in the mini-microfuge tube for 2 seconds (keep timer going, as the timer is also needed for the glucose strip. Once the two seconds had elapsed, the test strip was immediately removed, and the excess solution was wiped gently on the side of the mini-microfuge tube. The timer was continued for 30 addition seconds. Once the timer reached 7:32 (the extra two seconds accounting for the glucose dip), the test strip was then compared the glucose test strip color chart that is found on the side of the glucose test strip
To uncover organic compounds like carbohydrates, lipids, proteins and nucleic acid, by using tests like Benedict, Lugol, Biuret and Beta Carotene. Each test was used to determine the presents of different organic molecules in substances. The substances that were tested for in each unknown sample were sugars, starches, fats, and oils. Moreover, carbohydrates are divided into two categories, simple and complex sugars. Additionally, for nonreducing sugars, according to Stanley R. Benedict, the bond is broken only by high heat to make make the molecules have a free aldehydes (Benedict). As for Lipids, there are two categories saturated and unsaturated fats. One of the difference is that saturated fats are mostly solids and have no double bond (Campbell Biology 73). The Beta Carotene test works by dissolving in a lipid, thus giving it color to make it visible. Moreover, proteins are made out of amino acids that are linked by a polypeptide bond (Campbell Biology 75). The purpose of this experiment was to determine whether an unknown class sample or food sample had any carbohydrates, lipids, or proteins in it. The expected result of the lab was that some substances would be present while other would be absent.
The unknown substance is probably a carbohydrate because it tested positive for starch which is a polysaccharide. This reaction also had very similar results as the Lugol’s test for potatoes which is a polysaccharide. Although the colors from the test for potatoes were not the same colors as the test for the unknown; the Biuret test had a slight color change and the Lugol’s test had a dramatic color change for both the unknown and potatoes. I am sure that the unknown was a starch, but the Benedict’s test for sugar was positive for the potatoes while the Benedict’s test for the unknown didn’t have a color change. The unknown probably did not have a color change for the Benedict’s test simply because there were not enough sugar present in the unknown for it to test positive. The Sudan IV Test for Lipids did not test positive for the unknown nor the potatoes because there isn’t a trace of lipids in starch. Based on my results, the unknown has a little protein, a lot of starch and no traces of lipids or
The solute is the same: sucrose;C12H22O6(sugar) 2.
The independent variable for this experiment is the enzyme concentration, and the range chosen is from 1% to 5% with the measurements of 1, 2, 4, and 5%. The dependant variable to be measured is the absorbance of the absorbance of the solution within a colorimeter, Equipments: Iodine solution: used to test for present of starch - Amylase solution - 1% starch solution - 1 pipette - 3 syringes - 8 test tubes – Stop clock - Water bath at 37oc - Distilled water- colorimeter Method: = == ==
Table sugar, or sucrose, is a disaccharide that is a combination of one glucose molecule and one fructose molecule. On the other hand, Sweet’N Low, also known as saccharin, is a sugar that triggers the taste buds of human tongues, but goes through the digestive system relatively untouched. Just like humans, yeast can not fully digest saccharin, so the amount of energy gained from the saccharin in decreased compared to the amount gained from sucrose. Since yeast can’t break down saccharin very well, it can’t do cellular respiration to produce the carbon dioxide that is measured for the experiment. In contrast, sucrose is made of two molecules that the yeast can break down easily. Yeast doesn’t react to how sweet the sweetener is, but the amount of energy stored within it.
The progress of this reaction was monitored using Dinitrosyl alcohol. (DNS) as the reagent reacts with the reduced sugar products. The The colour of DNS changes from yellow to varying shades of red depending on the color of the DNS. on the on the reducing sugars product being found with time. The light absorption from the varying colours of solutions can then be measured calorimetrically.
Protocol First, we measured out 1, 3, and 5 grams of sucrose into a weigh boat and added each sample to 100 mL of distilled water. This gave us a 1%, 3%, and 5% sucrose solution. Then we activated the yeast by stirring 1 packet (7 grams) of yeast into 250mL of warm water. Then we place 11 mL of each sucrose solution into separate fermentation vials and filled the rest with the yeast solution.
All monosaccharides are reducing sugars because they all aldehydes. Different monosaccharides contain different number of carbon atoms. There are three types of monosaccharides, trioses, pentose and hexose. They generally contain three (trioses), five (pentoses) or six (hexoses) carbon atoms. Triose is used as a product in biochemical pathways of respiration and photosynthesis.
Carbohydrates supply 80-90% of dietary energy. Sugars, starch, cellulose and related substances are carbohydrates. Starch is more easily digested than cellulose. Grains are easy to digest as they are 60-80% starch. (arg.gov.sk.ca) A recent study conducted by Sharon R. Bullimore et. all. investigated the result of supplementing the diet of endurance horses with fructose rather than glucose. They “conclude that fructose is well-absorbed by horses and rapidly converted to glucose.”
By taking a Carbon Dioxide, rich substance and mixing it with a yeast, solution fermentation will occur, and then it could be determined if it is a good energy-producer. In this study glacatose, sucrose, glycine, glucose, and water were used to indicate how fast fermentation occurred. The overall result shows that monosaccharides in particular galactose and glucose were the best energy source for a cell.
Photosynthesis is, “the process by which plants convert light energy from the Sun into chemical energy in the form of carbohydrates” thus producing, “food for all living organisms, directly or indirectly” (Zheng). Photosynthesis has been examined in thousands of different ways. Many of these experiments include studying the rate of photosynthesis and pigment accumulation by obtaining plants and then stressing their light and nutrient intake (Okunlola and Adekunle). Photosynthetic pigments reflect and absorb different wavelengths of visible light based off their polarity. In this experiment, we studied photosynthetic pigments, first, by determining polarity and then, by measuring the amount of light of a given wavelength that a pigment absorbs. We used two methods in this experiment, chromatography and spectrophotometry. Chromatography “is a method used to separate mixtures of substances into their components” (lab book) and spectrophotometry is the use of a spectrophotometer to measure transmittance of light through a liquid. We used our knowledge of polarity to predict that since the least polar pigments move the most, pigment 1 is chlorophyll b, pigment 2 is chlorophyll a, pigment 3 is an anthocyanin, pigment 4 is a xanthophyll, and since most polar pigments move the least, pigment 5 is
The Benedict's Test is used to test the presence of simple sugars in a sample. If sugars are present, a color change will occur from blue to red. However, although the Benedict's test shows the presence of sugars, it cannot accurately determine the concentration of sugar in a sample solution. In our method, we added specific concentrations of glucose to the Benedict's test to use as a chart to estimate the glucose concentration of an unknown solution X. Although this gives a rough estimate of the concentration, it is very inaccurate. For example, the mystery solution X was a pale orange color, which was between the colors in my first and second test tube.
To determine the difference between sucrose and the corn syrup you can perform the Barfoed’s test because sucrose will fail the test because it is a non-reducing disaccharide while corn syrup will pass because corn syrup is a combination of glucose and