Lab – Spectrophotometry for the qualitative and quantitative measurement of biochemical compounds

OBJECTIVES:

At the conclusion of this unit the student will be expected to:

Apply the principles of spectrophotometry to the qualitative and quantitative measurement of biochemical compounds.

LABORATORY SEQUENCE:

1. Pre-lab discussion on the program for the session and familiarization with the spectrophotometer.

2. Prepare a standard curve for inorganic phosphate using the spectrophotometer.

3. Determine the concentration (unknown) of a solution of inorganic phosphate.

4. Determine the absorption spectrum of p-nitrophenol

5. Determine the molar extinction coefficient for p-nitrophenol and learn what it means and how it can be used.

6. Post-lab discussion on the results from the laboratory session and what follow up is needed.

Question:

Calculate the molar extinction coefficient (e) at the wavelength for the maximum absorption in alkaline solution and explain the meaning of the calculated value.

Format: the reports should be double spaced, using size 12 fonts, and font type Arial or Times New Roman.

Reports must be organised according to the following guidelines, containing:
TITLE: Clear and full title that indicates the content of the report.

ABSTRACT: A short paragraph describing the aims, results and outcomes of the experiment or investigation. One to two sentences for each of these sections should be sufficient. Do not use references within the abstract section. The complete abstract should be no more than 200 words.

INTRODUCTION: A brief, but adequately referenced background to the report in which the significance of the project is clearly defined. This section is not a complete review and should contain background necessary to conduct the experiment, as well as aims and objectives. This whole section should not exceed 1000 words.

METHODS: Summarise the essential experimental procedures (do not simply reproduce the instructions in the manual) and reference adequately, including the laboratory manual. In particular, note any changes to published procedures. The purpose of this section is to provide enough information and detail to allow a competent worker in the field to reproduce the experiments.

RESULTS: Text – Each data set presented in Results should be preceded by text describing how the data was collected, and specific reference to the appropriate data set (eg, Figure 12, Table 12, etc). The text following each data set should then summarise quantitative data and observations presented in the data set (eg, table, graph, diagram, etc, as appropriate). The author’s interpretation of the data should always be described in words in the text, but do not discuss the results at this stage (see below). A series of tables or graphs presented by themselves is insufficient.

Any conclusions that can be drawn from the graphs, tables and observations illustrated in the diagrams should be stated briefly. In some cases this will involve statistical analyses of the data which evaluates whether treatment effects are real or due to biological variation.

Figures and Tables – In presenting results, give all figures (including graphs and diagrams) and tables, a title and a number. Use the number, e.g. Figure 12, Table 12, etc. when referring to the data in the text. Figures should be accompanied by a figure legend (which includes the title of the figure) placed beneath the figure and clearly distinguishable from the main text of the Results section. Tables should have a title placed above the table. Tables should not be broken across pages.

Both the Figure legend and the Table heading should include sufficient detail to understand the data presented in them without referring to the text. The axes on graphs should be labelled so that they can be interpreted without reference to the text.
Include on the Table or Figure, the units in which the weights, areas, volumes, rates, etc, are expressed.

For hand drawn images a reproduction of your lab book is adequate. Therefore, it is very important to record results carefully and accurately during the laboratory sessions.

Draw graphs wherever possible, as these enable you to get an overall picture of the data obtained. Remember that graphs have a visual impact and draw them accordingly. Choose the dimensions of each axis carefully. In general the two axes should be of about equal length. Mark every point that you are plotting clearly. If you include more than one set of figures on a single graph, use a different symbol for each (open circles, closed circles, triangles, etc.), and key these symbols in the figure legend or embeIDed in the graph itself.
An appendix may be used where appropriate to present raw data (including class and your own clearly identified data), calculations (including all clearly described steps), etc.

Remember to refer to ALL your figures/tables/appendices in the text of your Results.

This section should be no more than 500 words, excluding figure and table legends.

DISCUSSION: Discuss the results and what they mean. Highlight important findings and any inadequacies of the data. You will need to use and refer to literature to support your arguments. Are your findings supported by the literature? Discuss. Make sure you have aIDressed all the aims as presented in the introduction.

Complete the discussion with a final sentence or two presenting your overall conclusions on your experiment with reference to the original aims. This final concluding paragraph should contain no references.

This section should be no more than 800-1000 words.

REFERENCES: References in text: Each reference cited in your text must be listed in the References list and vice versa: please check these carefully.

Use the format used by the Journal of Food Science. The journal is available in electronic form in the library collection. Some basic information for this referencing style is presented below, for more information consult a recent edition of the Journal of Food Science:
In text. Cite publications in text with author name and year. Use “and others” rather than “et al.” In parenthetical citations, do not separate author and year with a comma. Use commas to separate publications in different years by the same author. Semicolons separate citations of different authors. Cite two or more publications of different authors in chronological sequence, from earliest to latest. For example:
– The starch granules are normally elongated in the milk stage (Brown 1956).
– Smith and others (1994) reported growth . . . . . .
– … and work (Dawson and Briggs 1984, 1987) has shown that …
– … and work (Dawson 1984; Briggs 1999) has shown that ….
In References section. List only those references cited in the text. References should be listed alphabetically by the first author’s last name. Single author precedes same author with co-authors. Type references flush left as separate paragraphs (do not indent manually, let the text wrap). Use the following format (note order, use of periods, and spacing):
– Journal articles: Author(s). Year. Article title. Journal title volume number (issue number): inclusive pages.
Example:
Citation in text: (Smith and others 1999)
Reference list: Smith JB, Jones LB, Rackly KR. 1999. Maillard browning in apples. J Food Sci 64(4):512-8.
– Books: Author(s) or [editor(s)]. Year. Title. Place of publication: publisher name. Number of pages.
Example:
Citation in text: (Spally and Morgan 1989)
Reference list: Spally MR, Morgan SS.1989. Methods of food analysis. 2nd ed. New York: Elsevier. p. 682.
– Chapter: Author(s) of the chapter. Year. Title of the chapter. In: author(s) or editor(s). Title of the book. Edition or volume if relevant. Place of publication: publisher. Pages of the chapter.
Example:
Citation in text: (Rich and Ellis 1998)
Reference list: Rich RQ, Ellis MT. 1998. Lipid oxidation in fish muscle. In: Moody JJ, Lasky, UV, editors. Lipid oxidation in food. 6th ed. New York: Pergamon. p 832-55.

The use of Internet references is NOT PERMITTED unless citing educational or non-for profit organisations (Universities, WHO, FAO, CSIRO etc). The total internet references should not exceed 10% of the total number of references.

Under NO circumstances can Wikipedia or similar sources be used as a reference. These articles are not peer reviewed, and so are not permissible for use in a scientific document.

Attachment:- Lab report.rar