Biochemistry LABORATORY NOTEBOOK AND EXPERIMENT REPORTS

The laboratory notebook: This means that procedural details, observations, and results must be recorded in a laboratory notebook while the experiment is being performed.

Outline of experimental write-up I. Introduction (a)Objective or purpose (b)Theory II. Experimental (a)Table of materials and reagents (b)List of equipment (c)Flowchart (d)Record of procedure

Outline of experimental write-up III. Data and Calculations (a)Record of all raw data including printouts (b)Method of calculation with statistical analysis (c)Present final data in tables, graphs, or figures when appropriate.

Outline of experimental write-up IV. Results and Discussion (a)Conclusion (b)Compare results with known values (c)Discuss the significance of the data (d)Was the original objective achieved? (e)Literature references.

Details of Experimental Write-Up I. Introduction For preparing this statement, ask yourself, “ What are the goals of this experiment?” This statement is followed by a brief discussion of the theory behind the experiment. If a new technique or instrumental method is introduced, give a brief description of the method. Include chemical or biochemical reactions when appropriate.

Details of Experimental Write-Up II. Experimental 1. Begin this section with a list of all reagents and materials used in the experiment. The sources of all chemicals and the concentrations of solutions should be listed. Instrumentation is listed with reference to company name and model number. A flowchart to describe the stepwise procedure for the experiment should be included after the list of equipment. The write-up to this point is to be completed as a Prelab assignment.

Details of Experimental Write-Up II. Experimental 2.The experimental procedure followed is then recorded in your notebook as you proceed through the experiment. The detail should be sufficient so that a fellow student can use your notebook as a guide. You should include observations, such as color changes or gas evolution, made during the experiment.

Details of Experimental Write-Up II. Experimental 3.If you obtain a recorder printout of numbers, a spectrum from a spectrophotometer, or a photograph, these records must be saved and handed in with your report.

Details of Experimental Write-Up III. Data and Calculations All raw data from the experiment are to be recorded directly in your notebook, not on separate sheets of paper or paper towels. Calculations involving the data must be included for at least one series of measurements. Proper statistical analysis must be included in this section. For many experiments, the clearest presentation of data is in a tabular or graphical form.

Details of Experimental Write-Up IV. Results and Discussion 1.This is the most important section of your write-up, because it answers the questions, “Did you achieve your proposed goals and objectives?” and “What is the significance of the data?” Any conclusion that you make must be supported by experimental results.

Details of Experimental Write-Up IV. Results and Discussion 2.It is often possible to compare your data with known values and results from the literature. If this is feasible, calculate percentage error and explain any differences. If problems were encountered in the experiment, these should be outlined with possible remedies for future experiments.

Details of Experimental Write-Up IV. Results and Discussion 3.All library references (books, journal articles, and Web sites) that were used to write up the experiment should be listed at the end. 4.Everyone has his or her own writing style, some better than others. It is imperative that you continually try to improve your writing skills.

C. STORAGE OF SOLUTIONS 1.The storage conditions of reagents and solutions are especially critical. Although some will remain stable indefinitely at room temperature, it is good practice to store all solutions in a closed container. Often it is necessary to store some solutions in a refrigerator at 4 0C. Some solutions may require storage below 0 0C.

C. STORAGE OF SOLUTIONS 2.Stored solutions must always have a label containing the name and concentration of the solution, the date prepared, and the name of the preparer.

C. STORAGE OF SOLUTIONS 3.All stored containers, whether at room temperature, 4 0C, or below freezing, must be properly sealed. This reduces contamination by bacteria and vapors in the laboratory air (CO2, NH3, HCl, etc.)

D. QUANTITATIVE TRANSFER OF LIQUIDS Automatic pipetting Systems For most quantitative transfers, including many identical small-volume transfers, a mechanical microliter pipettor is ideal. This allows accurate and rapid dispensing of fixed volumes from 1 to 5000 ml. The pipet’s push- button system can be operated with one hand, and it is fitted with detachable polypropylene tips.

How to use an adjustable pipetting device 1.Set the digital micrometer to the desired volume using the adjustment knob. Attach a new disposable tip to the shaft of the pipet. Press on firmly with a slight twisting motion.

How to use an adjustable pipetting device 2.Depress the plunger to the first positive stop, immerse the disposable tip into the sample liquid to a depth of 2 to 4 mm, and allow the pushbutton to return slowly to the up position and wait 1 to 2 seconds.

How to use an adjustable pipetting device 3.To dispense sample, place the tip end against the side wall of the receiving vessel and depress the plunger slowly to the first stop. Wait 2 to 3 seconds, and then depress the plunger to the second stop to achieve final blow-out.

How to use an adjustable pipetting device 4.Withdraw the device from the vessel carefully with the tip sliding along the inside wall of the vessel. Allow the plunger to return to the up position. Discard the tip by depressing the tip ejector button.

On the Web http://www.graphpad.com/prism/Prism.htm Software for statistics and curve fitting. http://www.gilson.com/pipe.htm Information on automatic pipets, procedures for use, and helpful hints. http://www.hendrix.edu/chemistry/chemsafe.htm Information on chemical hygiene and safety with links to MSDS searches. http://www.dixie.edu/mort/manual/mechanics/Notebook.html How and why to keep a notebook. Procedures for use and helpful hints.