Instructor Chem 14H Fall 2000

Dr. Jackie Bortiatynski, Director of Instrumentation:

Office: 211A Whitmore Laboratory

Office Hours: Tuesdays and Thursdays, 9:00 am ­ 10 am or by appointment

Email address: jackie@chem.psu.edu
 
 

Teaching Assistants Chem 14H Fall 2000

Christie Vu

Office: 206 Chandlee Laboratory

Office Hours:

Email Address: bcv3@psu.edu

Chris Loope

Office: 331 Whitmore Laboratory

Office Hours:

Email Address: cloope@chem.psu.edu

Dick Gueldner

Office 211 Whitmore Laboratory

Office Hours:

Email Address: rcg7@psu.edu

Staff Assistant Chem 14H

Diane Colella

Office: 210 Whitmore Laboratory

Office Hours: 8:00 am till 5:00 PM Monday through Friday

Phone: 863-3261

Email Address: dvc6@psu.edu

Diane handles drop/add and other administrative details for this course.
 
 
 
 

Library Resources

The Penn State Library web site has a very helpful online tutorial that all students in Chem 14H are required to visit as a homework assignment. This tutorial was designed to aid in the library search of a research topic. The tutorial entitled "Information Literacy and You" is divided into nine sections. Many of the sections have an embedded "Research Log" for you to make notes on the topic you have just completed. You are required to fill out all of these research logs and print them out for your TA. This homework exercise will provide you with the tools you will need to do data base searches to find literature references for your research project. There has been no date set in the formal schedule to turn in your Research Log materials from the tutorials. Your laboratory TA will assign a date to turn in your Research Logs after you have chosen your research project. You have been provided with information on how to access The Journal of Chemical Education in your Chem 14H/12H packet to on page 192. The following instructions will guide you to the tutorial on the Penn State Library web site.

The URL for the portion of the web site dealing with instruction is found at www.libraries.psu.edu/crsweb/infolit/andyou/infoyou.htm. Once you are on this page click on For Students, which will give you a brief description of the tutorial. Then work your way through the various modules making sure that you complete all of the Research Logs.
 
 

Instrument Room Resources

You will carry out all of your analyses in either the Instrument Room (206 Whitmore) or the Analytical Laboratory (330 Whitmore Laboratory). The instruments available to 14H students in the Instrument Room are: two gas chromatographs, a gas chromatograph/mass spectrometer, an ultraviolet/visible spectrophotometer, and a high performance liquid chromatograph. You will have a brief introduction to each of these instruments during as well as the atomic absorption spectrophotometer and the ion chromatograph located in the Analytical Laboratory during your regularly scheduled lab periods. You will be required to return to the instrument room outside of laboratory classroom time to view tutorials and run standards on the ultraviolet/visible spectrophotometer, and a gas chromatograph. The Instrument Room is open from 9:00 am till 9:30 pm Monday through Thursday and on Friday from 9:00 am till 5:00 pm. The Instrument Room is staffed by Chemistry Laboratory TA’s who are currently teaching Chem 36 and Chem 431. These TAs are familiar with all the equipment but they are there to assist you not to run your experiments. You will receive additional instruction from the Chem 14H TAs. In addition we have one Instrument Room TA, Nick Hartman, who has been hired to assist Chem 14H students during the project portion of the semester. The most convenient hours for Chem 14H students to operate equipment will be on Mondays, Wednesdays, and Fridays when the organic laboratories are not in session. There are sign up books for all the instruments in the Instrument Room and you are required to sign up for no more than a one hour block of time per session. If you require more time per session please see Dr. Bortiatynski for scheduling.

Instrument Room TA for 14H

Nick Hartman

Email Address: nickhartman@psu.edu

Instrument Room Hours:x

Any changes in the due dates of laboratory assignments will be announced in Chem 12H lecture and or in the Chem 14H laboratory sessions. These changes will only occur if unexpected circumstances arise during the semester so plan your time accordingly.
 
 
 
 
 
 
 
 

Grading
 
 

THE FINAL GRADE:

Poster: 150 points

Project: 300 points

Evaluation: 100 points
 
 

POINT DISTRIBUTION:

Exp #3 A-D ÷ , ÷ + , ÷ -

Exp #3 E-H 100 points

Exp #2 200 points

Exp #4 200 points

Exp #7, Solutions and Reactions I 200 points

Exp #7, Solutions and Reactions II 200 points

Exp #8, 100 points
 
 

Library Tutorial: Information Literacy and You

www.libraries.psu.edu/crsweb/infolit/andyou/infoyou.htm
 
 
 
 
 
 
 
 

Berkley MultiCHEM site for interactive demos

http://mc2.CChem.Berkeley.EDU/MultiCHEM/

http://courses.chem.psu.edu/chem36/UVVIS/Index.htm
 
 
 
 

Physical Sciences Library Web Site

http://www.libraries.psu.edu/crsweb/physci/
 
 

You will be required to utilize at least one of the following instruments to complete your project: gas chromatograph, gas chromatograph/mass spectrometer, ultraviolet/visible spectrophotometer, high performance liquid chromatography, atomic absorption spectrophotometer, and an ion chromatograph. An introduction to each of these instruments will assist you during your training and in designing the experimental section of your project.

*Click here for a Materials List that you will need to fill out and return to the stockroom in 104 Whitmore Lab prior to beginning your project. If chemicals will need to be ordered fill out your sheet as soon as possible.
 
 

Ultraviolet/Visible Spectrophotometry

THEORY: Ultraviolet and visible spectra are dependent on the electronic structure of the substance in question. The absorption process generally results from the excitation of electrons in chemical bonds by a photon of energy. As a consequence, the wavelengths of absorption can be correlated with types of bonds thus providing a valuable tool for identifying functional groups in a molecule. Even more importantly in our case, this form of absorption spectroscopy is a valuable tool for the quantitative determination of molecules containing bonds that absorb energy in the UV or visible range of the electromagnetic spectrum. All organic molecules absorb energy in the ultraviolet region of the spectrum, however some of the associated absorptions are located in the vacuum UV which is a difficult region of the spectrum to examine without very specialized equipment. For this reason we will concentrate on those molecules that absorb in the electromagnetic spectrum between 200 to 800 nm (UV spectrum from 200 to 380 nm and the visible spectrum from 400 to 800 nm). Because we are interested in molecules that absorb in this region of the electromagnetic spectrum we are limited to a number of functional groups called chromophores which have valence electrons with relatively low excitation energies. Generally bonding electrons with low excitation energies are found in double bonds between atoms. Electronic spectra of chromophores are usually complex and do not result in single sharp lines as you might expect. Instead the absorption peak looks like a broad hump. This is due to the fact that lower energy transitions such vibrational and rotational absorptions are superimposed on the electronic absorptions which results in band of wavelengths rather than a single line. The broad absorptions make it difficult to identify an unknown compound solely on its UV/VIS spectrum. UV/VIS spectra are most commonly used as a way to quantify the amount of a known compound by monitoring changes in the intensity of the most intense absorption peaks. The most intense peak in the spectrum is called the l_{max and often times this is the peak that is monitored in quantitative studies. The intensity of the absorptions in the UV/VIS spectra are dependent upon the concentration of the chromophores in the solution. The concentration of a known compound (solute) in a solution can be calculated using Beer’s Law where: A=} e bc

A = absorbance in absorbance units

e = the molar absorptivity, a constant characteristic of the solute

b = the path length through the cell (10 mm)

A standard curve is created from the plot of absorbance versus concentration over the predicted concentration range of analyses that are to follow using unknown amounts of a known solute. The concentration of any solution containing the known compound can be extrapolated from the graph as long as the absorbance remains within the limits of the standard curve.
 
 

SOLVENT: In choosing a solvent for UV/VIS analysis you must always be aware of the fact that it too will have an UV spectrum. You do not want the UV maxima of your solvent to interfere with the absorbances of your sample. A list of common UV/VIS solvents and their associated UV maxima are found in the UV/VIS compendia next to the instrument. It is also important to note that the polarity of the solvent will also affect the sharpness the peaks in the absorption spectra so if you are looking for a fine separation of peaks you will need to choose a less polar solvent.
 
 

CUVETTE: Choosing the proper cuvette or sample holder is also important before running an experiment. The cuvettes that we use in this spectrometer are rectangular shaped vials with two clear sides and two frosted sides. The clear sides always are place in the path of the light, and you always touch the cells on the frosted sides. If you are only concerned with UV absorptions quartz cells should be used because they will be transparent in the region between 200 to 380 nm. For applications in the visible region of the spectrum quartz or plastic cuvettes can be used. The advantage of plastic over quartz is cost. But if you use plastic do not use acetone to rinse the cuvette otherwise you will cloud the cell and it can not be used for further measurements.

SAMPLE PREP: A solution for UV/VIS analysis is prepared by dissolving about one milligram of your sample in 10 mL of distilled water or 95% ethanol. This is only a starting point you may have to dilute your solution if any of the maxima are greater than one absorbance unit. The cuvette should be cleaned thoroughly after each use. Rinse the cuvette with your dilution solvent and then rinse with 95% ethanol or methanol.
 
 

BLANK: For more accurate measurements a blank must be run before acquiring any data. The blank or reference and the solution containing your sample must be closely matched. The most obvious choice for the blank is the solvent or solvent system that was used to dissolve the sample. The data obtained in the blank run is subtracted from all subsequent runs, thus it serves as a means of removing as much back ground interference from the spectrum as possible.
 
 

Biological Chemistry
 
 

1. A study on the properties of natural dyes. Does the pH of your wash water effect the brightness of clothes dyed the old fashion way?
 
 

2. Develop a colorimetric analysis to study the fermentation of sugars to alcohols.
 
 

3. Extraction of DNA from plant and animal materials; characterization comparison to DNA purchased from suppliers
 
 

4. Our stomach is truly a melting pot. Is the digestion of some sugars inhibited by some of the things we drink? Is lactose digestion inhibited by tannins found in teas?
 
 

5. Examine the natural transesterification of esters. Why does a blended mixture of fresh peas, brown sugar and apple smell like strawberries?
 
 

6. What is combinatorial chemistry? How does structure influence physical properties of molecules? Development of a laboratory experiment to illustrate the use of combinatorial chemistry via the synthesis of a series of esters.
 
 

7. Development of a does response curve for the exposure of brine shrimp to phenolic pollutants in alcohol water solutions
 
 

8. Choose a protease substrate to investigate ability of fruits to tenderize meat using a colorimetric assay.
 
 
 
 

Analytical Chemistry
 
 

1. The use of photographic paper to study the effectiveness of sun block or sun glasses.
 
 

2. A comparison of the effectiveness of extracting fragrance and flavor compounds using steam distillation versus purge and trap techniques.
 
 

3. Determine the presence of aldehydes in oils used in microwave popcorn or other fast food.
 
 

4. Examination of pesticides in drinking water from local fresh water wells.
 
 

5. Development of a UV method to study the temperature induced unfolding of proteins
 
 

6. The study of thermal yellowing of polyvinyl chloride using colorometric techniques
 
 

7. Development of a laboratory experiment to investigate soil phosphates in fertilized soils.
 
 

8. The construction of a pin hole camera system including the film.(This is a challenge project to be supervised by Andrew Greenberg)
 
 
 
 
 
 

Environmental Chemistry
 
 

1. Development of a small scale wastewater-treatment plant
 
 

2. The effectiveness of zeolites in the detergent industry. How effectve are zeolite at softening water? How effective are zeolites in the removal surfactants in cleaning up water contaminated with surfactants?
 
 

3. Identification of aldehydes produced in the break down of sunscreens
 
 

4. Identification of the aldehydes produced in the combustion of natural gas in city buses
 
 

5. How clean are your fruit and vegetables? Is water washing enough? Are the new fruit washes any good or just a waste of money?
 
 

6. Dr. Minard (Director of the Organic Laboratories in the Department of Chemistry) is a faculty advisor for the aquariums in the HUB. One or more project ideas focusing on the cycling of nutrients and or other aspects of the chemistry of a salt water environment will be added to this list. If interested please see me.
 
 

7. How far away from a cigarette do we need to be to claim we are in a smoke free environment? Analysis of tobacco smoke in indoor environments by measuring nicotine and aldehydes.