Chem. 231 – 1/28 Lecture

IntroductionGoals of Course

• Discussion of More Practical Aspects of Separation Science

• Provide Specific Lab Training in Use of Chromatography Instruments and Simple Separations (e.g. Extractions)

• Facilitate Semi-Independent Student Learning

• Improve Communication Skills

SyllabusClass/Discussion Meeting Times

• Not exactly as in syllabus• We typically have extended discussions and

instrument demonstrations in the beginning• We will end discussion “lectures” about half

the way through the semester; Discussions will then occur for 3rd lab oral presentations

• Some work can be performed outside of class hours (once first lab is completed) provided work doesn’t interfere with other classes and follows department policy

SyllabusWebsite + Discussion

• Additional Course Information on Website

• Discussion Topics– In past, I covered “practical” topics I

thought were important– I expect topics to be divided between

general “practical” information and information specific for the experiments to be performed

SyllabusLaboratory Experiments

• Set 1 Labs– Relatively simple experiments to

demonstrate use of HPLC and GC– Will need to do both laboratory

experiments– One will include quantitative work

that will be reported while the other will just be for competency

SyllabusLaboratory Experiments

• Set 2 Labs– Both labs use extraction methods as

would be typical for extraction of compounds from complicated matrices

– HPLC lab will use solid phase extraction to trap phenols from an aqueous matrix

– GC lab will use solid phase microextraction to trap volatile compounds from gas

SyllabusLaboratory Experiments

• Set 3 Labs– The focus of these experiments will

be to derivatize fatty acids and carbonyl compounds for subsequent analysis by GC and HPLC

– Students will provide additional samples of interest

SyllabusLaboratory Experiments

• Term Project Labs– These are meant to be more

independent– Students can isolate an ingredient

from a household product or– Students can work on a separation

using equipment beyond that used in the first 3 experiments (e.g. use HPLC with fluorescence detection)

Syllabus- Notes on Grading

• Homework and Quizzes– 10% of grade– In discussion and on discussion materials

• Final Exam– 15% of grade– No date set yet because previously given after

discussion lectures end and after set 2 labs begin

– Good dates would be the Monday before or after Spring Break

Syllabus- Notes on Grading (2)

• Lab Reports– 75% of grade– Will submit 4 formal written reports (one

for each lab + for the term project) (65% of grade)

– Will submit one ungraded report for the other set 1 lab (e.g. formal for HPLC and informal for GC)

– Will give one oral report on your particular sample in the (Set 3) derivatization lab (10% of grade)

Lab Safety

• Safety Equipment Required– Goggles, gloves and lab coats needed– Must wear long pants and shoes covering feet

below ankle– Goggles and lab coats should be worn while running

instruments, but gloves only needed when handling chemicals

– Gloves should not be worn outside of labs (people get concerned that you are spreading toxic compounds)

– Gloves can both protect your hands from chemicals (e.g. from dinitrophenylhydrozene) and protect your samples from your hands (e.g. from fatty acids)

Other Lab Equipment Needed

• Lab Notebook (and pen)• Lab Instructions (see e.g. Set 1 Lab

Instructions)• Notes from Discussion• Memory stick/floppy drive

Discussion Topics

• Practical Aspects of Separation Science– example: demonstration and discussion

of how SPE cartridges work and are used

• Specific Tools Needed for Our Labs– example: how to set up file folders to

save data using the Agilent HPLC

Today’s Discussion Topic: Data Processing

• How to Set Up Folders• Saving Raw and Processed Data• Excel Processing of Raw Data• External Standard Calibration Using

Excel

Today in Lab

• Check in to lockers

Data ProcessingHow to Set Up Folders

• Whenever possible, use your own folders• Advantages:

– All your stuff should go there– Nobody else’s stuff should go there– Easier to find data/methods and less likely to have data

overwritten• Disadvantages:

– it takes a little time to set upExample: Chemstation

Data ProcessingSaving Raw Data I

• Raw Chromatographic data consists of time and response(s) (response for a single channel instrument to responses for multichannel instruments)

• Most software programs allow you to obtain raw data

• For some instruments (Buck GC), data presented using Excel looks nicer than software chromatograms (with the exception of no integration)

Data ProcessingSaving Raw Data II

• Steps in Process:– Open file (in ChemStation, you need to be in

Data Analysis mode)

Example: Chemstation

Data ProcessingSaving Raw Data III

• Steps in Process:– Look for way to “export” file or “save file as”

with the output being a “text” file (these usually have a .txt extension)

In ChemStation, text file made as “CSV” file

Data ProcessingSaving Raw Data IV

• Steps in Process:– Once in text format, you can open using

“notepad”, but best to move to Excel– Demonstrate opening Expfil using notepad and

in Excel

Data ProcessingSaving Processed Data I

• For Lab Reports, you will want to incorporate chromatograms

• Besides switching raw data to Excel, you also can use instrument software plots

In ChemStation: use Graphics → Copy to Clipboard

The Alternative (used extensively for these Powerpoint slides) is SHIFT Print Screen:

This Copies the Screen

Demonstrate

Both of these methods allow you to paste chromatograms into other programs

Data ProcessingSaving Processed Data II

• Besides the chromatogram, one often wants other chromatographic data (e.g. retention time, peak area, etc.)

• In ChemStation, this can be copied by using the Control C key

• Then in Excel, the data can be pasted

Click and drag over data box

Data ProcessingData Smoothing in Excel

• Demonstrate using trendline for a running average and also using average function with Excel