Chem. 231 – 4/8 Lecture
Announcements
• Set 1 Lab Reports
– hand back
• Set 2 Lab Reports
– Due 4/10
• Final Exam – April 15th
• Future Mondays (after 4/15)
– Set 3 Presentation – 4/29
– 4/22 and other Mondays
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can’t start lab at 5:00 in Sequoia 538 (Chem 125 conflict)
can run lab from 5:30 to 9:00 or
5:30 to 8:30 plus Wed from 5:00 to 8:00 or
first 30 min of lab in Sequoia 540
Labs – More Details
• Set 2 Lab Reports
– Real sample analysis will count for at most 25% of
points (less for HPLC lab)
• Set 3 Labs
– We have tristearin and tripalmitin that can be used as
recovery standards
– We also have old linoleic (C18:2) and linolenic
(C18:3) acid standards that can be used as qualitative
standards (these standards decompose easily)
– These are in 540 freezer
– You should be deciding on your “real” sample soon
and let me know what other equipment or standards
you will need
Labs – More Details
• Set 3 Labs – cont.
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Tentative presentation and paper due dates
Presentation 4/29 (1 week after finishing lab)
Paper due 5/6
Presentation should be focused on your sample of
interest and should include some literature research
(why is this sample of interest and what analysis has
been done previously)
Labs – More Details
• Term Project
– You should figure out what you plan to do before
next Monday
– Two options:
• isolation of significant ingredient from household product
(best for 5 to 50% that ingredient)
• use of “new” equipment for analysis of compound from
sample (e.g. use of HPLC-fluorescence detection for
capsaicin in chile samples or analysis of caffeine in a
beverage by SPME-GC-NPD)
– I will have a sign up
• limit to number of students using particular equipment for
bulk of work (not a problem for isolation projects)
• only 1 student per household sample/ingredient
• you may want to have a back-up compound/plan
Final Exam - Review
• Example posted on-line
• 15% of total grade
• Can use lab notebook and notes from lab lecture
(including slide)
• What to know – from 1/28 lecture
– Understand goals of method optimization and
measures of how well that is accomplished
– Basic safety rules
– How to transfer data (raw, chromatograms, and
software table data) to Excel
– Steps to turning on and off HPLCs and GCs
Final Exam - Review
• What to know – from 2/4 lecture
– Understand goals of simple extractions
– Know some equipment for the following types of
extractions:
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solids into liquids
gases into liquids
gases into solids
removal of solids from fluids
liquid – liquid extraction
solvent reduction
– How Soxhlet extraction works
– How gas trapping works
– Procedure to use SPME (for gases or liquid samples)
Final Exam - Review
• What to know – from 2/4 lecture – cont.
– Requirements and selection of phases for liquid –
liquid extractions
– Purpose of acid/base modifiers in liquid – liquid
extractions
• What to know – from 2/11 lecture
– Basic calculations for liquid – liquid extractions (Q, Kp
and KD)
– How to test for extraction efficiency and ways to
improve extraction efficiency
– Main purpose and equipment with low pressure liquid
chromatography and TLC
Final Exam - Review
• What to know – from 2/11 lecture – cont.
– How to identify problems in integrating peaks
– Some ways to improve peak integration (be able to
describe or give name of control in software)
• What to know – from 2/18 lecture
– How to calculate a limit of detection from a low conc.
standard run
– Calibration Methods
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main types and rationales for use
how to perform linear least squares analysis
some sources of uncertainty
how to use internal standard and surrogate standard
methods
Final Exam - Review
• What to know – from 2/25 lecture
– Advantages to GC methods
– Limitation of GC methods to certain analytes/samples
– Requirements to use GC for permanent gases and
non-volatile compounds
• What to know – from 3/4 lecture
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SPE use procedure
Basic structure of phenols and monterpenes
Factors to consider when selecting HPLC solvents
Advantages/disadvantages to low and high pressure
mixing
Final Exam - Review
• What to know – from 3/11 lecture
– SPE use procedure
– How HPLC pumps and injectors work
– How to avoid peak broadening associated with
injection
– Know how column dimensions (both GC and HPLC)
affect separation performance
– Know the difference in needs between selective and
universal detectors