CHE 311 (311L) Analytical Chemistry (Lab)sites.usm.edu/electrochem/Analytical Chemistry/Lecture...

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Instructor: Dr. Wujian Miao

Lab Manager: Dr. Jian Sun

The University of Southern MississippiDepartment of Chemistry and Biochemistry

CHE 311 (311L)

Analytical Chemistry (Lab)

About this course

CHE 311-Analytical Chemistry Combined Syllabus can be downloaded from:

http://www.usm.edu/electrochem

Teaching 3. Spring, Summer and Fall Semesters Login Area

UserID “CHE311” and Password “Summer2008”

Few Tips For Success in the Class

• actively attending every class and take good notes

• improving your math (good math is absolutely essential)

• completing all homework and study textbook

• Taking CHE 311L VERY Seriously

• asking questions

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Final grade distribution of fall 2013

0

10

20

30

40

50

A B C D F NA

Final No %A 1 3.03

B 7 21.21

C 13 39.39

D 7 21.21

F 4 12.12

NA 1 3.03

33 100

Final grade distribution of fall 2016Final No %

A 3 13

B 6 26

C 6 26

D 6 26

F 2 9

Total 23 1000

5

10

15

20

25

30

A B C D F

Final grade distribution of spring 2017

Final No %A 1 7

B 4 29

C 7 50

D 2 14

F 0 0

Total 14 1000

10

20

30

40

50

60

A B C D F

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Survey and Q&A

Textbook for this course:

Fundamentals ofAnalytical Chemistry

(9th Ed, 2014)

Skoog-West-Holler-Crouch

Chapter 1

Introduction of

Analytical Chemistry

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What is Analytical Chemistry?

An unknown sample solution

The sample could contain:

(1) Ca2+, Na+, or K+ ions

OR(2) A urine sample from a

potentially pregnant woman

Your job:To tell what is the sample or is the woman pregnant?

Analytical Chemistry

What is the sample? How much is X in the sample?

Qualitative Analysis Quantitative Analysis

Ca2+Flame test

(Brick Red)

(EDTA titration)

Emission Spectroscopy (Spectroscope)

EDTA-CaComplex

Identification Quantitation

Hormone(protein)

Pregnancy Test Strip

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Analytical Chemistry

“The study of methods for determining thecomposition of substances.”

“The science of extraction, identification, andquantitation of an unknown sample.”

“What analytical chemists do!”

Two Areas:

Qualitative Analysis (what?) Quantitative Analysis (how much?)

Roles of Analytical Chemistry

• Forensics• Archaeology• Food• Pharmacy• Medicine

General Steps in a Chemical Analysis

From Greek“Food of gods”

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1. Formulating the Question

2. Selecting Analytical Procedures/Methods

1. What accuracy and precision are required?

2. How much sample is available?

3. What is the concentration range of the analyte?

4. What components of the sample will cause interference?

5. What are the physical and chemical properties of the sample matrix?

6. How many samples are to be analyzed?

Defining the problem:

Numerical Criteria for Selecting Analytical Methods

1. Precision

2. Accuracy

3. Bias

4. Sensitivity

5. Detection Limit

6. Concentration Range (Dynamic range)

7. Selectivity

Other Characteristics to Be Considered in Method of Choice

1. Speed (point of care diagnostic testing)

2. Ease and Convenience

3. Cost and availability of instrument

4. Per-sample cost

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3. Sampling

Aliquot—a portion of a larger whole, especially a

sample taken for chemical analysis or

other treatment.

Random Heterogeneous

Material

Segregated Heterogeneous

Material

4. Sample Preparation

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5. Analysis

6. Reporting and Interpretation

7. Drawing Conclusions

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The International System of Units (SI)

SI (International System of Units) Prefixes

Especially useful in this course

mega M 106

kilo k 103

centi c 10-2

milli m 10-3

micro 10-6

nano n 10-9

pico p 10-12

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Solution Terminology

• solute

• solvent

• aqueous solution

• liter

• atomic weight

• molecular weight (Formula Weight)

Molarity

# moles AMolarity => M = -------------------

# liters solutionor

# millimoles AMolarity => M = -------------------------

# milliliters solution

Useful Algebraic Relationships

wt A (g)# mol A = -----------------

fw A (g/mol)

# mol A = V (L) x M (mol A/L soln)

orwt A (mg)

# mmol A = -----------------fw A (g/mol)

# mmol A = V (mL) x M (mmol A/mL soln)

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Types of Solutions

• strong electrolyte

• weak electrolyte

• non-electrolyte

p-Functions

pX = - log10[X]

examples:

pH

pOH

pCl

pAg

Percent Composition

wt of a solutew - w% = -------------------- X 102 %

wt of solutionvol of a solute

v - v% = -------------------- X 102 %vol of solutionwt of a solute

w - v% = --------------------- X 102 %vol of solution

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Parts per Million (ppm)

wt of a solutecppm = ------------------- X 106

wt of solution

Remember:1 ppm = 1 μg (solute)/mL (solution) = 1 mg/LAssuming: solution density = 1.0 g/mL(it is true for most of the diluted aqueous solutions)

Practice: What is the molar concentration of 585 ppm NaCl? (10.0 mM)

Parts per Billion (ppb)

wt of a solutecppb = ------------------- X 109

wt of solution

Textbook Website:

http://www.thomsonedu.com/