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The University of Southern MississippiDepartment of Chemistry and BiochemistryCHE 311 (311L)Analytical Chemistry (Lab)Instructor: Dr. Wujian MiaoLab Coordinator: Tina Masterson1About this courseCHE 311-Analytical ChemistryCombined syllabus with schedulescan be downloaded from:http://www.usm.edu/electrochem Teaching 3. Spring, Summer and Fall Semesters LoginArea UserID “CHE311” and Password “Summer2008”2Fall 2019Final ACS exam warranties:If the student has missed no more than3 lectures during the semester, hasturned in all assignments and attendedall regular exams, the following“warranties” will applyQs answeredcorrectly out of 50National %ileFinal grade noworse than 3485A 3072B 2758C 2547DGradeACS CBBA31
Few Tips For Success in the Class actively attending every class and take goodnotes improving your math (good math is absolutelyessential) completing all homework and study textbook Taking CHE 311L VERY Seriously asking questions4Final grade distribution of fall 12.12NA13.0333100100ABCDF NA5Final grade distribution of fall 050ABCDF62
Final grade distribution of fall 201950.00Overall Class 5.000.00Overall23100ABCDFWD7Survey and Q&A8Textbook for this course:Fundamentals ofAnalytical Chemistry(9th Ed, 2014)Skoog-West-Holler-Crouch93
Chapter 1Introduction ofAnalytical Chemistry10What is Analytical Chemistry? “The study of methods for determining thecomposition of substances.”The sample could contain:(1) Ca2 , Na , or K ionsOR(2) A urine sample from apotentially pregnant womanAn unknown sample solutionYour job:To tell what is the sample or isthe woman pregnant?11Analytical ChemistryWhat is the sample?IdentificationQualitative AnalysisCa2 How much is X in the sample?QuantitationQuantitative Analysis (EDTA titration)Flame test(Brick Red)EDTA-CaComplexEmission Spectroscopy (Spectroscope)124
Pregnancy Test StripHormone(protein)13Analytical Chemistry “The study of methods for determining thecomposition of substances.” “The science of extraction, identification, andquantitation of an unknown sample.”Two Areas: Qualitative Analysis (what?) Quantitative Analysis (how much?)14Roles of Analytical Chemistry ForensicsArchaeologyFoodPharmacyMedicine155
General Steps in a Chemical AnalysisChocolate(33% fat, 47% sugar, )Bitter taste?NO bromineFrom Greek“Food of gods”Both in chocolate161. Formulating the Question2. Selecting Analytical Procedures/MethodsDefining the problem: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 causeinterference?5. What are the physical and chemical properties ofthe sample matrix?6. How many samples are to be analyzed?17Numerical Criteria for SelectingAnalytical Methods1. Precision2. Accuracy3. Bias4. Sensitivity5. Detection Limit6. Concentration Range (Dynamic range)7. Selectivity186
Other Characteristics to BeConsidered in Method of Choice1. Speed (point of care diagnostic testing)2. Ease and Convenience3. Cost and availability of instrument4. Per-sample cost193. SamplingAliquot—a portion of alarger whole,especially asample takenfor chemicalanalysis orother eterogeneousMaterial217
4. Sample PreparationPetroleum ether(a mixture of alkanes)Petroleum EtherFat Remove fat from chocolate22Extraction of theobrominefrom chocolate with waterSolubility: 330 mg/L in water235. Analysis248
6. Reporting and Interpretation7. Drawing Conclusions25The International System of Units (SI)26SI (International System of Units) PrefixesEspecially useful in this coursemegaM106kilok103centic10-2millim10-3micro 10-6nanon10-9picop10-12279
Modern Anal TechLOD28Solution Terminology solutesolventaqueous solutionliteratomic weightmolecular weight (Formula Weight)29Molarity# moles AMolarity (M): c ------------------# liters solutionor# millimoles AMolarity (M): c ------------------------# milliliters solution3010
Useful Algebraic Relationshipswt A (g)# mol A ----------------fw A (g/mol)# mol A V (L) x C (mol A/L soln)orwt A (mg)# mmol A ----------------fw A (g/mol)# mmol A V (mL) x C (mmol A/mL soln)31Percent Compositionwt of a solutew - w% -------------------- 102 %wt of solutionvol of a solutev - v% -------------------- 102 %vol of solutionwt of a solutew - v% --------------------- 102 %vol of solution32Parts per Million (ppm)wt of a solutecppm ------------------- 106wt of solutionRemember: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 ppmNaCl? (10.0 mM)3311
Parts per Billion (ppb)wt of a solutecppb ------------------- 109wt of solution34p-FunctionspX - log10[X]examples:pHpOHpClpAg3512
Analytical Chemistry 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? “The study of methods for deter
