analytical chemistry (ii)...

Analytical Chemistry (II) ---------------------------------------------------------------------------------- Instructor: Office: 524 (x-66406)Lab: 424 (x-661406) --------------------------------------------------------------------------------- Course contents: 1.Basic concepts of instrumental analysis (R1;ch. 5; R2:ch. 1) 2.Analytical separations (R1:ch. 23-26; R2: ch. 26-30) Mid-term 5/4 19:00 50% 3. Spectrochemical analysis (R1;ch. 19-22; R2: ch. 6-10, ch. 13-14) Final exam. 6/22 19:00 40% References: 1.Quantitative chemical analysis 6th ed.by Daniel C. Harris. 2.Principles of instrumental analysis th ed. By Skoog/Holler/Crouch

What Is Green Chemistry? Green chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. The Twelve Principles of Green Chemistry** 1.Prevention: It is better to prevent waste than to treat or clean up waste after it has been created. 2. Atom Economy: Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. 3. Less Hazardous Chemical Syntheses: Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment. 4. Designing Safer Chemicals: Chemical products should be designed to effect their desired function while minimizing their toxicity.

5. Safer Solvents and Auxiliaries: The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used. ( : ) 6. Design for Energy Efficiency: Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure. 7.Use of Renewable Feedstocks: A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable. 8. Reduce Derivatives: Unnecessary derivatization (use of blocking groups, protection/ deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste.

9. Catalysis: Catalytic reagents (as selective as possible) are superior to stoichiometric reagents. 10. Design for Degradation: Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment. 11. Real-time analysis for Pollution Prevention: Analytical methodologies need to be further developed to allow for real-time, in- process monitoring and control prior to the formation of hazardous substances. 12. Inherently Safer Chemistry for Accident Prevention: Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions, and fires. ( )

Extraction of Metal Ions with RTIL Extraction of Metal Ions with RTIL Extraction of Metal Ions with RTIL Extraction of Metal Ions with RTIL RTIL , , RTIL( 1-butyl-3- methylimidazolium hexafluorophosphate, [BMIM][PF 6 ]) RTIL . 1.Guor-Tzo Wei*, Zusing Yang, Chao-Jung Chen, Anal. Chimica, Acta 2003, 488(2), 183. 2.Guor-Tzo Wei*, Jin-Chu Chen, Zusing Yang, J. Chin. Chem. Soc. 2003, 50, 1123.

- : . - : a. supercritical fluid CO 2 b. ionic liquid(IL)

Presidential Green Chemistry Challenge Awards http://www.epa.gov/greenchemistry/ Mission: To promote innovative chemical technologies that reduce or eliminate the use or generation of hazardous substances in the design, manufacture, and use of chemical products. 1996: Alternative Synthetic Pathways Award: Monsanto Company, The Catalytic Dehydrogenation of Diethanolamine Alternative Solvents/Reaction Conditions Award: Dow Chemical The Development and Commercial Implementation of 100 Percent Carbon Dioxide as an Environmentally Friendly Blowing Agent f or the Polystyrene Foam Sheet Packaging Market Designing Safer Chemicals Award: Rohm and Haas Designing an Environmentally Safe Marine Antifoulant Small Business Award: Donlar Corporation Production and Use of Thermal Polyaspartic Acid Academic Award : Prof. Mark Holtzapple, Texas A&M Univ. Conversion of Waste Biomass to Animal Feed, Chemicals, and Fuels

What is a Room Temperature Ionic Liquid (RTIL)? (Room Temperature Molten Salt) Liquid salt consisting of at least one organic component (cation or anion) with melting point below room temperature Properties: Negligible vapor pressure High thermal stability (~250-400C) High viscosity Hydrophobic or hydrophilic Dissolve many organic, organometallic, and inorganic compounds RTILs are regarding as Green solvents

Ethyl ammonium nitrate (EtNH + 3 )(NO - 3 ), which has a melting point of 12C, was first described in 1914. P. Walden, Bull. Acad. Imper. Sci. (St. Petersburg) 1800 (1914). Osteryoung & Wilks, late1970, chloroaluminate salts in electrochemistry Sneddon & Hussey, 1980, groups chloroaluminate salts in electrochemistry and organometallic researches. After 1990, used as solvents for synthesis Late 2000, the application in separation

Pure Appl. Chem., 2000, 72, 22752287

RTIL Structures Cations Anions PF 6 - SbF 6 - BF 4 - CF 3 SO 3 - (TfO) Cl - N(CF 3 SO 2 ) 2 - (NTf 2 ) 1-butyl-3-methylimidazolium, BMIM, C 4 MIM R: methyl; R : n-butyl 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ] 1-octyl-3-methylimidazotetrafluoroborate [OMIM][BF 4 ]

General syntheses of ionic liquid: Green Chemistry, 2003. 5. 181-186.

Effect of the nature of anion on physical properties of BMIM salt ----------------------------------------------------------------------------------- Anionm.p. d Viscosity Conductivity o C g/cm 3 cP (20 o C) S/m ---------------------------------------------------------------------------------- BF 4 - -82(g) 1.17 233 0.17 PF 6 - -8 1.36 312 0.14 Cl - 65 1.10 solid solid CF 3 COO - ~-40(g) 1.21 73 0.32 CF 3 SO 3 - 16 1.29 90 0.37 (CF 3 SO 2 )N - -4 1.43 52 0.39 C 3 F 7 COO - ~-40(g) 1.33 1820.10 C 4 F 9 SO 3 - 20 1.47 373 0.045 ---------------------------------------------------------------------------------- (g) Glass transition P.S. viscosity of water 1 cP.

Dissolution of Cellulose with Ionic Liquids R.P. Swatloski, R.D. Rogers, et al. J.A.C.S. 124 (2002) 4974.

Room-temperature ionic liquids: a novel versatile lubricant Chengfeng Ye, Weimin Liu, Yunxia Chen and Laigui Yu, Chem. Commun., 2001, (21), 2244 - 2245 Alkylimidazolium tetrafluoroborates are promising versatile lubricants for the contact of steel/steel, steel/aluminium, steel/copper, steel/SiO2, Si3N4/SiO2, steel/Si(100), steel/sialon ceramics and Si3N4/sialon ceramics; they show excellent friction reduction, antiwear performance and high load-carrying capacity

Uses of RTILs in Anal. Chem. Novel solvents in liquid-liquid or micro extractions Run buffer additives in CE Matrixes in Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry Stationary phases in gas-liquid chromatography

Illustration of various equilibra involved in metal ion extraction with ionic liquid. Extraction of Metal Ions with RTIL Extraction of Metal Ions with RTIL Extraction of Metal Ions with RTIL Extraction of Metal Ions with RTIL

colorlessmetal complex (red) dithizone

+ + + Cu 2+ 2H + + + + 2 2 2 Green Blue Violet Yellow Orange Red Dithizone Oxine PAN

The pH value effect on the extraction of lead ion with dithizone in ( ) ionic liquid, ( ) chloroform.

Comparing the extraction of copper ions with ionic liquid and dichloromethane with PAN

The effect of pH value on the extraction efficiencies of metal ions with dithizone by IL.

The effect of pH value on the extraction efficiencies of metal ions with PAN by IL.

Hg 2+ Zn 2+ Pb 2+ Ca 2+ Cr 3+ Mn 2+ Cd 2+ As 5+ Co 2+ Ag + The effect of 100 ppm cation on the extraction of 5 ppm Cu 2+ with dithizone

SCN - citrate Cl - CO 3 2- PO 4 3- CH 3 COO - The effect of 100 ppm anion on the extraction of 5 ppm Cu 2+ with dithizone

SCN - citrate Cl - CO 3 2- PO 4 3- CH 3 COO - The effect of 100 ppm anion on the extraction of 5 ppm Cu 2+ with PAN

TimesTheoretical Value (ppm) Experimental Value (ppm) Recovery ( ) 510.00 100 1020.00 100 2040.0038.2095.5 2550.0045.7595.8 50100.0099.0099.0 Preconcentration of Pb 2+

Metal ion s pHE% Cu(II) Cd(II) 2.7456 0 Ag(I) Cd(II) 1.4389.48 0 Cd(II) Ca(II) 7.0887.2 0 (a) Separation of different metal ions; (b) Reproducibility of Cadmium ions with reusal [C 4 MIM][PF 6 ] pHE (%) 3.9843.16 3.8938.42 3.9344.74 4.0143.68 3.9942.63 4.0244.21 3.9946.32 Average = 43.31% RSD = 5.69% (a) (b)

1. (10%) A least square linear regression of the standards for an instrument obtained : Y = 2.70 + 5.23 X, where X is the concentration (in ng/mL) of an analyte. The standard deviation of determination S is 0.043. Find the limit of detection. 2. (10 %) A known mixture of compounds A and B gave the following HPLC results: CompoundConc. (mg/mL in mixture)Peak area (cm 2 ) A1.0310.86 B1.164.37 A solution was prepared by mixing 12.29 mg of B plus 10.00 mL of unknown containing just A, and diluting to 25.00 mL. Peak area of 5.79 and 6.28 cm 2 were observed for A and B, respectively. Find the concentration of A (mg/mL) in the unknown.

1. (10 %) A known mixture of compounds A and B gave the following HPLC results: CompoundConc. (mg/mL in mixture)Peak area (cm 2 ) A1.0310.86 B1.164.37 A solution was prepared by mixing 12.29 mg of B plus 10.00 mL of unknown containing just A, and diluting to 25.00 mL. Peak area of 5.79 and 6.28 cm 2 were observed for A and B, respectively. Find the concentration of A (mg/mL) in the unknown.

analytical chemistry (ii)...

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