203-Introductory Lecture-1-jan-6-2010-PDF

203-Introductory Lecture-1-jan-6-2010-PDF - 1 INSTRUMENTAL...

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1 INSTRUMENTAL METHODS OF ANALYSIS In this course we will be looking at several instrumental methods of analysis. They may be classified into three main groups of analytical methods. SPECTROSCOPIC METHODS OF ANALYSIS UV-VIS - molecular - emission - absorption* - fluorescence - phosphorescence - atomic - emission ELECTROMETRIC METHODS OF ANALYSIS ELECTROCHEMICAL - cells* - potentiometry* - coulometry - voltammetry CHROMATOGRAPHIC METHODS OF ANALYSIS Column - GC* - HPLC Planar - paper - TLC
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2 CHEMICAL ANALYSIS INFORMATION FROM SYSTEMS System (under study) - contains the analyte about which information, e.g., identity, mass, concentration, etc., is to be obtained - the information is inherent in the physical and/or chemical characteristics of the analyte - the information obtained may be interpreted, manipulated, and/or used, as required by the analyst Analytical instrument - is used to obtain information about the analyte (from the system) - thus it may be viewed as a device that communicates information from the analyte to the analyst - to obtain this information, it is necessary to stimulate the analyte in some manner, e.g., with electromagnetic, electrical, mechanical, and/or nuclear energy, among many - to elicit a response from the analyte Data domains - various modes of encoding information, i.e., transforming information from one system of information to another - concept is used to develop a classification scheme to analyse and explain the measurement process, i.e., to examine the flow of information inherent in the physical and chemical characteristics of the analyte to a readout, e.g., meter pointer, chart recorder, or digital device - two main classifications: non-electrical and electrical (domains) - the measurement process begins and ends in the non- electrical domain - non-electrical domain contains the following types of measurements: physical and chemical, scale position, number (digital measurement) - electrical domain contains the following types of measurements: analog (current, voltage, and charge), time (frequency, pulse width, and phase), and digital (count, serial, and parallel)
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3 The measurement - ultimate objective is that the final numerical result is some function of the relevant physical or chemical property being measured - can be represented as a series of inter-domain conversions - begins and ends in the non-electrical domain because the physical and chemical characteristics of the analyte reside in this domain - may be entirely in the non-electrical domain, e.g., mass, length, temperature, colour. There is no encoding in the electrical domain. - may be encoded in the electrical domain through an input transducer - the read-out device that converts the data in the electrical domain to the non-electrical domain is called the out-put transducer - the mathematical relationships between the input transducer and the electrical signal, and the electrical signal and the out-put are called the transfer functions of the transducers
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4 Detection system - refers to the entire instrument used as above Detectors, transducers, and sensors
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This note was uploaded on 12/22/2011 for the course CHY 203 taught by Professor Dr.naranjit during the Spring '11 term at Ryerson.

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203-Introductory Lecture-1-jan-6-2010-PDF - 1 INSTRUMENTAL...

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