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1、Types of instrumental methods: Atomic Spectrometry（Atomic Absorption、Atomic Emission、Atomic Fluorescence） 、 Molecular Spectrometry（Ultraviolet-Visible Spectroscopy 、Infrared Radiation 、Nuclear Magnetic Resonance、Mass spectrometry） 、Chromatography （Gas、Liquid Chromatography ） 、Electroananlytical Chem
2、istry（Potentiometry、Coulometry、Voltammetry） Use of instruments for qualitative and quantitative energy source- system under study-analytical information(always by peaks) Selection of a suitable methodUnderstanding of the problem 、Knowledge of the performance characteristics of various instruments(Qu
3、antitative:Precision（random error） 、Bias(systematic) 、 Detection Limit(Cm=(Sm-S bl )/m、Sm=S bl +ks bl ,k=3)、Sensitivity(S=mc+S bl 、=m/Ss)、Dynamic Range(Ll=10S bl 、Ul= A deviation of 5% from linearity.)、Selectivity（free from interference by other species ）. Qualitative:Speed、Operation skill required、
4、Per-sample cost、Ease Introduce the internal standard into both sample and calibration standards in a reproducible way. The internal standard should provide a signal that is similar to the analyte signal in most ways but sufficiently different so that the two signals are distinguishable by the instru
5、ment be absent from the sample matrix so that the only source of the standard is the added amount not change the analyte signal） Spectroscopy: Study of interaction between radiation (or other forms of energy)and matter Spectrometry: Analytical methodsbased on atomic and molecular spectroscopy Electr
6、onic states, Vibrational states, Rotational states(atoms or ions only involves changes in ES 因此 line spectra;molecules 三个都有,band spectra) Types of analytical spectroscopy: Emission (with flames, arcs, sparks, and plasmas)、 Chemiluminescence and Bioluminescence、Absorption 、Fluorescence and Phosphores
7、cence、Scatterin Excitation needs energy!Particle bombardment;Electrical currents;Fluorescence;Heat Absorption of radiation :Atomic absorption(Exciation can occur only by an electronic process in which one or more of the electrons of atom are raised to a high energy level);high-resolution instrument;
8、low-resolution instrument;solvent effects on molecular absorption.Applications of interactions of radiation and matter in spectroscopy: Spectroscopists use the interactions of radiation with matter to obtain information about a sample. The sample is usually stimulated by applying energy in the form
9、of heat, electrical energy, light, particles, or a chemical reaction. Prior to applying the stimulus, the analyte is predominantly in its lowest energy state, or ground state. The stimulus then causes some of the analyte species to undergo a transition to a higher energy, or excited state. We acquir
10、e information about the analyte by measuring the electromagnetic radiation emitted as it returns to the ground state or by measuring the amount of electromagnetic radiation absorbed or scattered as a result of excitation. Continuum Spectra:Produced when solid are heated to incandescence;Blackbody Ra
11、diation (Thermal Radiation) P=kc;S=kP Components of Optical Instruments:Sources(a stable source of radiant energy. To he suitable for spectroscopic studies, a source must generate a heam with sufficient radiant power for easy detection and measurement. In addition. its output power should be stable
12、for reasonable periods.);Sample Holders(a transparent container for holding the sample Must:contain the sample without chemical interaction;be more-or-less transparent to the wavelengths of light in use;be readily cleaned for reuse;be designed for the specific instrument of interestquartz 190-3000 n
13、m;glass 300-900 nm;NaCl and KBr much higher wavelengths (IR range);Wavelength Separators(A device isolating a restricted range of the spectrum for the measurement. Filters and Monochromators);Detectors(Transducers:respond to photons(UV,visible and near-infrared radiation)/heat(infrared radiation)(wh
14、ich converts radiant energy to a usable electrical signal.); Signal processor and readout(which display the transduced signal on a meter scale,a computer screen,a digital meter or another recording device) Monochromators: This radiation enters the monochromators via a narrow rectangular opening, or
15、SUI; is collimated; and then strikes the surface of the dispersing element at an angle. For the grating monochromator, angular dispersion of the wavelengths results from diffraction, which occurs at the reflective surface; for the prism, refraction at the two faces results in angular dispersion of t
16、he radiation, as shown. Al and one for A,). By rotating the dispersing element,one band or the other can be focused on the exit slit. Slits: Entrance slits control theintensityof light entering the monochromator and help control the range of wavelengths of light that strike the grating.Exitslits help select the range of wavelengths that exit the monochromator and strike the detector.Development history of AAS: Discovery of atomic absorption
