Instrumental Analysis CHEM - 4400

Intro to Instrumental Analysis Chapter 1 Classification of Analytical Methods Qualitative instrumental analysis is that measured property indicates presence of analyte in matrix. Quantitative instrumental analysis is the magnitude of measured property is proportional to concentration of analyte in matrix.

Another Classification Classical Methods Titrations Gravimetric analysis Instrumental Methods Based on measurements of properties of analyte Phenomena known for years Recent growth due to electronics and computers

Characteristic Property Instrumental Method Emission of radiation fluorescence, phosphorescence, X-ray Adsorption of radiation NMR, EPR, UV-vis, IR Scattering of radiation Raman, turbidimetry Refraction of radiation Refractometry Diffraction of radiation X-ray (XRPD) Rotation of radiation Polarimetry, optical rotary dispersion Electrical potential Potentiometry Electrical charge Coulometry Electrical current Amperometry, polarography Electrical resistance Conductometry Rate of reaction Kinetic methods Mass-to-charge ratio Mass spectrometry

Precision – A measure of the reproducibility of a measurement Precision – A measure of the reproducibility of a measurement. Accuracy – A measure of how close a measured value is to the “true value” Sensitivity – Ability to discriminate between small differences in analyte concentration Calibration sensitivity – Slope of calibration curve at concentration of interest Analytical sensitivity () – m/ss (slope/STDEV of measurement)

Detection Limit – minimum concentration of analyte that can be detected at a know confidence level. Signal Detection Limit – minimum signal that can be distinguished from the blank.