西北师范大学：《仪器分析》课程教学资源（PPT课件）Chapter 01 preface.ppt_大学文库

INSTRUMENTAL ANALYSIS e-COURSE NOTE By WU YANG

TEXTBOOKS: ●Instrumental Analysis，Zhu Ming-hua，Higher Education Press(3rd)(Textbook for 21th Century), Beijing, 2001(in Chinese) ● Modern Analytical Chemistry, David Harvey, McGraw-Hill, Inter. Ed., Singapore, 2000 ● Contemporary Instrumental Analysis, K.A.Rubinson, J.F. Rubinson, Science Press & Prentice Hall, Inc., Beijing, 2000(影印版）

HOW to study this course ●熟悉仪器分析课程各章节的编排规律，各种方法的意义及特点、各种分析方法的联系和区别。 ●充分发挥学生的能动作用，做到师生互动；反馈渠道通畅。 ●协调好课堂学习与课后复习、课前预习的关系。 ●遵守课堂秩序和课堂纪律

Teaching Purpose ●仪器分析是化学与化学工程类专业必修的基础课之一。通过本课程的学习 ●要求学生掌握: Principle of instrumental analytical methods in common use and simple setup； ●要求学生初步具有 An ability to develop appropriate analytical procedure according to the analytical purpose based on the advantage and application fields of different instrumental analyses studied

Chapter 1 PREFACE Description of Validation Parameters Accuracy Closeness of agreement between the value obtained by the method and the true value. Precision Expresses the closeness of agreement between a series of measurements obtained from multiple sampling. Precision is often expressed as the standard deviation or Relative standard deviation of replicate measurements (later on RSD). Note that a method can be precise, but not accurate (so all your measurements may be close together, but the result is wrong)

Specificity The ability to measure the analyte in the presence of components which we expect to be present in the sample matrix. So if you are determining the concentration of Iron and Chromium in water by UV/Vis spectroscopy, if there are small amounts of Fluoride and Chloride in the sample, will that affect your measurement? Detection Limit The lowest amount of analyte in a sample that can be detected, but not necessarily quantitated. Usually the lowest limit is evaluated as the Signal-to-Noise ratio that is equivalent to 3 times the standard deviation of the noise ( S/N = 3s)

Quantitation Limit The lowest amount of analyte in a sample that can be quantitated with suitable precision and accuracy. Usually the Quantitation limit is evaluated as the Signal-toNoise ratio that is equivalent to 10 times the standard deviation of the noise ( S/N = 10s). Continued Linearity The range of concentrations of analyte for which the procedure provides test results that are in direct correlation to the amount of analyte in the sample. Range The same as linearity, except the test results must also be accurate and precise (over the concentrations tested). Robustness (Ruggedness) Measure of an method’s capacity to remain unaffected by small but deliberate variations in method parameters

Continued Analysis, Assay, Determination, Measurement, Identification These phrases are usually used to describe one process to determine the concentration of the analytes in a sample Protocol, operation, method, procedure, measure, technique These phrases means a method to evaluate the concentration of the analytes in a sample

分析化学—化学分析、仪器分析 ●Analytical chemistry A subject to study chemical composition, structure and state of substances including chemical analysis and instrumental analysis. ●Chemical analysis A method to determine chemical composition and content of the analytes in a sample based on chemical reaction and stoichiometric relation of teactants usually requiring chemical reagents, balance and glassware. ● Instrumental analysis is an analytical method based on determination of physical and physical chemical properties which needs some complicated apparatus. ●仪器分析的产生为分析化学带来革命性的变化，仪器分析是分析化学的发展方向

Characteristics of Instrumental Analyses （与化学分析比较） ●Higher sensitivity, detection limit down to lower level 如样品用量由化学分析的mL、mg级降低到仪器分析的g、L级，甚至更低。适合于微量（micro-)、痕量(trace)和超痕量 (ultratrace)成分的测定。 ● Higher selectivity 很多的仪器分析方法可以通过选择或调整测定的条件，使共存的组分测定时，相互间不产生干扰。 ● Simpler operation, faster assay & easy of automation ● Poorer relative error 化学分析一般可用于常量和高含量成分分析，准确度较高，误差小于千分之几。多数仪器分析相对误差较大，一般为5%，不适用于常量和高含量成分分析。 ● More expensive apparatus