ASTM E932-89(R2021) pdf free download

ASTM E932-89(R2021) pdf free download.Standard Practice for Describing and Measuring Performance of Dispersive Infrared Spectrometers
1. Scope
1.1 This practice covers the necessary information to qualify dispersive infrared instruments for specific analytical applications, and especially for methods developed by ASTM International. 1.2 This practice is not to be used as a rigorous test of performance of instrumentation. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Significance and Use
4.1 This practice is intended for all infrared spectroscopists who are using dispersive instruments for qualitative or quan- titative areas of analysis. 4.2 The purpose of this practice is to set forth performance guidelines for testing instruments used in developing an analytical method. These guidelines can be used to compare an instrument in a specific application with the instrument(s) used in developing the method. 4.3 An infrared procedure must include a description of the instrumentation and ofthe performance needed to duplicate the precision and accuracy of the method.
5. Apparatus
5.1 For the purposes of this practice, dispersive instruments include those employing prisms, gratings, or filters to separate infrared radiation into its component wavelengths. 5.2 For each new method, describe the apparatus and instrumentation both physically and mechanically, and also in terms of performance as taught in this practice. That is, the description should give numerical values showing the fre- quency accuracy and the frequency and the photometric precision. State the spectral slit width maximum or slit width program ifone is used. Where possible, state the maximum and minimum resolution if those data are a part of the instrument display. Show typical component spectra as produced by the instrument to establish the needed resolution. 5.3 If a computer program is used, describe the program. Include the programming language and availability, or whether the program is proprietary to a manufacturer.
7. Parameters in Spectroscopy
7.1 Dispersive infrared spectrometers have a source of quasi-monochromatic radiation together with a photometer for measuring relative radiant power. Accurate spectrometry in- volves a large number of interrelated factors that determine the quality of the radiant power passing through a sample and the sensitivity and linearity with which this radiant power can be measured. Assuming proper instrumentation and its use, the instrumental factors responsible for inaccuracies in spectrom- etry are resolution, linearity (Practices E168), stray radiant power (Test Method E387), and cell constants (Practice E1252). Rigorous measurement of these factors is beyond the scope of this practice, and a more practical approach is described for the accessible factors.
8. Instrument Operation
8.1 The analyst selects the proper instrumental operating conditions in order to get satisfactory performance (1-3). 4 Because instrument design varies, the manufacturer’s recom- mendations are usually best. A record of operating conditions should be kept so that data can be duplicated by future users. 8.2 In addition to operating conditions, the following should be checked and recorded: 8.2.1 Ambient temperature, 8.2.2 Pen response time, 8.2.3 Scanning speed, N OTE 1—In some instruments these functions are integrated in the scan modes. 8.2.4 Noise level, and 8.2.5 Mechanical repeatability. 8.3 Each of the above factors is important in the measure- ment of analytical wavenumber and photometric data. There is usually some lag between the recorded reading and the correct reading. Proper selection of operating conditions and good, reproducible, sample handling techniques minimize these ef- fects or make the effects repeatable. For example: 8.3.1 Variation in temperature of the monochromator or sample may cause changes in wavenumber precision and accuracy.