ASTM_E_1840_-_96_2014.pdf

Designation:E184096(Reapproved 2014)Standard Guide forRaman Shift Standards for Spectrometer Calibration1This standard is issued under the fixed designation E1840;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers Raman shift values for commonliquid and solid chemicals that can be used for wavenumbercalibration of Raman spectrometers.The guide does notinclude procedures for calibrating Raman instruments.Instead,this guide provides reliable Raman shift values that can be usedas a complement to low-pressure arc lamp emission lineswhich have been established with a high degree of accuracyand precision.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 Some of the chemicals specified in this guide may behazardous.It is the responsibility of the user of this guide toconsult material safety data sheets and other pertinent infor-mation to establish appropriate safety and health practices anddetermine the applicability of regulatory limitations prior totheir use.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E131 Terminology Relating to Molecular SpectroscopyE1683 Practice for Testing the Performance of ScanningRaman Spectrometers3.Terminology3.1 DefinitionsTerminology used in this guide conformsto the definitions set forth in Terminology E131.4.Significance and Use4.1 Wavenumber calibration is an important part of Ramananalysis.The calibration of a Raman spectrometer is performedor checked frequently in the course of normal operation andeven more often when working at high resolution.To date,themost common source of wavenumber values is either emissionlines from low-pressure discharge lamps(for example,mercury,argon,or neon)or from the non-lasing plasma lines ofthe laser.There are several good compilations of these well-established values(1-8).3The disadvantages of using emissionlines are that it can be difficult to align lamps properly in thesample position and the laser wavelength must be knownaccurately.With argon,krypton,and other ion lasers commonlyused for Raman the latter is not a problem because lasingwavelengths are well known.With the advent of diode lasersand other wavelength-tunable lasers,it is now often the casethat the exact laser wavelength is not known and may bedifficult or time-consuming to determine.In these situations itis more convenient to use samples of known relative wave-number shift for calibration.Unfortunately,accurate wavenum-ber shifts have been established for only a few chemicals.Thisguide provides the Raman spectroscopist with average shiftvalues determined in seven laboratories for seven pure com-pounds and one liquid mixture.5.Raman Shift Standards5.1 Reagents and MethodologyRaman shifts were mea-sured in seven laboratories for the following eight materials:1This guide is under the jurisdiction of ASTM Committee E13 on MolecularSpectroscopy and Separation Science and is the direct responsibility of Subcom-mittee E13.08 on Raman Spectroscopy.Current edition approved May 1,2014.Published June 2014.Originaly approvedin 1996.Last previous edition approved in 2007 as E1840 96(2007).DOI:10.1520/E1840-96R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthe text.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 CompoundSourceNaphthaleneMallinckrodt41,4-Bis(2-methylstyryl)benzene(a laser dye)Aldrich5SulfurAldrich550/50(v/v)toluene/acetonitrileMallinckrodt44-Acetamidophenol6Aldrich5BenzonitrileAldrich5CyclohexaneMallinckrodt4PolystyreneAldrich55.1.1 The eight materials were selected to cover a widewavenumber range(from 85 to 3327 cm1)for both solids andliquids.They have no known polymorphs,and several batcheswere examined.All of the chemicals are readily available athigh purity from commercial sources such as Aldrich.5Six ofthe laboratories in the study used FT-Raman spectrometers;one used a scanning Raman system;and one employed amultichannel spectrometer.The shift values were determinedindependently by each laboratory;only an approximate spec-trum without peak frequencies was provided as a guide.Nowavenumber calibration procedure was recommended,buteach