ASTM_E_1303_-_95_2010.pdf

Designation:E130395(Reapproved 2010)Standard Practice forRefractive Index Detectors Used in Liquid Chromatography1This standard is issued under the fixed designation E1303;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 practice covers tests used to evaluate the perfor-mance and to list certain descriptive specifications of arefractive index(RI)detector used as the detection componentof a liquid chromatographic(LC)system.1.2 This practice is intended to describe the performance ofthe detector both independent of the chromatographic system(static conditions,without flowing solvent)and with flowingsolvent(dynamic conditions).1.3 The values stated in SI units are to be regarded as thestandard.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:2E386 Practice for Data Presentation Relating to High-Resolution Nuclear Magnetic Resonance(NMR)Spec-troscopy3.Significance and Use3.1 Although it is possible to observe and measure each ofseveral characteristics of a detector under different and uniqueconditions,it is the intent of this practice that a complete set ofdetector test results should be obtained under the same oper-ating conditions.It should also be noted that to specifycompletely a detectors capability,its performance should bemeasured at several sets of conditions within the useful rangeof the detector.3.2 The objective of this practice is to test the detector underspecified conditions and in a configuration without an LCcolumn.This is a separation independent test.In certaincircumstances it might also be necessary to test the detector inthe separation mode with an LC column in the system,and theappropriate concerns are also mentioned.The terms and testsdescribed in this practice are sufficiently general so that theymay be adapted for use at whatever conditions may be chosenfor other reasons.4.Noise,Drift,and Flow Sensitivity4.1 Descriptions of Terms Specific to This Standard:4.1.1 short term noisethis noise is the mean amplitude inrefractive index units(RIU)for random variations of thedetector signal having a frequency of one or more cycles perminute.Short term noise limits the smallest signal detectableby an RI detector,limits the precision attainable,and sets thelower limit on the dynamic range.This noise corresponds toobserved noise of the RI detector only.(The actual noise of theLC system may be larger or smaller than the observed value,depending upon the method of data collection,or signalmonitoring of the detector,since observed noise is a function ofthe frequency,speed of response and the band width of therecorder or other electronic circuit measuring the detectorsignal.)4.1.2 long term noisethis noise is the maximum amplitudein RIU for random variations of the detector signal withfrequencies between 6 and 60 cycles per h(0.1 and 1.0 cyclesper min).It represents noise that may be mistaken for alate-eluting peak.This noise corresponds to the observed noiseonly and may not always be present.4.1.3 driftthe average slope of the long term noise enve-lope expressed in RIU per hour as measured over a period of1 h.4.1.4 staticrefers to the noise and drift measured underconditions of no flow.4.1.5 dynamicrefers to the noise and drift measured at aflow rate of 1.0 mL/min.4.1.6 flow sensitivitythe rate of change of signal displace-ment(in RIU)vs flow rate(in mL/min)resulting from stepchanges in flow rate calculated at 1 mL/min as described in4.3.12.4.2 Test Conditions:1This practice is under the jurisdiction of ASTM Committee E13 on MolecularSpectroscopy and Separation Science and is the direct responsibility of Subcom-mittee E13.19 on Separation Science.Current edition approved Nov.1,2010.Published November 2010.Originallyapproved in 1989.Last previous edition approved in 2005 as E1303 95(2005).DOI:10.1520/E1303-95R10.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2.1 The same test solvent must be used in both sample andreference cells.The test solvent used and its purity should bespecified.Water equilibrated with the laboratory atmospherecontaining minimum impurities is the preferred test solvent formeasuring noise and drift.Water for this purpose(preferablypurified by distillation,deionizati