ASTM_F_2714_-_08_2013.pdf

Designation:F271408(Reapproved 2013)Standard Test Method forOxygen Headspace Analysis of Packages Using FluorescentDecay1This standard is issued under the fixed designation F2714;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 test method covers a procedure for determinationof the oxygen concentration in the headspace within a sealedpackage without opening or compromising the integrity of thepackage.1.2 This test method requires that chemically coated com-ponents be placed on the inside surface of the package beforeclosing.1.3 The package must be either transparent,translucent,or atransparent window must be affixed to the package surfacewithout affecting the packages integrity.1.4 As this test method determines the oxygen headspaceover time,the oxygen permeability can easily be calculated asingress per unit time as long as the volume of the container isknown.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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.Summary of Test Method2.1 Chemically coated components(dots)are affixed to theinside surface of the package to be tested.2.2 The package is gas flushed to a reduced level of oxygeneither manually or by subjecting the package to a fillingoperation.2.3 Apulsing light source is directed through the package atthe chemically treated dot(the package must be transparent,translucent or contain a window through which the light canpass).2.4 The fluorescent response from the dot is monitored andthe decay rate determined.2.5 The internal oxygen content of the package is deter-mined by comparing the measured decay rate to the decay rateobserved with known oxygen concentrations.3.Significance and Use3.1 The oxygen content of a packages headspace is animportant determinant of the packaging protection afforded bybarrier materials.The package under test is typically MAP(modified atmosphere packaging)packaged.3.2 Oxygen content is a key contributor to off-flavors andspoilage of various products,such as chemicals,food andpharmaceuticals.3.3 The method determines the oxygen in a closed packageheadspace.This ability has application in:3.3.1 Package Permeability StudiesThe change of head-space composition over a known length of time allows thecalculation of permeation.Since the headspace oxygen ismeasured as a percentage,the volume of the containersheadspace must be known to allow conversion into a quantitysuch as millilitres(ml)of oxygen.The use of this approach tomeasure permeation generally applies to empty package sys-tems only as oxygen uptake or outgassing of containedproducts could affect results.3.3.2 Leak DetectionIf the headspace contains more oxy-gen than expected or is increasing faster than expected,a leakcan be suspected.A wide variety of techniques can beemployed to verify that a leak is present and to identify itslocation.If necessary or of interest,a leak rate may becalculated with known headspace volume and measured oxy-gen concentration change over time.3.3.3 Effcacy of the MAP Packaging ProcessIf the head-space oxygen concentration is found to be higher than expectedsoon after packaging,the gas flushing process may not beworking as well as expected.Various techniques can evaluatewhether the MAP system is functioning properly.3.3.4 Storage StudiesAs the method is non-destructive,the headspace can be monitored over time on individualsamples to insure that results of storage studies such as shelflife testing are correctly interpreted.1This test method is under the jurisdiction ofASTM Committee F02 on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.40 onPackage Integrity Test Methods.Current edition approved Aug.1,2013.Published September 2013.Originallyapproved in 2008.Last previous edition approved in 2008 as F2714 08.DOI:10.1520/F2714-08R13.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Discussion4.1 Oxygen sensing based on fluorescence is well estab-lished.The typical indicators used are ruthenium complexesand porphyrins both of which are compatible with lightemitting diodes(LEDs).In one oxygen sensitive coating,tris(4,7 biphenyl 1,10 phenanthroline)ruthenium chloride is useddue to its stability,long lifetime,and strong absorption between400 nm and 500 nm in the blue region of the spectrum.Theabsorption peak is compatible with high brightness blue LEDsor blue semiconductor lasers.The emission peak is at 60