ASTM D4307-17 Standard Practice for Preparation of Liquid Blends for Use as Analytical Standards.pdf

1、Designation: D4307 17Standard Practice forPreparation of Liquid Blends for Use as AnalyticalStandards1This standard is issued under the fixed designation D4307; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis

2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers a laboratory procedure for thepreparation of small volumes of multicomponent liquid blendsfor use as analy

3、tical standards.1.2 This practice is applicable to components that arenormally liquids at ambient temperature and pressure, or solidsthat will form a solution when blended with liquids. Butanescan be included if precaution is used in blending them.1.3 This practice is limited to those components tha

4、t fulfillthe following conditions:1.3.1 They are completely soluble in the final blend.1.3.2 They are not reactive with other blend components orwith blend containers.1.3.3 The combined vapor pressure of the blended compo-nents is such that there is no selective evaporation of any of thecomponents.1

5、.3.3.1 The butane content of the blend is not to exceed10 %. (WarningExtremely flammable liquefied gas underpressure. Vapor reduces oxygen available for breathing.) Com-ponents with a vapor pressure higher than butanes are not to beblended.1.4 The values stated in SI units are to be regarded as thes

6、tandard.1.5 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.1.6 Thi

7、s international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade

8、(TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1364 Test Method for Water in Volatile Solvents (KarlFischer Reagent Titration Method)3. Summary of Practice3.1 The individual blend components are precisely weighedand combined in an inert, tight-sealing glass vial or similarcontainer. Whe

9、n volatility is a consideration, the componentsof lowest vapor pressure (least volatile) are added first and thehighest (most volatile) last. Mass (weight) percent compositionof the final blend is calculated from the mass and purities of thepure components. Volume percent composition can be calcu-la

10、ted using the density of each component.4. Significance and Use4.1 The laboratory preparation of liquid blends of knowncomposition is required to provide analytical standards for thecalibration of chromatographic and other types of analyticalinstrumentation.5. Apparatus5.1 Containers:5.1.1 Vial, gla

11、ss, threaded neck, approximately 22 mLcapacity, short style. Vials of other capacities may be substi-tuted as required. When blending light-sensitive components,use amber glass vials or wrap clear glass vials with black tape.5.1.2 Bottle Cap, molded plastic with TFE-fluorocarbon,polypropylene, or po

12、lyethylene conical liner.5.1.3 Bottle Cap, molded plastic with aluminum foil liner.Aluminum foil liners are preferred to other metal linersbecause they seal better.5.1.4 Mininert Valve, screw cap, 20 mm or appropriate sizeto match vial size used. These caps are especially valuable forpreparing blend

13、s that contain volatile components.NOTE 1The use of Mininert valves is recommended when compo-nents lighter than hexane are contained in the liquid blends.1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricants and is the direct responsibilit

14、y of Subcom-mittee D02.04.0A on Preparation of Standard Hydrocarbon Blends.Current edition approved May 1, 2017. Published May 2017. Originallyapproved in 1983. Last previous edition approved in 2015 as D4307 99 (2015).DOI: 10.1520/D4307-17.2For referenced ASTM standards, visit the ASTM website, www

15、.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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO

16、 Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued b

17、y the World Trade Organization Technical Barriers to Trade (TBT) Committee.15.2 Balance, capable of weighing to 0.1 mg.5.3 Pipet, dropping, medicine dropper.5.4 Spatula, semi-micro, scoop style.6. Reagents and Materials6.1 Blend Components, high-purity, as required dependingon the composition requir

18、ements of the proposed blend.6.1.1 To verify the purity of blend components, analyzeeach compound by the same technique for which the blend isintended or by another suitable technique. Check for otherimpurities such as water, if necessary. Water cannot be deter-mined with sufficient accuracy by most

19、 GC methods and mustbe measured by other procedures such as Test Method D1364,or equivalent, and the result used to normalize the chromato-graphic value. If any of the impurities found are othercomponents of the blend, determine their concentrations andmake appropriate corrections.7. Procedure7.1 Ex

20、amine the vial and cap to verify that a leak-freeclosure is obtained. The rim at the top of the vial should besmooth and flat and the cap should fit snugly.7.1.1 Glass vials are inert to most compounds and are theusual choice. Plastic containers shall never be used sincespecific compounds can prefer

21、entially diffuse through them.7.1.2 Plastic caps with aluminum foil liners provide a goodseal unless blend components react with the aluminum. Poly-ethylene or polypropylene-lined caps usually provide a goodclosure but are not to be used for aromatic hydrocarbons andsimilar compounds since these mat

22、erials will, with time,diffuse through the liner.7.2 Weigh the vial and cap to the nearest 0.1 mg. Removethe cap and add the first component to the vial, being carefulnot to allow the component to contact the rim of the vial, whichcould produce losses. Liquids may be added by either pipet ormedicine

23、 dropper while solids are usually added with a smallspatula. Place the cap on the vial and reweigh to the nearest0.1 mg, recording the mass. Repeat this procedure with eachadditional component, always being careful not to allow thecontents of the vial to contact the cap. After all componentshave bee

24、n added and the final weighing completed, thoroughlyshake the vial to mix the solution.7.2.1 When volatile components are being combined, thelowest vapor pressure (least volatile) compound is added firstand the highest (most volatile) last.NOTE 2Exercise care when adding additional components since

25、theresulting agitation can lead to excessive loss of headspace and acts toamplify the preferential removal of more volatile components from theblend. This condition is further amplified by the fact that each time the vialcap is removed, the equilibrium of the headspace will be altered. Sinceliquid f

26、ilms form spontaneously on the vial caps from super-saturatedheadspaces and from equilibrium processes of evaporation and conden-sation (especially if the vial is cooled), all of the blend components shouldbe added to the blend in as short a time as is reasonable.7.2.2 For blending very volatile com

27、ponents, it is advisableto reduce the volatility when the vial is uncapped by coolingthe vial to about 4 C between weighings. When this techniqueis utilized, the volatile component is added, and the vial isclosed and weighed. The vial and contents then are chilledthoroughly before the vial is opened

28、 to allow addition of thenext component. The next component is added quickly, the vialclosed, and the vial and contents brought to ambient tempera-ture before the mass is obtained. Exercise care to ensure thatmoisture condensed on the exterior of the vial is removedbefore weighing. After weighing, t

29、he vial and contents arere-chilled before the vial is opened to permit addition of thenext component.7.3 To prepare a blend containing components at lowconcentration, for example, mg/kg, where the weighed quan-tities would be too small for sufficient accuracy, it is necessaryto make an initial blend

30、 of those components at higherconcentrations. Successive dilutions are then made until thefinal desired concentration is reached. For example, if a blendis desired that contains 56 mg kg (mass-ppm) n-heptane incyclohexane, weigh together 2 mL of n-heptane and 20 mL ofcyclohexane. Make certain that b

31、etween all weighings theunmixed liquid does not contact the container cap, which couldcause preferential losses. After both components have beenadded, thoroughly mix this blend by shaking. Make threesuccessive dilutions, with careful weighings, of one part(2 mL) of blend with ten parts (20 mL) of cy

32、clohexane. Shakethoroughly between each dilution. Each blend should have afinished volume of 22 mL so that quantities are large enough toweigh accurately. The mass-ppm of n-heptane in the final blendis calculated from the recorded weights.8. Preblending Calculations8.1 In order to make blends of com

33、ponents at specific levels,it is necessary to calculate beforehand the mass of eachcomponent required to achieve these levels. Calculate thesemasses as follows:WN5AT100(1)where:WN= mass of component N to be added, g,A = desired mass percentage in the final blend, andT = desired mass of the total fin

34、al blend, g.9. Calculations9.1 Calculate the mass percent concentration of each com-ponent as follows:N, mass% 5WN3100(WN1Wo1WP.!(2)where:WN,WO,WP= mass of components N, O, P, etc, g.9.1.1 When an added component is less than 100 % pure(see 6.1.1), corrections shall be made to the mass of thatcompou

35、nd, as well as to other components included in theblend. For example, if the mass of component N added to theblend is 3.0 g but previous analysis indicated it to be 95 %component N, 3 % component O, and 2 % component P, thenthe actual mass of component N in the blend would be 2.85 g,and 0.09 g and 0

36、.06 g would need to be added to the masses ofcomponents O and P, respectively.D4307 1729.1.1.1 When a standard being prepared contains one ormore components being used as an internal standard, Eq 2 shallnot include the mass of the internal standard component(s) inthe denominator summation when calcu

37、lating the mass percentof the other components in the blend. The mass of the internalstandard component(s) is only included in the denominatorsummation in Eq 2 when calculating the mass percent of theinternal standard component(s) in the blend.9.1.1.2 Example CalculationsThe following mixture waspre

38、pared (for simplicity, purities were not taken into accountfor this example).Component Mass (g)Methyl tert-Butyl Ether 15.02Ethanol 10.05Methanol 5.021-Propanol 3.03Gasoline 66.881,2-Dimethoxyethane 5.25Calculations:Sample: 15.02g+10.05g+5.02g+3.03g+66.88g=100.00 gMTBE Concentration: 15.02 g/100.00

39、g = 15.02 % by massEthanol Concentration: 10.05 g/100.00 g = 10.05 % by massMethanol Concentration: 5.02 g/100.00g=5.02%bymass1-Propanol Concentration: 3.03 g/100.00g=3.03%bymassInternal standard calculation:1,2-Dimethoxyethane Concentration: 5.25 g/105.25g=4.99%bymass9.2 Calculate the volume percen

40、t concentration of eachcomponent as follows:N, volume% 5WN/DN! 3100(WN/DN!1WO/DO!1WP/DP! .#(3)where:WN,WO,WP= mass of components N, O, P, etc, g, andDN,DO,DP= density of components N, O, P, etc., alldetermined at the same temperature.9.2.1 The final volume of the solution is not necessarily thesame

41、as the sum of the volumes of the components due topossible expansion or contraction on mixing.9.2.1.1 When a standard being prepared contains one ormore components being used as an internal standard, Eq 3 shallnot include the mass/density ratio of the internal standardcomponent(s) in the denominator

42、 summation when calculatingthe volume percent of the other components in the blend. Themass/density ratio of the internal standard component(s) is onlyincluded in the denominator summation of Eq 3 when calcu-lating the volume percent of the internal standard component(s)in the blend.10. Keywords10.1

43、 analytical standards; liquid blendsSUMMARY OF CHANGESSubcommittee D02.04 has identified the location of selected changes to this standard since the last issue(D4307 99 (2015) that may impact the use of this standard. (Approved May 1, 2017.)(1) Revised several subsections of Section 9.ASTM Internati

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