DIN-Fachbericht CEN TR 15314-2006 Durability of wood and wood-based products - Quantitative determination of quaternary ammonium compounds in wood English version CEN TR 15314 2006.pdf

1、Mrz 2006 Preisgruppe 8DIN Deutsches Institut fr Normung e.V. Jede Art der Vervielfltigung, auch auszugsweise, nurmit Genehmigung des DIN Deutsches Institut fr Normung e. V., Berlin, gestattet.ICS 79.040!,chi“9646970www.din.deDDIN-Fachbericht CEN/TR 15314Dauerhaftigkeit von Holz und Holzprodukten Qua

2、ntitative Bestimmung von quartren Ammoniumverbindungen in Holz Englische Fassung CEN/TR 15314:2006Durability of wood and wood-based products Quantitative determination of quaternary ammonium compounds in wood English version CEN/TR 15314:2006Durabilit du bois et des matriaux drivs du bois Dterminati

3、on quantitative des composs ammonium quaternaire dans le bois Version anglaise CEN/TR 15314:2006Alleinverkauf durch Beuth Verlag GmbH, 10772 Berlin www.beuth.deGesamtumfang 15 SeitenB55EB1B3E14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03DIN-Fachbericht CEN/TR 15314:2006-03 2 Nationales

4、Vorwort Dieses Dokument wurde vom Technischen Komitee CEN/TC 38 Dauerhaftigkeit von Holz und Holzprodukten erarbeitet. Fr die Deutsche Mitarbeit ist der Arbeitsausschuss NMP 412 Prfung von Holzschutzmitteln zustndig. B55EB1B3E14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03TECHNICAL REPOR

5、T RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN/TR 15314 January 2006 ICS 79.080 English version Durability of wood and wood-based products Quantitative determination of quaternary ammonium compounds in wood Durabilit du bois et des matriaux drivs du bois - Dtermination quantitative des composs ammonium

6、 quaternaire dans le bois Dauerhaftigkeit von Holz und Holzprodukten Quantitative Bestimmung von quartren Ammoniumverbindungen in Holz This Technical Report was approved by CEN on 14 December 2005. It has been drawn up by the Technical Committee CEN/TC 38. CEN members are the national standards bodi

7、es of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR

8、 STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TR 15314:2006: EB55EB1B3E14C22109E918E8EA43

9、EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 2 Contents Page Foreword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Safety precautions.5 4 Principle5 5 Reagents.6 6 Apparatus .7 7 Preparation of the test sample .7 8 Procedure .7 9 Calculation and expression of results.8 10

10、Quality assurance9 11 Precision.9 12 Test report 9 Annex A (informative) Ring test results . 10 Annex B (informative) Environmental, health and safety precautions within chemical/biological laboratory 11 Annex C (informative) Determination of the molar mass of the QAC . 12 Bibliography. 13 B55EB1B3E

11、14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 3 Foreword This Technical Report (CEN/TR 15314:2006) has been prepared by Technical Committee CEN/TC 38 Durability of wood and wood-based products, the secretariat of which is held by AFNOR. B55EB1B3E14C22109E918E8EA43E

12、DB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 4 Introduction At present, no standardised method for the analysis of quaternary ammonium compounds (QAC) in wood is recognised in Europe. Only a few national standards are available world wide, e.g. ASTM D5584-94, AWPA A 16-93 or AWPA A

13、18-04. This CEN Technical Report has been issued in order to facilitate the analysis of QAC-treated wood. B55EB1B3E14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 5 1 Scope This CEN Technical Report specifies a laboratory method of determining the content of quaterna

14、ry ammonium compounds in commercially QAC-treated wood. The method described has a measurement range up to QAC contents of 1 500 mg/kg of dry matter. NOTE 1 This method may need some modifications with some wood species such as hardwoods. NOTE 2 It is applicable to QAC with a molar mass ranging betw

15、een 200 g/mol and 500 g/mol. NOTE 3 The method has a quantification limit corresponding to 250 mg of QAC per kilogram of wood expressed as dry matter. 2 Normative references The following referenced documents are indispensable for the application of this CEN Technical Report. For dated references, o

16、nly the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 322, Wood-based panel Determination of moisture content EN ISO 1042, Laboratory glassware One-mark volumetric flasks (ISO 1042:1998) EN ISO 2871-2:1994, Surface

17、 active agents Detergents Determination of cationic-active matter content Part 2: Cationic active matter of low molecular mass (between 200 and 500) (ISO 2871-2:1990) EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) EN ISO 4788, Laboratory glassware Gra

18、duated measuring cylinders (ISO 4788:2005) ISO 385-1, Laboratory glassware Burettes Part 1: General requirements ISO 648, Laboratory glassware One-mark pipettes ISO 835-2, Laboratory glassware Graduated pipettes Part 2: Pipettes for which no waiting time is specified 3 Safety precautions Persons usi

19、ng this method shall be familiar with normal analytical laboratory procedures and practice. This method does not purport to address all the safety problems, if any, associated with its use. It is the responsibility of the user to establish health and safety practices and to ensure compliance with an

20、y. European or national regulatory conditions (also see Annex B for environmental, health and safety precautions) shall be taken into account. 4 Principle The quaternary ammonium compound is extracted from the wood material using a mixture of methanol and hydrochloric acid in an ultrasonic bath. B55

21、EB1B3E14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 6 The quaternary ammonium compound (cationic substance) is quantified by titration with an anionic surface active agent standard solution (sodium dodecyl sulfate) containing a mixture of a cationic and an anionic

22、dye. The titration is performed in a 2-phase system consisting of water and trichloromethane according to EN ISO 2871-2. Cationic substances and the anionic dye (disulphine blue VN 150) constitute a salt which is soluble in trichloromethane and results in a blue colour. The anionic dye in the salt i

23、s replaced gradually by the anionic surface active agent during the titration process leading to a discoloration of the organic phase at equivalence point. At the same time the disulphine blue moves into the water. NOTE 1 Cationic surface active agents as well as other disulphine blue active substan

24、ces will also react with the titrant and be determined as QAC. NOTE 2 In order to determine the mass of QAC its molar mass is required. 5 Reagents During the analysis, unless, otherwise specified, use only reagents of recognised analytical grade that have been checked in advance as to not interfere

25、with the analytical results, and water complying with grade 3 as defined in EN ISO 3696. 5.1 Trichloromethane (CAS 67-66-3) (CHCl3). 5.2 Methanol (CH3OH). NOTE Other solvents may be used instead of methanol as some extraction difficulties can occur with some wood species (e.g. hardwoods). It is reco

26、mmended to cross check the extraction efficiency of any other solvent or solvent mixture with that of methanol / hydrochloric acid used. 5.3 Dimidiumbromide (CAS 518-67-2) (C20H18BrN3). 5.4 Disulphine blue VN 150 (CAS 129-17-9) (C27H31N2S2O6Na). 5.5 Sodium dodecyl sulfate for analysis of surface act

27、ive agents (CAS 151-21-3) (C12H25SO4Na). 5.6 Hydrochloric acid solution, c(HCl) = 1 mol/l. Dilute 9 ml of concentrated hydrochloric acid ( 20 = 1,18 g/ml) to 100 ml with water. NOTE Test ampoules containing a definite amount may be used for the preparation of the hydrochloric acid solution instead o

28、f concentrated hydrochloric acid. 5.7 Ethanol, (C2H5OH) aqueous solution volume fraction 10 %. Add 30 ml of ethanol to 270 ml of water and mix well. 5.8 Sulfuric acid, solution c(H2SO4)= 2,5 mol/l. Cautiously add, with stirring and cooling, 14 ml of concentrated sulfuric acid ( 20 = 1,84 g/ml) to ab

29、out 80 ml of water and dilute to 100 ml with water. NOTE Test ampoules containing a definite amount may be used for the preparation of the sulfuric acid solution instead of concentrated sulfuric acid. B55EB1B3E14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 7 6 Appar

30、atus Ordinary laboratory apparatus and the following. NOTE Glassware should be thoroughly cleaned prior to use by means of ethanol. 6.1 Analytical balance, accurate to 0,1 mg. 6.2 Ultra-sonic bath. 6.3 Volumetric glassware, of class A quality in accordance with ISO 385-1 for the burettes, ISO 835-2

31、and ISO 648 for the pipettes, EN ISO 4788 for the measuring cylinders and EN ISO 1042 for the volumetric flasks. The burette shall be 10 ml graduated in 0,02 ml. 6.4 Conical flasks with glass stopper, 100 ml capacity. 6.5 Polytetrafluoroethylene (PTFE) filter, porosity 0,45 m (e.g. combined with a s

32、yringe). 6.6 Variable dispenser (5ml to 30ml). 7 Preparation of the test sample Collect at least 20 g of the sample material taken according to e.g. EN 212. This sample material is preferably ground under mild conditions to a powder with a particle size of less than 0,5 mm diameter. Homogenise the g

33、round material to obtain a representative sample, and store it in a brown glass bottle with screw caps with a polytetrafluoroethylene (PTFE) insert. This is the test sample. 8 Procedure 8.1 General It is recommended to carry out at least two parallel analyses. If the results differ by more than 10 %

34、 an additional analysis shall be made. 8.2 Standard solutions 8.2.1 Sodium dodecyl sulfate solution Dissolve 1,442 g sodium dodecyl sulfate (5.5) in water into a 1 000 ml volumetric flask (6.3) resulting in a concentration of 0,005 mol/l. NOTE The purity of the sodium dodecyl sulfate may be determin

35、ed by the method given in 4.2.1 of EN ISO 2871-2:1994. 8.2.2 Indicator solution Weigh (500 5) mg dimidiumbromide (5.3) into a 100 ml beaker and dissolve it in 30 ml hot aqueous ethanol (5.7). Then weigh (250 5) mg disulphine blue VN 150 (5.4) into a 100 ml beaker and dissolve it in 30 ml hot aqueous

36、 ethanol (5.7). After cooling, transfer both solutions quantitatively into a 250 ml volumetric flask and make up to the mark with aqueous ethanol. Transfer 20 ml of this solution into a 500 ml volumetric flask which already contains approximately 200 ml water. Finally add 20 ml of 2,5 mol/l sulfuric

37、 acid (5.8) and make up to the mark with water. NOTE The indicator solution should be stored in the dark. B55EB1B3E14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 8 8.3 Determination of the QAC content in treated timber 8.3.1 Extraction From the prepared timber sampl

38、e (Clause 7), remove a small portion of this sample (0,5 0,05) g and determine its moisture content according to EN 322; record the value obtained. Depending on the expected QAC content, transfer 5 g to 10 g of the test sample (7) to a flask of known mass (m1) and reweigh the flask and contents (m2)

39、. Calculate the mass of the test sample (m3= m2 m1) and add, to the nearest 0,5 ml, 7,0 times m3 ml of methanol and, to the nearest 0,05 ml, 0,1 times m3ml of the hydrochloric acid (5.6). NOTE 1 A 100 ml flask is suitable for test samples of 10 g. Place the hydrochloric acidic suspension in an ultra

40、sonic bath (6.2) and agitate it for 1 h. Allow the warm suspension to cool at room temperature, weigh and add methanol to give a total extract mass of 7,50 times m3(total mass of flask and contents is m1+ 8,5 times m3), to the nearest 0,1 g; record the total mass as m4. Stopper the flask, swirl the

41、contents vigorously and store to clear over night (at least 12 h). Remove a part of the clear solution and filter by means of a 0,45 m PTFE-filter (6.5). Use 10 g to 30 g of the filtered solution for the quantitative determination of QAC depending on the expected concentration. NOTE 2 Since a comple

42、te extraction is essential for a successful analysis, treated timber with a known QAC content should be analysed in parallel. 8.3.2 Sample analysis Depending on the expected QAC concentration transfer up to 30 g of the methanolic extract into a tared conical flask (6.4) and weigh to determine the ma

43、ss of extract taken (m5). Add 20 ml water, swirl to mix and then add 15 ml trichloromethane (5.1) and 10 ml of indicator solution (8.2.2) by graduated cylinder. Carry out the titration using the 0,005 mol/l sodium dodecyl sulfate solution (8.2.1) drop wise. Shake intensively after each drop and wait

44、 until the layers have separated again. NOTE The aqueous layer is a light green colour near the equivalence point whereas the organic phase seems to be red-violet. When the equivalence point is reached the addition of further sodium dodecyl sulfate results in a red-violet colour of the organic phase

45、. 9 Calculation and expression of results The QAC content, w, in moles per kilogram of the test sample is calculated using the following equation (1): w = 5324)(mmmmcV(1) where V is the volume, in millilitres, of the sodium dodecyl sulfate solution (8.2.1) used for titration; C is the concentration

46、of the sodium dodecyl sulfate solution (8.2.1) in moles per litre; m4is the total mass of flask and contents in grams; m2is the mass of flask and test sample in grams; B55EB1B3E14C22109E918E8EA43EDB30F09CC9B7EF8DD9NormCD - Stand 2007-03CEN/TR 15314:2006 (E) 9 m3is the amount of test sample in grams;

47、 m5is the amount of extract used for the titration, in grams. The QAC content, wt, in grams per kilogram of oven dry treated timber is calculated using the following equation (2): wt= 100)100(cmMw +(2) where w is the QAC content of the test sample in moles per kilogram (from equation (1); M is the m

48、olar mass of the quaternary ammonium compound in grams per mole (see Annex C); mcis the percentage moisture content of the test sample (8.3.1). The QAC content of the test sample is given in grams per kilogram of dry matter as the mean of independent determinations together with its measurement unce

49、rtainty. 10 Quality assurance When establishing this method in the laboratory it is recommended that a reference material (RM) with a known QAC content is used for verification. 11 Precision This method was validated in a laboratory inter-comparison with seven participating laboratories for three test samples at different levels of QAC content (see Annex A). 12 Test report The test report shall contain the following information: a) reference to this CEN Technical Report, i.e. CEN/TR 15314; b) date of samp