1、PUBLISHED DOCUMENT PD CEN/TR 15314:2006 Durability of wood and wood-based products Quantitative determination of quaternary ammonium compounds in wood ICS 79.080 PD CEN/TR 15314:2006 This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 July 2
2、006 BSI 2006 ISBN 0 580 49007 6 National foreword This Published Document is the official English language version of CEN/TR 15314:2006. The UK participation in its preparation was entrusted by Technical Committee B/515, Wood preservation, to Subcommittee B/515/1, Preservative preconditioning and bi
3、ological testing, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI
4、Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for it
5、s correct application. Compliance with a Published Document does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests
6、 informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the CEN/TR title page, pages 2 to 13 and a back cover. The BSI copyright notice displayed in this document indicates when t
7、he document was last issued. Amendments issued since publication Amd. No. Date CommentsTECHNICALREPORT RAPPORTTECHNIQUE TECHNISCHERBERICHT CEN/TR15314 January2006 ICS79.080 EnglishVersion DurabilityofwoodandwoodbasedproductsQuantitative determinationofquaternaryammoniumcompoundsinwood Durabilitduboi
8、setdesmatriauxdrivsdubois Dterminationquantitativedescompossammonium quaternairedanslebois DauerhaftigkeitvonHolzundHolzproduktenQuantitative BestimmungvonquartrenAmmoniumverbindungenin Holz ThisTechnicalReportwasapprovedbyCENon14December2005.IthasbeendrawnupbytheTechnicalCommitteeCEN/TC38. CENmembe
9、rsarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Romania, Slovakia,Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMIT
10、TEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2006CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.CEN/TR15314:2006:E2 Contents Page Foreword 3 Introduction4 1 Scope .5 2 No
11、rmative references .5 3 Safety precautions5 4 Principle.5 5 Reagents6 6 Apparatus 7 7 Preparation of the test sample.7 8 Procedure 7 9 Calculation and expression of results.8 10 Quality assurance .9 11 Precision9 12 Test report .9 Annex A (informative) Ring test results10 Annex B (informative) Envir
12、onmental, health and safety precautions within chemical/biological laboratory 11 Annex C (informative) Determination of the molar mass of the QAC.12 Bibliography.13 CEN/TR 15314:20063 Foreword This Technical Report (CEN/TR 15314:2006) has been prepared by Technical Committee CEN/TC 38 “Durability of
13、 wood and wood-based products”, the secretariat of which is held by AFNOR. CEN/TR 15314:20064 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 D55
14、84-94, AWPA A 16-93 or AWPA A 18-04. This CEN Technical Report has been issued in order to facilitate the analysis of QAC-treated wood. CEN/TR 15314:20065 1 Scope This CEN Technical Report specifies a laboratory method of determining the content of quaternary ammonium compounds in commercially QAC-t
15、reated 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 between 200 g/mol and 500 g/mol. NOTE 3 The met
16、hod 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, only the edition cited applies. For undated
17、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 active agents Detergents Determination of
18、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 Graduated measuring cylinders (ISO 4788:2005)
19、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 using this method shall be familiar with norma
20、l 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 any. European or national regulatory conditio
21、ns (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. CEN/TR 15314:20066 The quaternary ammonium com
22、pound (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 dye. The titration is performed in a 2-phase system consisting of water and trichloromethane according to EN ISO 287
23、1-2. 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 is replaced gradually by the anionic surface active agent during the titration process leading to a discoloration of
24、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 substances will also react with the titrant and be determined as QAC. NOTE 2 In order to determine the mass of QAC its mola
25、r 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 with the analytical results, and water complying with grade 3 as defined in EN ISO 3696. 5.1 Trichloromethane (CAS 6
26、7-66-3) (CHCl 3 ). 5.2 Methanol (CH 3 OH). NOTE Other solvents may be used instead of methanol as some extraction difficulties can occur with some wood species (e.g. hardwoods). It is recommended to cross check the extraction efficiency of any other solvent or solvent mixture with that of methanol /
27、 hydrochloric acid used. 5.3 Dimidiumbromide (CAS 518-67-2) (C 20 H 18 BrN 3 ). 5.4 Disulphine blue VN 150 (CAS 129-17-9) (C 27 H 31 N 2 S 2 O 6 Na). 5.5 Sodium dodecyl sulfate for analysis of surface active agents (CAS 151-21-3) (C 12 H 25 SO 4 Na). 5.6 Hydrochloric acid solution, c(HCl) = 1 mol/l.
28、 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 of concentrated hydrochloric acid. 5.7 Ethanol, (C 2 H 5 OH) aqueous solution volume fracti
29、on 10 %. Add 30 ml of ethanol to 270 ml of water and mix well. 5.8 Sulfuric acid, solution c(H 2 SO 4 )= 2,5 mol/l. Cautiously add, with stirring and cooling, 14 ml of concentrated sulfuric acid ( 20 = 1,84 g/ml) to about 80 ml of water and dilute to 100 ml with water. NOTE Test ampoules containing
30、a definite amount may be used for the preparation of the sulfuric acid solution instead of concentrated sulfuric acid. CEN/TR 15314:20067 6 Apparatus Ordinary laboratory apparatus and the following. NOTE Glassware should be thoroughly cleaned prior to use by means of ethanol. 6.1 Analytical balance,
31、 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 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,
32、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 syringe). 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
33、. 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 ground material to obtain a representative sample, and store it in a brown glass bottle with screw caps with a polytetrafluoroethylene (PTFE) insert. This i
34、s 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 % 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
35、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 determined 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 i
36、t 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 ethanol (5.7). After cooling, transfer both solutions quantitatively into a 250 ml volumetric flask and make up to the mark with aqueous ethanol. Transfe
37、r 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 acid (5.8) and make up to the mark with water. CEN/TR 15314:20068 NOTE The indicator solution should be stored in the dark. 8.3 Determination of the QAC
38、content in treated timber 8.3.1 Extraction From the prepared timber sample (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
39、(7) to a flask of known mass (m 1 ) and reweigh the flask and contents (m 2 ). Calculate the mass of the test sample (m 3= m 2 m 1 ) and add, to the nearest 0,5 ml, 7,0 times m 3 ml of methanol and, to the nearest 0,05 ml, 0,1 times m 3ml of the hydrochloric acid (5.6). NOTE 1 A 100 ml flask is suit
40、able for test samples of 10 g. Place the hydrochloric acidic suspension in an ultrasonic 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 m 3(total mass of flask and contents is m 1+ 8,5 times
41、m 3 ), to the nearest 0,1 g; record the total mass as m 4 . Stopper the flask, swirl the 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 quantit
42、ative determination of QAC depending on the expected concentration. NOTE 2 Since a complete 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
43、 of the methanolic extract into a tared conical flask (6.4) and weigh to determine the mass of extract taken (m 5 ). 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 so
44、dium dodecyl sulfate solution (8.2.1) drop wise. Shake intensively after each drop and wait 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 add
45、ition of further sodium dodecyl sulfate results in a red-violet colour of the organic phase. 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 = 5 3 2 4 ) ( m m m m c V ( 1 ) where V is the volume, i
46、n millilitres, of the sodium dodecyl sulfate solution (8.2.1) used for titration; C is the concentration of the sodium dodecyl sulfate solution (8.2.1) in moles per litre; m 4is the total mass of flask and contents in grams; CEN/TR 15314:20069 m 2is the mass of flask and test sample in grams; m 3is
47、the amount of test sample in grams; m 5is the amount of extract used for the titration, in grams. The QAC content, w t , in grams per kilogram of oven dry treated timber is calculated using the following equation (2): w t= 100 ) 100 ( c m M w + ( 2 ) where w is the QAC content of the test sample in
48、moles per kilogram (from equation (1); M is the molar mass of the quaternary ammonium compound in grams per mole (see Annex C); m cis 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 uncertainty. 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-c
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