1、BRITISH STANDARD CONFIRMED APRIL 1989 BS2690-116: 1983 Methods of testing Water used in industry Part116: Morpholine: spectrophotometric method IMPORTANT NOTE. It is essential that this Part be read in conjunction with the information in Part100 of this standard, “Foreword, scope and general require
2、ments”, which is published separately. UDC628.1:663.63.01:543.3:543.42.062:547.867.4BS2690-116:1983 This British Standard, having been prepared under the directionof the Environment andPollution Standards Committee, was published underthe authority of the BoardofBSI and comes into effect on 31 May 1
3、983 BSI08-1999 The following BSI references relate to the work on this standard: Committee reference EPC/37 Special announcement in BSINews March 1983 ISBN 0 580 11972 6 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsi
4、ble for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 and 2, an inside back cover and a back cover. This standard has been
5、updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS2690-116:1983 BSI 08-1999 i Contents Page 0 Introduction 1 1 Scope 1 2 Range 1 3 Princi
6、ple 1 4 Interferences 1 5 Reagents 1 6 Treatment of apparatus 1 7 Sampling 2 8 Preparation of calibration graph 2 9 Procedure 2 10 Calculation 2 Publications referred to Inside back coverii blankBS2690-116:1983 BSI 08-1999 1 0 Introduction BS2690-115, BS2690-116 and BS2690-117 together supersede BS2
7、690-8:1969. This Part is a revision of clause3. 1 Scope The method described is for the determination of morpholine in industrial waters by a spectrophotometric method. 2 Range From24g to1004g of morpholine in a test portion not exceeding25mL. 3 Principle Morpholine and carbon disulphide react, at a
8、 pH of about9.2, to form a thiocarbamate which will combine with an excess of copper to form an amber-coloured complex, which is extracted into chloroform and determined colorimetrically. 4 Interferences The basic reaction of the method is common to many amines, and, whilst cyclohexylamine causes ma
9、rked positive interference, it is normally not present with morpholine. Under the conditions described in the method, the presence of2.54g of nickel (Ni 2+ ),104g of octadecylamine,254g of hydrazine, ferric (Fe 3+ ) and ferrous (Fe 2+ ) iron,1004g of copper (Cu 2+ ) and10004g of ammonia individually
10、 causes no significant interference. 5 Reagents 5.1 EDTA solution. Dissolve0.125g of disodium dihydrogen ethylene-diamine-NNN“N”-tetra-acetate dihydrate (EDTA) in about50mL of water, add2.5mL of a10g/L solution of sulphuric acid 1) , and dilute with water to the mark in a250mL one-mark volumetric fl
11、ask to give a0.5g/L solution. 5.2 Copper (II) sulphate solution. Dissolve0.5g of copper (II) sulphate pentahydrate (CuSO 4 .5H 2 O) in about50mL of water, add2.5mL of a10g/L solution of sulphuric acid 1) , and dilute with water to the mark in a250mL one-mark volumetric flask to give a2g/L solution.
12、5.3 Dilute hydrochloric acid solution. Dilute500mL of concentrated hydrochloric acid ( 20 =1.18g/mL) with500mL of water. 5.4 Carbon disulphide solution WARNING. Carbon disulphide is extremely flammable and very toxic by inhalation. Avoid breathing its vapour. Carry out this preparation in a fume cup
13、board away from sources of heat and naked flames. To about400mL of acetone in a500mL one-mark volumetric flask add, from a safety pipette,5.0mL of carbon disulphide. Dilute to the mark with acetone and mix. Store out of direct sunlight. Prepare this solution fresh before each batch of analyses. 5.5
14、Chloroform WARNING. Chloroform is harmful by inhalation. Avoid breathing its vapour and contact with eyes. It is also a suspected carcinogen. 5.6 Borax buffer solution. Dissolve100g of sodium tetraborate decahydrate (Na 4 B 2 O 7 .10H 2 O) in500mL of warm water and cool. The pH value is9.2. 5.7 Morp
15、holine standard solutions 5.7.1 Morpholine stock solution. Using a safety pipette introduce2.00mL of morpholine into about900mL of water in a1000mL one-mark volumetric flask, keeping the tip of the pipette just below the surface of the water. Dilute to the mark with water and mix. 5.7.2 Morpholine w
16、orking solution. Pipette10.00mL of the morpholine stock solution(5.7.1) into about900mL of water in a1000mL one-mark volumetric flask, keeping the tip of the pipette just below the surface of the water. Dilute to the mark with water and mix.(1mLN 204g of morpholine). 6 Treatment of apparatus Clean a
17、 series of100mL separating funnels with the dilute hydrochloric acid solution(5.3), and rinse with water. Seven funnels are required to prepare the calibration graph (seeclause8) and two for the procedure (seeclause9). 1) 0.1N solution.BS2690-116:1983 2 BSI 08-1999 7 Sampling If the temperature of t
18、he water being sampled is above25 C, the sampling line shall contain a stainless steel cooling coil capable of reducing the temperature of the sample to25 C. Clean a ground-glass stoppered bottle of known capacity (about250mL) with the dilute hydrochloric acid solution(5.3), rinse well with water an
19、d dry. Before sampling introduce10.0mL of the EDTA solution(5.1) into the bottle. Fill the bottle with the cooled sample, stopper it and mix the contents. 8 Preparation of calibration graph Add24,23.5,23,22,21,20 and19mL of water to a series of100mL separating funnels. In the same order add0,0.5,1.0
20、,2.0,3.0,4.0 and5.0mL of the morpholine working solution(5.7.2) and mix. These solutions will, respectively, correspond to0,10,20,40,60,80 and1004g of morpholine in a separating funnel. Treat the contents of each funnel as follows. Add1.00mL of the EDTA solution(5.1). Mix and then add from a burette
21、25mL of the carbon disulphide solution(5.4). Swirl the contents for a few seconds. Add, within2min,2.5mL of the borax buffer solution(5.6) and again swirl the contents of the funnel. After2min, add1.00mL of the copper(II) sulphate solution(5.2) followed by20.0mL of the chloroform(5.5) from a burette
22、. Within1min, add0.5mL of the dilute hydrochloric acid solution(5.3) and shake the separating funnel for1min. Allow the funnel to stand until the phases have separated. Dry the stem of the funnel with a strip of filter paper and then filter the chloroform layer through a fast, medium grade filter pa
23、per 2)into a dry40mm cell. Measure the absorbance of the chloroform solution at a known temperature between20 C and25 C in a spectrophotometer at the wavelength corresponding to maximum absorption (approximately435nm, but the exact wavelength shall be checked for each spectrophotometer), using40mm c
24、ells. Use chloroform in the compensating cell. Deduct the reading for the blank from those for the standard solutions and plot a calibration graph of absorbance against the number of micrograms of morpholine. The absorbance given by1004g of morpholine in the total volume of test solution is approxim
25、ately0.75. 9 Procedure Pipette a suitable volume of the treated sample (containing less than1004g of morpholine), collected as described in clause7, into a100mL separating funnel. If necessary adjust the pH to pH4.5 to5.5 by the addition of the dilute hydrochloric acid solution(5.3), and dilute to25
26、mL. Into a second funnel, introduce24.0mL of water and1.0mL of the EDTA solution(5.1) to act as a blank. Treat the contents of each funnel as follows. Add from a burette25.0mL of the carbon disulphide solution(5.4) and swirl the contents of the funnel for a few seconds. Add, within2min,2.5mL of the
27、borax buffer solution(5.6) and again swirl the contents of the funnel. After2min, add1.00mL of the copper (II) sulphate solution(5.2) followed by20.0mL of the chloroform(5.5) from a burette. Within1min, add0.5mL of the dilute hydrochloric acid solution(5.3) and shake the separating funnel for1min. A
28、llow the funnel to stand until the phases have separated. Dry the stem of the funnel with a strip of filter paper and then filter the chloroform layer through a fast, medium grade filter paper 2)into a dry40mm cell. Measure the absorbance of the chloroform solution at the wavelength used for the cal
29、ibration graph and at a temperature within1 C of that at which the calibration graph was prepared in the spectrophotometer. Use chloroform in the compensating cell. 10 Calculation Deduct the reading obtained for the blank from that for the sample and read off the morpholine content in micrograms fro
30、m the calibration graph. The concentration, in milligrams per litre, of morpholine is given by 2) Whatman No.41 paper is suitable. where m is the mass of morpholine from the calibration graph (in 4g); V is the volume of sample (in mL). m V -BS2690-116:1983 BSI 08-1999 Publications referred to BS2690
31、, Methods of testing water used in industry. BS2690-115, Cyclohexylamine: spectrophotometric method 3) . BS2690-117, Long-chain fatty amines: spectrophotometric method 3) . 3) Referred to in the introduction only.BS2690-116: 1983 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitutio
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