1、BRITISH STANDARD CONFIRMED APRIL1989 BS 2690-115: 1983 Methods of testing Water used in industry Part 115: Cyclohexylamine: 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 r
2、equirements”, which is published separately. UDC 628.1:663.63.01:543.3:543.42.062:547.592.15BS2690-115:1983 This British Standard, having been prepared under the directionof the Environment andPollution Standards Committee, was published underthe authority of the Board of BSI and comes intoeffecton
3、31 May1983 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference EPC/37 Special announcement in BSI News March1983 ISBN 0 580 11971 8 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are
4、responsible 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, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has b
5、een 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 CommentsBS2690-115:1983 BSI 08-1999 i Contents Page 0 Introduction 1 1 Scope 1 2 Range 1 3 Pr
6、inciple 1 4 Interferences 1 5 Sample collection 1 6 Reagents 1 7 Preparation of calibration graph 1 8 Procedure 2 9 Calculation 2 Appendix A Interference by ammonia 3 Publications referred to Inside back coverii blankBS2690-115:1983 BSI 08-1999 1 0 Introduction BS2690-115, BS2690-116 and BS2690-117
7、together supersede BS 2690-8:1969. This Part is a revision of clause2. 1 Scope The method described is for the determination of cyclohexylamine in industrial waters by a spectrophotometric method. 2 Range Up to2504g of cyclohexylamine in a test portion not exceeding50mL. 3 Principle Cyclohexyla mine
8、 reacts with sodium1,2-naphthoquinone-4-sulphonate to give a yellow compound which is extracted into chloroform and determined colorimetrically. NOTEThe method is susceptible to a number of experimental parameters. These include the temperature during, and the time allowed for, the reaction and the
9、intensity of daylight while the solutions are being treated prior to setting aside in the dark. Great care should be taken to ensure that, as far as possible, standards and blanks are exposed to the same influences as samples. 4 Interferences Significant interference by ammonia may result when some
10、batches of naphthoquinone-sulphonate reagent are used. In such circumstances ammonia reacts similarly to cyclohexylamine and its effect is approximately proportional to its concentration. A preliminary check, as described in Appendix A, shallbe conducted on each fresh batch of napthoquinone-sulphona
11、te reagent to determine the effect of ammonia. Under the conditions described in the method, the presence of504g of octadecylamine, hydrazine, ferric (Fe 3+ ) and ferrous (Fe 2+ ) iron, zinc (Zn 2+ ), nickel (Ni 2+ ), copper (Cu 2+ ), aluminium (Al 3+ ), chromium (Cr 3+ ), potassium (K + ), calcium
12、(Ca 2+ ) and magnesium (Mg 2+ ) and5004g of chloride (Cl ), sulphate (SO 4 2 ) and phosphate (PO 4 3 ) individually causes no significant interference. 5 Sample collection If the temperature of the water being sampled is above40 C, the sampling line shall contain a stainless steel cooling coil capab
13、le of reducing the temperature of the sample to below40 C. Collect the sample in a glass bottle, stopper, and, before analysis, cool the sample to within5 C of room temperature. 6 Reagents 6.1 Ammonia-free water. A satisfactory ammonia-free water can usually be obtained by shaking5L of water with10g
14、 of a strong cation exchange resin in the hydrogen form, or by passing water through a column of such resin. It may also be prepared by distilling tap water in an all-glass apparatus after adding1mL of0.5g/L sulphuric acid solution. 6.2 Naphthoquinone-sulphonate solution. Dissolve0.175g of sodium1,2
15、-naphthoquinone-4-sulphonate in water and dilute with water to the mark in a100mL one-mark volumetric flask. Prepare freshly each day, and store in the dark when not in use. A new calibration graph shall be constructed for each batch of reagent. 6.3 Phosphate buffer solution. Add35.0g of anhydrous d
16、isodium hydrogen orthophosphate (Na 2 HPO 4 ) to about400mL of water, and stir until all the solid is dissolved. Add30.0mL of40g/L sodium hydroxide solution. Transfer to a500mL one-mark volumetric flask and dilute to the mark with water. Stored in a polyethylene bottle, this solution is stable for a
17、t least3weeks. 6.4 Chloroform WARNING. Chloroform is harmful by inhalation. Avoid breathing its vapour and contact with eyes. It is also a suspected carcinogen. 6.5 Cyclohexylamine standard solutions 6.5.1 Cyclohexylamine stock solution. Using a safety pipette introduce5.00mL of cyclohexylamine into
18、 a1000mL one-mark volumetric flask and dilute to the mark with water. Store in a stoppered glass bottle for not longer than3weeks. 6.5.2 Cyclohexylamine working solution. Pipette5.00mL of the cyclohexylamine stock solution(6.5.1) into a1000mL one-mark volumetric flask and dilute to the mark with wat
19、er(1mL=21.74g of cyclohexylamine). Prepare this solution immediately before use. 7 Preparation of calibration graph Add0,1.0,2.5,5.0,7.5,10.0 and12.5mL of the cyclohexylamine working solution(6.5.2) to a series of100mL conical flasks. This will correspond to0,21.7,54.3,108.5,162.8,217.0 and271.34g o
20、f cyclohexylamine in a100mL flask. In each case make up to a total volume of50.0mL with the ammonia-free water(6.1). Treat the contents of each flask as follows.BS2690-115:1983 2 BSI 08-1999 Add1.00mL of the phosphate buffer solution(6.3) followed immediately by10.0mL of the naphthoquinone-sulphonat
21、e solution(6.2). Allow the mixture to stand for2h in the dark, and then transfer quantitatively to a250mL separating funnel, rinsing the flask with5mL of the ammonia-free water(6.1). Add20.0mL of the chloroform(6.4) to the separating funnel, swirl the contents of the funnel gently for a few seconds,
22、 cautiously releasing the pressure generated, and then shake the funnel vigorously for1min. Set the funnel aside in the dark (or otherwise shield from light) to allow phase separation and, when complete, rinse the bore of the separating funnel stopcock by running3mL to5mL of the chloroform extract t
23、o waste. Then pass a further2mL to3mL of the chloroform extract to waste through a fast, medium grade filter paper 1)held in a small glass filter funnel, and finally a further portion of the extract through the filter into a dry10mm spectrophotometer cell. Measure the absorbance of the solution at a
24、 known temperature between20 C and25 C in a spectrophotometer at the wavelength corresponding to maximum absorption (approximately449nm, but the exact wavelength shall be checked for each spectrophotometer), using10mm cells. Use chloroform in the compensating cell. Deduct the reading for the blank f
25、rom those for the standard solutions and plot a calibration graph of absorbance against the number of micrograms of cyclohexylamine. The absorbance given by2504g of cyclohexylamine in the total volume of test solution is approximately0.5. NOTEThe graph should be linear to at least2504g. 8 Procedure
26、Measure a suitable volume of the sample (containing less than2504g of cyclohexylamine) into a100mL conical flask and, if necessary, dilute to50mL with the ammonia-free water(6.1). Add50mL of the ammonia-free water to a second flask to serve as a blank. Treat the contents of each flask as follows. Ad
27、d1.00mL of the phosphate buffer solution(6.3) followed immediately by10.0mL of the naphthoquinone-sulphonate solution(6.2). Allow the mixture to stand for2h in the dark, and then transfer quantitatively to a250mL separating funnel, rinsing the flask with5mL of the ammonia-free water(6.1). Add20.0mL
28、of the chloroform(6.4) to the separating funnel, swirl the contents of the funnel gently fora few seconds, cautiously releasing the pressure generated, and then shake it vigorously for1min. Set the funnel aside in the dark (or otherwise shield from light) to allow phase separation and, when complete
29、, rinse the bore of the separating funnel stopcock by running3mL to5mL of the chloroform extract to waste. Then pass a further2mL to3mL of the chloroform extract to waste through a fast, medium grade filter paper 3)held in a small glass filter funnel, and finally a further portion of the extract thr
30、ough the filter into a dry10mm spectrophotometer cell. Measure the absorbances of the sample and blank at a temperature within1 C of that at which the calibration graph was prepared, using the wavelength used for the calibration graph and10mm cells. Use chloroform in the compensating cell. 9 Calcula
31、tion Deduct the reading obtained for the blank from that for the sample and read off the cyclohexylamine content, in micrograms, from the calibration graph. The concentration, in milligrams per litre, of cyclohexylamine is given by 1) Whatman No.41 paper is suitable. where m is the mass of cyclohexy
32、lamine from the calibration graph (in 4g). V is the volume of the sample (inmL). m V -BS2690-115:1983 BSI 08-1999 3 Appendix A Interference by ammonia Test each batch of solid naphthoquinone-sulphonate reagent for the effect of ammonia, as follows. Place2.5mL of the cyclohexylamine working solution(
33、6.5.2) in each of four100mL flasks. Make additions of standard ammonium chloride solution such that, when made up to a total volume of50mL with the ammonia-free water(6.1), the solutions contain0,0.1,0.2 and0.5mg of ammonia per litre. Determine the cyclohexylamine content of each solution as describ
34、ed in clause8; it should remain constant at54.34g. If a significant error is shown up by this test, determine the ammonia concentration in the sample by the method described in BS2690-7, and carry out the following procedure. To a series of standard cyclohexylamine solutions, prepared as described i
35、n clause7, make additions of a standard solution of ammonium chloride such that the solutions contain the determined amount of ammonia. Determine the apparent cyclohexylamine content of each flask, as described in clause8, and calculate the effect of ammonia. From these results the true cyclohexylam
36、ine content may be determined.4 blankBS2690-115:1983 BSI 08-1999 Publications referred to BS 2690, Methods of testing water used in industry. BS 2690-7, Nitrite, nitrate and ammonia (free, saline and albuminoid) 2) . BS 2690-116, Morpholine: spectrophotometric method 3) . BS 2690-117, Long-chain fat
37、ty amines: spectrophotometric method 3) . 2) Currently being revised. Will be published as Part114. 3) Referred to in the introduction only.BS 2690-115: 1983 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing British
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