1、BRITISH STANDARD BS3762-3.10: 1989 Analysis of formulated detergents Part3: Quantitative test methods Section3.10 Methods for determination of short-chain alkylbenzenesulphonates content NOTEIt is recommended that this Section be read in conjunction with the information in the“General introduction”,
2、 published separately as BS3762-0. UDC661.185.6:620.1BS3762-3.10:1989 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authorityofthe Board of BSIandcomesinto effect on 28February1989 BSI11-1999 The committees responsible fo
3、rthis British Standard are shown in Part0. The following BSI references relate to the work on this standard: Committee reference CIC/34 Draft for comment87/51478 DC ISBN 0 580 17077 2 Foreword This Section of BS3762 has been prepared under the direction of the Chemicals Standards Committee and super
4、sedes method B8 of BS3762:1964, which is being deleted by amendment. This standard describes methods of test only and should not be referred to as a specification defining limits of purity. Reference to the standard should indicate that the method of test used is in conformity with BS3762-3.10. A Br
5、itish Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are 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 fr
6、ont cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been 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 publicatio
7、n Amd. No. Date of issue CommentsBS3762-3.10:1989 BSI 11-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 Method A: spectrometry 1 3 Method B: high performance liquid chromatography (HPLC) 2 4 Precision 3 5 Test report 3 Figure 1 Typical chromatogram 4 Publications referred to Inside bac
8、k coverii blankBS3762-3.10:1989 BSI 11-1999 1 1 Scope This Section of BS3762 describes two methods for the determination of the toluenesulphonates or xylenesulphonates content of formulated detergents. In method A, the alkylbenzenesulphonates content is determined spectrometrically as sodium toluene
9、sulphonate or as sodium xylenesulphonate, using calibration graphs prepared with appropriate reference materials. Method B, which is based on a reversed-phase high-performance liquid chromatographic (HPLC) separation technique, separates and quantifies mixtures. Method A is for use if no HPLC equipm
10、ent is available, or if mixtures of toluenesulphonates and xylenesulphonates are not suspected. Method A is not applicable to samples containing compounds that absorb radiation at220nm and that are not extracted by diethyl ether, e.g.alkylphenolethoxylates. Method B may be used with samples that con
11、tain single or mixed compounds. NOTEThe titles of the publications referred to in this Section are listed on the inside back cover. 2 Method A: spectrometry 2.1 Principle Toluenesulphonate or xylenesulphonate is determined by ultraviolet spectrometry after extraction of alkylarylsulphonates with die
12、thyl ether from a solution of the product in dilute hydrochloric acid solution. 2.2 Reagents The reagents other than those described in2.2.4 and2.2.5 shall be of a recognized analytical grade. Water complying with grade3 of BS3978 shall be used throughout. 2.2.1 Diethyl ether 2.2.2 Acetone 2.2.3 Mix
13、ed solvent. Mix one volume of absolute ethanol with one volume of acetone. 2.2.4 Sodium toluenesulphonate, pure. NOTEThis will normally be sodium p-toluenesulphonate but may be another isomer. 2.2.5 Sodium xylenesulphonate, pure. NOTEThis will normally be a mixture of isomers. 2.2.6 Sodium hydroxide
14、 solution,100g/L. 2.2.7 Hydrochloric acid solution, c (HCl)=6mol/L. 2.2.8 Hydrochloric acid solution, c (HCl)=4mol/L. 2.2.9 Narrow range indicator paper, pH4 to6. NOTEA correctly calibrated pH meter is a suitable alternative. 2.3 Apparatus Ordinary laboratory apparatus and the following are required
15、. 2.3.1 Spectrometer, suitable for measurements between200nm and280nm. 2.3.2 Silica cells, optical path length10mm. 2.3.3 Sintered glass filter, complying with grade P16 of BS1752. 2.3.4 One-mark volumetric flasks,100mL and250mL, complying with grade A of BS1792. 2.4 Procedure 2.4.1 Test solution. W
16、eigh, to the nearest0.01g, about10g of well mixed sample into a beaker. Dissolve it in water, transfer the solution quantitatively to a250mL one-mark volumetric flask(2.3.4) and dilute to the mark with water. Mixwell. 2.4.2 Removal of alkylarylsulphonates CAUTION. Perform all extractions with diethy
17、l ether with due regard to possible fire hazard and preferably in an area free of ignition sources. Transfer by pipette50mL of the test solution(2.4.1) to a separating funnel, add25mL of the hydrochloric acid solution(2.2.7) and extract with50mL of the diethyl ether(2.2.1). Transfer the aqueous (low
18、er) phase to a second separating funnel and retain the ether phase. Repeat the extraction of the aqueous phase with a further three50mL portions of the diethyl ether. Combine the four diethyl ether extracts in a separating funnel and wash three times with25mL portions of the hydrochloric acid soluti
19、on(2.2.8). Combine the wash liquors and extract with50mL of the diethyl ether. Discard the ether extract. 2.4.3 Extraction of short-chain alkylbenzenesulphonates. Evaporate to dryness the aqueous phase and washings recovered from the extraction, preferably using a rotary evaporator. NOTEThe washings
20、 will be saturated with diethyl ether, so suitable precautions should be taken to allow for a possible hazard from the evolution of diethyl ether vapour. Dissolve the residue in a little water and neutralize with the sodium hydroxide solution(2.2.6) until the pH value is4.5, as indicated by the narr
21、ow range indicator paper(2.2.9). Evaporate to dryness, add5mL of the acetone(2.2.2), evaporate to dryness again and repeat twice more with fresh5mL portions of the acetone.BS3762-3.10:1989 2 BSI 11-1999 Add50mL of the mixed solvent(2.2.3) to the residue, heat on a steam bath or hot plate at100 C for
22、 about10min, then remove and allow insoluble matter to settle. Decant the solution through the sintered glass filter(2.3.3), to which gentle suction is applied. Extract the residue with four successive30mL portions of the mixed solvent, passing each in turn through the sintered glass filter. Wash th
23、e filter three times with mixed solvent, heated to about50 C. Evaporate the filtrate and washings to dryness and dissolve the residue in water. Transfer the solution quantitatively to the100mL one-mark volumetric flask(2.3.4) and dilute to the mark with water. Mixwell. 2.4.4 Spectrometric analysis.
24、Produce a calibration graph by preparing a range of solutions of toluenesulphonate or xylenesulphonate reference material(2.2.4 or2.2.5), as appropriate. The concentrations should cover a range corresponding to absorbances of0.0 to approximately0.8. Determine the absorbance of each solution at220nm,
25、 using the silica cells(2.3.2), and with water as a reference blank. Plot a calibration graph of concentration versus absorbance. NOTE 1Four or five solutions should be used. Determine the absorbance at220nm of the solution obtained from2.4.2, using the silica cells(2.3.2), and with the distilled wa
26、ter as a reference blank. Ifnecessary, prepare serially diluted solutions to bring the absorbance readings within the range of the calibration graph. Determine the concentration of toluenesulphonate or xylenesulphonate in the test solution from the graph. NOTE 2Toluenesulphonates may be distinguishe
27、d from xylenesulphonates as they have different ultraviolet spectra. Thetoluene derivatives give maxima at220nm,256nm,262nm and268nm and the xylene derivatives give maxima at220nm,272nm and278nm. 2.5 Expression of results The toluenesulphonate or xylenesulphonate content, expressed as a percentage b
28、y mass as the sodium salt, is given by the following expression: 3 Method B: high performance liquid chromatography (HPLC) 3.1 Principle Separation of the desired compound by reversed-phase HPLC, with ultraviolet detection and comparison of the sample peak areas with those derived from suitable exte
29、rnal reference standards. 3.2 Reagents The reagents other than those described in3.2.3 and3.2.4 shall be of a recognized analytical grade. Water complying with grade1 of BS3978 shall be used throughout. NOTESolvents and water of HPLC grade are commercially available and may be used. 3.2.1 Methanol 3
30、.2.2 Mobile phase, of a composition to effect suitable elution of the desired species. An example is methanol/water 25:75(V/V), containing ammonium acetate(10g/L of methanol/water). 3.2.3 Sodium toluenesulphonate, pure. NOTEThis will normally be sodium p-toluenesulphonate but may be another isomer.
31、3.2.4 Sodium xylenesulphonate, pure. NOTEThis will normally be a mixture of isomers. 3.3 Apparatus Ordinary laboratory apparatus and the following are required. 3.3.1 High performance liquid chromatograph, with the following elements. 3.3.1.1 Stainless steel column, of suitable dimensions, typically
32、100mm long and of4.6mm internal diameter, packed with octadecyl-modified fully end-capped silica-based packing of54m mean particle size, or similar suitable packing. NOTE 1Such columns are available commercially. NOTE 2A short precolumn to protect the analytical column may be used. This should be pa
33、cked with material similar in surface modification to that in the main column. 3.3.1.2 Injection valve, fitted with a fixed volume104L loop, or capable of operation in the partial loop filling mode with a loop volume of not less than204L. NOTEAlternatively, a suitable automatic injection system may
34、be used. 3.3.1.3 Ultraviolet detector, capable of measuring absorbance at254nm. 3.3.2 Syringe, of254L,504L or1004L capacity, with needle to suit the loading requirements of the injection valve, unless automatic injection is used. 3.3.3 Chart recorder or plotter 3.3.4 Peak integrator, preferably elec
35、tronic. 3.3.5 One-mark volumetric flasks,100mL and250mL, complying with BS1792. where d is the dilution factor (unity if no dilution was used in2.4.4); c is the concentration of sodium toluenesulphonate or sodium xylenesulphonate found from sample absorbance and the calibration graph (see2.4.4) (ing
36、/100mL); m is the mass of sample taken (see2.4.1) (ing). 500d c m -BS3762-3.10:1989 BSI 11-1999 3 3.4 Procedure 3.4.1 Test solution. Weigh, to the nearest0.01g, about10g of well mixed sample into a beaker. Dissolve it in water, filter it if necessary using a fine glass-fibre filter paper, transfer i
37、t quantitatively to a250mL one-mark volumetric flask(3.3.5) and dilute to the mark with water. Mix well. 3.4.2 Preparation of external reference standard solutions. Weigh, to the nearest0.0002g, about0.1g of the sodium toluenesulphonate(3.2.3) or weigh, to the nearest0.001g, about0.5g of the sodium
38、xylenesulphonate(3.2.4) as required, into a100mL beaker. Dissolve the reference material in water, transfer it quantitatively to a100mL one-mark volumetric flask(3.3.5) and dilute to the mark with water. Mix well. NOTE 1Make both solutions separately if both types of sulphonate are to be determined.
39、 NOTE 2For successful calibration using single-level reference standards, the system response has to be linear. It is recommended that a suitable serial dilution of the reference standard and sample solutions be made if the absorbance figures obtained exceed1.0. If there is any doubt concerning syst
40、em linearity, make up a series of reference standard solutions at suitable concentrations to produce a graph of response versus concentration. 3.4.3 Chromatographic conditions. The following conditions are given as examples and have been found to be suitable. 3.4.4 Chromatographic analysis. Commence
41、 pumping the modile phase(3.2.2) at the chosen flow rate and allow the conditions to stabilize. Using the appropriate procedure for the injection system, load the sample loop with the required reference standard solution(3.4.2). Simultaneously start data collection by the integrator(3.3.4) and opera
42、te the injection valve(3.3.1.2). Allow the chromatogram to develop and obtain the peak areas from the integrator. Repeat the procedure for the sample solution. An example of a chromatogram that may be obtained, depending on the species present, is shown inFigure 1. After a number of analyses, typica
43、lly six to ten, wash the column free of retained material, including long-chain alkylbenzenesulphonates. Change the eluent to the methanol(3.2.1) and pump at the same or higher flow rate until conditions have restabilized. Change the eluent back to the mobile phase(3.2.2) and allow conditions to sta
44、bilize again at the chosen flow rate before further analyses. 3.5 Expression of results The toluenesulphonate or xylenesulphonate content, expressed as a percentage by mass as the sodium salt, is given by the following expression: 3.6 Typical chromatogram Figure 1 shows a chromatogram that is typica
45、l of those obtained from a sample containing impure sodium xylenesulphonate, with sodium toluenesulphonate included in the impurities. 4 Precision No precision data are available. 5 Test report The test report shall include the following information: a) a reference to this British Standard, i.e.BS37
46、62-3.10:1989; b) a reference to the test method used, i.e.methodA or method B; c) the results expressed in accordance with2.5 or3.5, including the reference standard used, i.e.either as sodium toluenesulphonate or as sodium xylenesulphonate, and the isomeric nature of the reference standard (this wi
47、ll normally be as p-toluenesulphonate or as xylenesulphonate, mixed isomers); d) a complete identification of the sample. Eluent flow rate 1.5mL/min Detector wavelength 254nm (alternatively220nm giving greater sensitivity, requiring different dilutions) Injection volume 104L where a 2 is the peak ar
48、ea for the sample, using the same peaks as the reference standard, identified by retention time; m 1 is the mass of the reference material weighed in3.4.2 (ing); a 1 is the peak area for the reference standard (for xylenesulphonate, the total of the peaks due to the isomers); m 2 is the mass of the
49、sample weighed in3.4.1 (ing). 250a 2 m 1 a 1 m 2 -BS3762-3.10:1989 4 BSI 11-1999 Figure 1 Typical chromatogramBS3762-3.10:1989 BSI 11-1999 Publications referred to BS1752, Specification for laboratory sintered or fritted filters including porosity grading. BS1792, Specification for one-mark volumetric flasks. BS3978, Specification for water for laboratory use. BS3762-3.10: 1989 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsibl
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