UOP 962-1998 COPPER IN GASOLINE AND NAPHTHA BY FLAME-AAS OR ICP-AES.pdf

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1、COPPER IN GASOLINE AND NAPHTHABY FLAME-AAS OR ICP-AESUOP Method 962-98SCOPEThis method is for determining trace concentrations of non-volatile, hydrocarbon soluble forms of copperpresent in gasoline, naphtha, kerosene and similar distillates by either Flame-Atomic AbsorptionSpectrometry (Flame-AAS)

2、or Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Itis particularly useful on products that have been copper sweetened. The lower limit of quantitation is5g/kg (mass-ppb) copper. The method can be extended to other organic materials and concentrationranges. This method can be use

3、d in place of UOP Method 144.OUTLINE OF METHODThe sample is weighed into a beaker, evaporated to dryness and the residue is ashed in a muffle furnace.The ash is dissolved in hydrochloric and nitric acids and analyzed by either Flame-AAS or ICP-AES, usinga freshly prepared standard and blank.APPARATU

4、SReferences to catalog numbers and suppliers are included as a convenience to the method user. Othersuppliers may be used.Atomic absorption spectrophotometer (Flame-AAS), Perkin-Elmer, Model 3110Balance, top-loading, readability 0.01-gBeaker, Vycor, 250-mL, Fisher Scientific, Cat. No. 02-541ACylinde

5、rs, borosilicate glass, Class B, 10- and 25-mL, Fisher Scientific, Cat. Nos. 08-550B and 08-550C,respectivelyFlasks, volumetric, Pyrex, Class A, 100- and 1000-mL, Fisher Scientific, Cat. Nos. 10-210-5C and 10-210-5G, respectivelyFlask, hexagonal base, 25-mL, Pyrex, Fisher Scientific, Cat. No. 20-814

6、GIT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TODETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH ANDSAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THISPROCEDURE IN THE MANNER PRESCRIBED

7、HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS(MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED INTHIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTIONEQUIPMENT (PPE). COPYRIGHT 1998 UOP LLCALL RIGHTS RESERVEDUOP Methods a

8、re available through ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken PA 19428-2959,United States. The Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service atserviceastm.org, 610.832.9555 FAX, or 610.832.9585 PHONE.2 of 6962-98Fun

9、nels, plastic, disposable, 55-mm diameter, Fisher Scientific, Cat. No. 10-320AFurnace, muffle, capable of 500CHollow cathode lamp, copper, Perkin-Elmer, Cat. No. N066-1296Hot plate, capable of 400CInfrared heater, consisting of an infrared (IR) lamp and mountPipets, volumetric transfer, Class A, 10-

10、mL, Fisher Scientific, Cat. No. 13-651-1KSpectrometer, ICP-AES, Perkin-Elmer, Optima 3000Tongs, beaker, Fisher Scientific, Cat. No. 02-620Watch glass, Teflon, 80-mm diameter, Fisher Scientific, Cat. No. 02-617-1GWater purification system, Barnstead NANOpure II, three module, equipped with Pretreatme

11、nt (D0835),Ultrapure (D0809) and Organic Free (D0820) replacement cartridges, for preparing ASTM D 1193type I reagent grade water, Fisher Scientific, Cat. Nos. 09-050-254, 09-034-104, 09-034-3 and 09-034-175K, respectivelyREAGENTS AND MATERIALSAll reagents shall conform to the specifications establi

12、shed by the Committee on Analytical Reagents ofthe American Chemical Society, when such specifications are available, unless otherwise specified.References to water mean ASTM D 1193 type I reagent grade water.References to catalog numbers and suppliers are included as a convenience to the method use

13、r. Othersuppliers may be used.Copper standard solution, 1000-g/mL, SPEX CertiPrep, Cat. No. PLCU2-2XCopper standard solution, 10-g/mL. Pipette 10 mL of 1000-g/mL copper standard solution into a1000-mL volumetric flask containing approximately 250 mL of water. Using a graduated cylinder,carefully add

14、 20 mL of nitric acid and swirl to mix. Fill to volume with water, cap and mix. Thisstandard has a lifetime of one month.Gloves, Silver Shield laminate (HF resistant), available in small (S), medium (M) and large (L) sizes,Fisher Scientific, Cat. Nos. 11-393-65A, -65B and -65C, respectivelyGloves, Z

15、etex (temperature-resistant), Fisher Scientific, Cat. No. 11-392-50Hydrochloric acid, Ultrex II ultrapure reagent, J. T. Baker, Cat. No. 6900-05Hydrofluoric acid, Ultrex II ultrapure reagent, J. T. Baker, Cat. No. 6904-05Nitric acid, Ultrex II ultrapure reagent, J. T. Baker, Cat. No. 6901-053 of 696

16、2-98PROCEDUREAll labware is to be pre-cleaned by boiling in reagent grade 1:1 nitric acid (mix one part Ultrex IIultrapure reagent grade nitric acid with one part water). Extreme care must be taken to controlcontamination. All acids used are to be Ultrex II ultrapure reagent grade or equivalent.Prep

17、aration of Calibration StandardsPrepare a fresh blank and 1-g/mL copper standard each time the analysis is performed.1. Pipette 10 mL of 10-g/mL copper standard solution into 100-mL volumetric flask. Add none to asecond 100-mL flask to be used as the blank.2. Add 15 mL of hydrochloric acid, 1 mL of

18、nitric acid and 30 mL of water to each flask. Swirl to mixthe contents thoroughly.3. Allow to cool, dilute to the mark, cap and mix well.Sample Preparation1. Using a top loading balance, weigh approximately 100 g (record mass to nearest 0.01 g) of sampleinto a 250-mL Vycor beaker.2. Place the beaker

19、 on a cold hot plate in a fume hood and heat slowly to evaporate contents withoutboiling. An infrared (IR) heater may be used to aid in evaporation.3. Turn the hot plate to high (or about 400C) after the volatile components have evaporated, and allowto heat until smoke evolution ceases.4. Place the

20、uncovered beaker in a 500C muffle furnace for a minimum of two hours or until all carbonpresent has burned off.5. Remove the beaker from the muffle furnace and, after the beaker has cooled sufficiently, cover it witha Teflon watch glass. CAUTION: Beaker tongs and temperature-resistant gloves must be

21、 used to remove the hot beakers fromthe muffle furnace.6. Using a 10-mL graduated cylinder, add approximately 7 mL of water, 3.8 mL of hydrochloric acidand 1.2 mL of nitric acid to the beaker. Add two drops of hydrofluoric acid to the beaker. Thencover the beaker with a Teflon watch glass and place

22、on a hot plate. Heat gently for approximately10 minutes, and then to a slow boil. Remove the beaker from the hot plate and allow it to cool. Hydrofluoric acid is used to aid in the dissolution of the ash that may be embedded into the glass walls ofthe beaker. CAUTION: Use appropriate gloves and othe

23、r personal protective equipment (see MSDS)when working with hydrofluoric acid.4 of 6962-987. Transfer the contents, quantitatively, into a 25-mL flask. Fill to volume with water, cap and mix. Note: If an internal standard is required for ICP analysis, add it now. Check with the specific instrumentma

24、nufacturer for recommendations concerning elements, concentrations and wavelengths to be used asinternal standards on their instruments.Copper DeterminationUse either Flame-AAS or ICP-AES to perform the copper determination. See the specific manufacturersinstrument manual for setup instructions. Thi

25、s method assumes the analyst is familiar with the operation ofthe equipment.Flame-AAS AnalysisUse the following operating parameters for the AAS instrument:Copper wavelength, nm 324.754Slit setting, nm 1.3Flame type Air-acetylene (100-mm burner head)Light the flame of the AAS and allow it to stabili

26、ze for 5 minutes. Adjust the burner position whileaspirating a copper standard to achieve maximum response. Read solutions in the following order: blank,standard, samples and then reread the standard as a sample. The final read of the standard should compareto the known concentration to within 3% re

27、lative. If not, reread the series.Note: After reading the standard, it is best to rinse for about a minute. This will reduce the chance ofcopper memory effects. Aspirating a 1% nitric acid rinse between samples will also help reducecopper memory.ICP-AES AnalysisStart the ICP-AES and ignite the plasm

28、a according to the manufacturers recommendations. Allow 15minutes warm up after the plasma is ignited before starting the analysis. Use the copper 324.754 nm linefor the analysis. If an internal standard is being used, use the element, wavelength and concentration levelrecommended by the instrument

29、manufacturer. Aspirate the blank and standard to establish the calibrationcurve prior to the aspiration of the samples. Allow sufficient wash-out time between standards, blanks andsamples to minimize memory effects. Read solutions in the following order: blank, standard, samples andthen reread the s

30、tandard as a sample. The final read of the standard should compare to the knownconcentration to within 3% relative. If not, reread the series.CALCULATIONSCalculate the concentration of copper in the sample, to one significant figure below 10 g/kg, to twosignificant figures between 10 and 990 g/kg an

31、d to three significant figures at or above 1000 g/kg, asfollows:CVCopper, g/kg 1000 M=5 of 6962-98where:C = concentration of copper in solution as determined by the instrument, g/mLM = sample mass, gV = volume of aspirating solution flask, mL1000 = factor to convert g/g (mass-ppm) to g/kg (mass-ppb)

32、PRECISIONASTM RepeatabilityA nested design was carried out for copper analysis using two analysts. Each analyst carried out tests attwo copper concentrations on two separate days, performing two tests each day, using both the AAS andICP. The total number of tests was 16 each using both AAS and ICP.

33、Using a stepwise analysis ofvariance procedure, the within-day estimated standard deviations (esd) were calculated for copper and arelisted in the Table. Two analyses performed in one laboratory by the same analysts on the same day shouldnot differ by more than the ASTM allowable differences shown i

34、n the Table at the concentrations listedwith 95% confidence.UOP RepeatabilityA nested design was carried out for copper analysis by two analysts, with each analyst carrying out testsat two concentrations on two separate days and performing two tests each day, using both the AAS andICP. The total num

35、ber of tests performed was 16 each using both AAS and ICP. Using a stepwise analysisof variance procedure, the within-lab estimated standard deviations (esd) were calculated for copper and arelisted in the Table. Two analyses performed in one laboratory by different analysts on different days should

36、not differ by more than the UOP allowable differences shown in the Table at the concentrations listed with95% confidence.TableASTM and UOP Repeatability, g/kg (mass-ppb)ASTM Repeatability UOP RepeatabilityInstrumentCopperConcentrationWithin-Day esdAllowableDifferenceWithin-Lab esdAllowableDifference

37、AAS 186 6.6 26 7.9 36ICP 178 2.9 11 5.9 26AAS 15 1.1 4 2.3 14ICP 13 1.1 4 0.9 4The data in the Table represent a short-term estimate of repeatability. When the test is run routinely inthe field, a control standard and chart should be used to develop a better estimate of long-term repeatabilityif a s

38、uitable, stable control standard can be maintained.6 of 6962-98ReproducibilityThere is insufficient data to calculate the reproducibility of the test at this time.TIME FOR ANALYSISThe elapsed time for one analysis is four hours. The labor requirement is 0.7 hours for each sample.REFERENCESASTM Metho

39、d D 1193, www.astm.orgUOP Method 144, “Copper in Gasoline and Naphtha”SUGGESTED SUPPLIERSJ. T. Baker, 222 Red School Ln., Phillipsburg, NJ 08865 (908-859-2151)Fisher Scientific, 585 Alpha Dr., Pittsburgh, PA 15238 (412-490-8300)Perkin-Elmer Corp., 761 Main Ave., Norwalk, CT 06859-0270 (203-834-6281)SPEX CertiPrep, Inc., 203 Norcross Ave., Metuchen, NJ 08840-1253 (908-549-7144)