UOP 407-2009 Trace Metals in Organics by Dry Ashing - ICP-OES.pdf

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1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB

2、ED HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS (MSDS) OR EXPERIMENTAL MATERIAL SAFETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 2009 UOP LLC. All rights reserved. Non

3、confidential UOP Methods are available from ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at serviceastm.org, 610.832.9555 FAX, or 610.

4、832.9585 PHONE. Trace Metals in Organics by Dry Ashing - ICP-OES UOP Method 407-09 Scope This method is for determining the concentrations of the metals aluminum (Al), calcium (Ca), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), lithium (Li), magnesium (Mg), manganese (Mn), molybdenu

5、m (Mo), nickel (Ni), palladium (Pd), phosphorus (P), platinum (Pt), potassium (K), sodium (Na), strontium (Sr), tin (Sn), titanium (Ti), vanadium (V), and zinc (Zn) in organic matrices such as crude petroleum, asphalts, vacuum tower bottoms, vacuum gas oils, atmospheric gas oils, diesel and jet fuel

6、s and their blending components, and polymers, by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Most of the elements can be determined within the concentration range of 0.02 to 200 mg/kg when a 50-g sample is ashed. Higher or lower concentrations can be determined by changing s

7、ample weight, dilution volume, and/or modifying the instrument operating parameters. Determination of additional elements is possible if they are not volatilized during the ashing step. See Note. Alternatively, some of the elements listed above may be analyzed by Atomic Absorption Spectroscopy (AAS)

8、. See UOP Method 391, “Trace Metals in Petroleum Products or Organics by AAS,” for specific metals and their range of quantitation. References ASTM Method D482, “Ash from Petroleum Products,” www.astm.org ASTM Method D1193, “Specification for Reagent Water,” www.astm.org UOP Method 389, “Metals in O

9、rganics by Wet Ashing ICP-OES,” www.astm.org UOP Method 391, “Trace Metals in Petroleum Products or Organics by AAS,” www.astm.org UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method The sample is weighed into a quartz beaker. It is ignited and allowed to burn until

10、 it no longer supports a flame. The carbonaceous residue is further treated in a muffle furnace at 540C to complete the ashing. If percent ash is being determined, the empty, full and ignited weights of the beaker are recorded. After ashing, the sample is dissolved in dilute hydrochloric acid contai

11、ning scandium as an internal standard. The concentrations of elements in the resulting solutions are determined by ICP-OES. 2 of 9 407-09 Apparatus Polypropylene labware and containers must be used wherever possible to eliminate the possibility of contamination caused by the leaching of elements fro

12、m glassware. In some instances, propylene labware may not be readily available, e.g., volumetric pipets. Glassware may be used for short-term dispensing purposes if it is cleaned before and after use. Glassware must never be used for storage of calibration solutions or samples. References to catalog

13、 numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Balance, readability 0.001-g Beakers, quartz, low form, 250-mL, Ace Glass, Inc., Cat. No. 5334-14 Bottles, polypropylene, narrow mouth, screw cap, 30-mL, VWR, Cat. No. 16067-022 Bottle, wash, VWR, C

14、at. No. 16651-595, for deionized water Cylinder, graduated, polypropylene, 10-mL, VWR, Cat. No. 83008-860 Desiccator, VWR, Cat. No. 25021-022, with high temperature plate, VWR, Cat. No. 89038-070 Flasks, volumetric, polypropylene, 50-, 100-, and 1000-mL, VWR, Cat. Nos. 29615-018, -007, and -062, res

15、pectively, several of each required Furnace, muffle, capable of operation at 540C, VWR, Cat. No. 30604-158 Gloves, thermal protection, VWR, Cat. No. 32885-407, optional Hot plate, variable heat, maximum operating temperature 510C, VWR, Cat. No. 82026-752 Meker burner, VWR, Cat. No. 89038-544 Pipets,

16、 Mohr, polypropylene, 1- and 10-mL, Thomas, Cat. Nos. 7480N48 and 7480N84, respectively Pipets, volumetric, Class A, 5, 10- and 100-mL, VWR, Cat. Nos. 89045-064, -074, and -088, respectively Pipet filler, VWR, Cat. No. 53497-053 Regulator, argon, two-stage, high purity, delivery pressure range 30-70

17、0 kPa (4-100 psi), Matheson Tri-Gas, Model 3122-580 Spectrometer, ICP-OES, computer controlled, having sufficient resolving power and dispersion to separate the analytical lines in the 160 to 800 nm region. The data system shall be capable of performing background corrections, blank corrections, mas

18、s/volume corrections and dilution corrections. A commercial grating spectrometer with a band pass of 0.018 nm or less in the first order is satisfactory. PerkinElmer Optima 5300 V. Stirring rods, quartz, JSRitter, Cat. No. 21-905 Support, cast iron tripod, VWR, Cat. No. 62760-003 Support, wire gauze

19、, VWR, Cat. No. 66232-029 Watch glasses, ribbed, 75-mm diameter, Wilmad-LabGlass, Cat. No. C-9990-75 Tongs, beaker, VWR, Cat. No. 82027-372 3 of 9 407-09 Reagents and Materials References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used.

20、Unless otherwise specified, references to water mean deionized water. Argon, 99.995% minimum purity Cleaning compound, Alconox detergent, VWR, Cat. No. 21835-032. Dilute 1:100 in deionized water for use. Desiccant, VWR, Cat. No. EM-DX0017-1 Gloves, neoprene/natural rubber, VWR, Cat. No. 32917-206 (f

21、or size large) Hydrochloric acid, HCl, concentrated, high purity, VWR, Cat. No. VW3110-3 Hydrochloric acid, diluted to 1 in 10. Fill a 1000-mL volumetric flask approximately half full with deionized water. Pipet 100 mL of concentrated HCl into the flask. Dilute to the mark with deionized water. Natu

22、ral gas, for Meker burner Nitric acid, HNO3, concentrated, high purity, VWR, Cat. No. VW4815-6 Scandium metal solution, aqueous, 1000-g/mL, SPEX Industries, Inc., Cat. No. PLSC-2, for use as internal standard Scandium internal standard solution, 100-g/mL. To prepare 1000 mL, pipet 100.0 mL of 1000-g

23、/mL scandium solution into a 1000-mL volumetric flask. Using a graduated cylinder, add 100 mL of concentrated hydrochloric acid. Fill to the volume mark with water and mix. Store in a 1000-mL polypropylene bottle. Scandium internal standard solution, 10-g/mL. To prepare 1000 mL, pipet 10.0 mL of 100

24、0-g/mL scandium solution into a 1000-mL volumetric flask. Using a graduated cylinder, add 100 mL of concentrated hydrochloric acid. Fill to the volume mark with water and mix. Store in a 1000-mL polypropylene bottle. Standard metal solutions, Al, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb,

25、 Pd, Pt, Sn, Sr, Ti, V, and Zn solutions of 1000-g/mL concentrations. SPEX Industries, Inc., Cat. Nos. PLAL2-2, PLCA2-2, PLCO2-2, PLCR2-2, PLCU2-2, PLFE2-2, PLK2-2, PLLI2-2, PLMG2-2, PLMN2-2, PLMO2-2, PLNA2-2, PLNI2-2, PLP2-2, PLPB2-2, PLPD2-2, PLPT2-2, PLSN2-2, PLSR2-2, PLTI2-2, PLV2-2, and PLZN2-2

26、, respectively Pipets, disposable transfer, VWR, Cat. No. 16001-188 Water, deionized, ASTM D1193 Type III reagent grade water, unless otherwise specified The following materials are not required to perform the analyses described herein and are not cited in the Procedure portion of the method. Howeve

27、r, they may be useful for reference purposes, for verification of instrument performance, or as an aid in instrument maintenance. The diluted multi-element standard was used to develop part of the precision statement. Element Blank Oil, 75 viscosity, Conostan Division Wear Metal Multi-Element Standa

28、rd, 500-g/g (mg/kg) each, AccuStandard, Cat. No. WM-21-50X-8. Dilute by weight in Element Blank Oil to 5-mg/kg. 4 of 9 407-09 Procedure The analyst is expected to be familiar with general laboratory practices, the technique of ICP-OES, and the equipment being used. CAUTION: All subsequent steps invo

29、lving heating of samples and addition of acids must be performed in a properly operating fume hood, and appropriate personal protective equipment must be worn. See MSDS for each material used. Preparation of Standards Standards are required for each element to be determined. Standards are prepared t

30、o contain a number of elements with compatible chemistries and no overlap of emission lines. Stock standard solutions are prepared first, from which lower level, matrix matched, calibration standard solutions are then prepared. Preparation of Stock Standard Solutions Prepare stock standard solutions

31、 of 100-g/mL concentration of each element as follows: 1. Pipet 100 mL each of the Al, Ca, Co, Cr, Cu, Fe, Mg, Mn, and Ni 1000-g/mL commercial stock standards into a 1000-mL polypropylene volumetric flask. Dilute to the mark with deionized water. Label as Stock Standard A. 2. Pipet 100 mL each of th

32、e K, Li, Na, P, Ti, V, and Zn 1000-g/mL commercial stock standards into a second 1000-mL polypropylene volumetric flask. Dilute to the mark with deionized water. Label as Stock Standard B. 3. Pipet 100 mL each of the Mo, Pb, Sn, and Sr 1000-g/mL commercial stock standards into a third 1000-mL polypr

33、opylene volumetric flask. Dilute to the mark with deionized water. Label as Stock Standard C. 4. Pipet 100 mL each of the Pd and Pt 1000-g/mL commercial stock standards into a fourth 1000-mL polypropylene volumetric flask. Dilute to the mark with deionized water. Label as Stock Standard D. Preparati

34、on of Blank and Calibration Standard Solutions Prepare 100 mL of matrix matched calibration standards and a blank as follows: 1. Label five 100-mL polypropylene volumteric flasks 10-mg/kg Calibration Standard A, B, C, D, and Blank. 2. Pipet into each of the five flasks 1.0 mL of the 1,000-g/mL scand

35、ium solution. 3. Pipet 10.0 mL of Stock Standard A into the flask labeled 10-mg/kg Calibration Standard A. Fill to the mark with diluted HCl. Follow the same procedure for Standards B, C, and D. The standards contain 10.0 g/mL of their respective elements. Fill the flask labeled Blank to the mark wi

36、th diluted HCl. Preparation of Spectrometer Start up the ICP-OES and ignite the plasma according to the manufacturers recommendations. Allow a minimum of 30 minutes for warm up after the plasma is ignited before starting the analysis. Using the recommended elemental emission wavelengths, calibrate t

37、he spectrometer prior to the analysis of the sample solution. Perform a wavelength calibration prior to the start of the analysis if 5 of 9 407-09 recommended by the manufacturer. Aspirate the standards and blank to establish the calibration for each element to be measured. Table 1 lists recommended

38、 wavelengths to be used for the analyses. Preparation of Quartz Beakers Clean the 250-mL quartz beakers before each use as follows: 1. Wash the beakers with cleaning compound and rinse with deionized water. 2. Using a graduated cylinder, add 10 mL of concentrated hydrochloric acid, bring to boiling

39、on a hot plate and allow to cool. Rinse again 4 to 5 times with deionized water. Dispose of the hydrochloric acid and all other chemicals used in an environmentally safe manner according to local regulations. 3. Store in a clean area. Table 1 Recommended Wavelengths for each Element Element Concentr

40、ation Range in Sample, mg/kg* , nm Element Concentration Range in Sample, mg/kg* , nm Al 0.05-500 396.152 Na 0.05-500 589.592 Ca (low) 0.05-5 393.366 Ni 0.10-100 231.604 Ca (high) 5.0-500 422.673 P 0.10-500 Co 0.05-200 228.616 Cr 0.05-50 206.149 213.618 or 214.914 Cu 0.02-200 324.754 Pb 0.10-100 220

41、.353 Fe 0.02-200 238.204 Pd 0.05-200 340.458 K 0.05-500 766.491 Pt 0.05-200 265.945 Li 0.02-200 Sc internal standard 424.683 Sn 0.20-200 189.989 610.364 or 670.781 Sr 0.02-200 407.771 Mg 0.02-200 279.553 Ti 0.20-200 334.941 Mn 0.02-200 257.610 V 0.02-200 292.402 Mo 0.05-50 202.030 Zn 0.02-200 206.20

42、0 * Based on an ashed 50-g sample, diluted to 50 mL for the higher concentrations and 10 mL for the lower concentrations. Sampling Sample size depends primarily on the type of sample and the concentrations of metals expected to be present. Several sample types and amounts used, based upon typical me

43、tals concentrations, are listed in Table 2. Because elements can be extracted from glass, the sample should be collected in plastic bottles. Weigh into a quartz beaker, to the nearest 0.01 g, an amount of sample appropriate to sample type and the expected metals concentration. See Table 2. Ensure th

44、at a representative sample is obtained. Viscous samples may be gently heated until they flow freely. Hot tap water is generally satisfactory, however, more viscous samples may require use of 6 of 9 407-09 boiling water. Shake the warmed samples vigorously or stir with a quartz rod and then weigh a s

45、ample for analysis to the nearest 0.01 g. Contamination is possible especially because of the trace concentrations, in many cases sub-mass-ppm, of common metals. If sufficient sample is available, duplicate ananlyses may be performed as a check. If duplicate analyses are performed, report the indivi

46、dual results. Table 2 Sample Types and Sample Size Used Sample Amount used, g Sample Amount used, g Crude Petroleum 5 to 10 Atmospheric Gas Oil 50 to 100 Asphalt 5 to 10 Diesel and Jet Fuel 50 to 100 Vacuum Tower Bottoms 5 to 10 Polymers 5 to 10 Vacuum Gas Oil 20 to 50 Sample Preparation, Dry Ashing

47、 Determination of Percent Ash, if Requested 1. Heat the quartz beakers that are to be used for ashing the sample at 540C for a minimum of 10 minutes. 2. Remove from furnace, place in a descicator, cool to room temperature and weigh to 0.001 g. 3. Add sample and record the weight. Weigh after ignitio

48、n, see Dry Ashing, and calculate % ash, if requested, and report % ash and the temperature used. Make all weighings to the nearest 0.001 g. If the determination of % ash is not requested, weighing the sample to the nearest 0.01 g is suffucient for metals analysis. Dry Ashing Dry ash the samples as d

49、escribed below. Additional information about dry ashing is available in ASTM Method D482, “Ash from Petroleum Products.” 1. Turn on the muffle furnace and set the temperature at 540C. The muffle furnace must be used in a hood. 2. Ignite and ash the sample: - In a hood, carefully heat the quartz beaker containing the sample with a Meker burner, or equivalent, until the contents are ignited. - Maintain the temperature so that the sample continues to burn at a uniform and moderate rate. Only a carbonaceous residue is present when the burning c