1、PALLADIUM, GOLD AND POTASSIUM INSILICA CATALYST BY ICP-AESUOP Method 916-93SCOPEThis method is for determining palladium, gold and potassium in fresh silica catalyst by InductivelyCoupled Plasma-Atomic Emission Spectrometry (ICP-AES). The method is suitable for the concentrationranges of 0.2 to 1 ma
2、ss-% palladium, 0.1 to 0.5 mass-% gold and 1 to 5 mass-% potassium. Catalystscontaining more than 1% alumina cannot be analyzed by this method.OUTLINE OF METHODA representative sample of fresh whole pill catalyst is obtained and ground according to UOP Method918. A portion of the ground sample is fu
3、med with hydrofluoric and sulfuric acids and the residue isdissolved in hydrochloric and nitric acids. Scandium is added as an internal standard. The sample solution isaspirated into a computer controlled ICP-AES along with a matrix-matched standard. Concentrations aredetermined by comparison of the
4、 sample emission ratios to the computer-generated standard calibrationcurves. Results are reported on a volatile-free basis at 700C, following duplicate loss on ignition (LOI)determinations by UOP Method 909.APPARATUSReferences to catalog numbers and suppliers are included as a convenience to the me
5、thod user. Othersuppliers may be used.Balance, electronic, readability 0.1-mg, 200-g capacityBalance, electronic, top-loading, readability 0.01-g, 2100-g capacityBeaker, borosilicate glass, 400-mLBeakers, Teflon (TFE), 250-mL, Fisher Scientific, Cat. No. 02-593-5BBottle, narrow mouth, round, amber g
6、lass, 237-mL, with molded plastic conical polyethylene lined cap,Fisher Scientific, Cat. No. 03-320-6CBottle, polyethylene, right-to-know safety wash, distilled water, 500-mL, Fisher Scientific, Cat. No. 03-409-11EIT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO
7、DETERMINE 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 HEREIN CAN BE HAZARDOUS. MATERIAL SAFETY DATA SHEETS(MSDS) OR EXPERIMENTAL MATERIAL SAF
8、ETY DATA SHEETS (EMSDS) FOR ALL OF THE MATERIALS USED INTHIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTIONEQUIPMENT (PPE). COPYRIGHT 1993 UOP LLCALL RIGHTS RESERVEDUOP Methods are available through ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
9、ohocken 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 10916-93Buret, weighing, 10-mL, Kimble No. 17200-F10, Scientific Products, Cat. No. B9366-10Cylin
10、der, graduated, borosilicate glass, Class A, 1000-mL, Fisher Scientific, Cat. No. 08-553DCylinder, graduated, polypropylene, 25-mL, Fisher Scientific, Cat. No. 08-572-6BFlask, Kjeldahl, 100-mL, Fisher Scientific, Cat. No. 10-110CFlasks, volumetric, Class A, 100- and 1000-mL, Fisher Scientific, Cat.
11、Nos. 10-210-5C and -5G,respectivelyFunnel, filter, 58 angle bowl, short stem, 75-mm diameter, Fisher Scientific, Cat. No. 10-322EHot plate-stirrer, digital, Dataplate, 9-positions, Scientific Products, Cat. No. H2185-6Inductively Coupled Plasma-Atomic Emission Spectrometer, computer controlled, havi
12、ng a bandpass of0.010 nm (FWHM) or better, and covering the wavelength range specified in Table 1. The instrumentmust have the ability to use internal standards and perform background corrections, and must measurethe internal standard response concurrently with each element response. A Perkin-Elmer
13、Plasma 2000spectrometer with a corrosion resistant sample introduction system, or its equivalent, is required.Petri dish, Fisher Scientific, Cat. No. 08-747FPipetter, motorized, digital, Rainin, Cat. No. EP-10mL, with portable power pack, Cat. No. 6100-080,rapid charge stand, Cat. No. 6101-049 and p
14、ipet tips, Cat. No. RC-10mLPipetter, repeater, 5-, 10- and 25-mL, Fisher Scientific, Cat. Nos. 13-683-10B, -10C and -10F,respectivelyRegulator, argon, two-stage, high purity, Matheson Gas Products, Model 3104-580Regulator, nitrogen, two-stage, high purity, Matheson Gas Products, Model 3104-580Scoop,
15、 weighing, 20-g capacity, nickel alloy, Fisher Scientific, Cat. No. 01-914-38Spatula, Scoopula, 150-mm, Fisher Scientific, Cat. No. 14-357Stirring bars, magnetic, borosilicate glass, 6-mm OD x 21-mm, and 9.55-mm OD x 25.4-mm, ScientificProducts, Cat. Nos. S8313-31 and -33, respectivelyStirring bars,
16、 magnetic, Teflon, 38-mm, Fisher Scientific, Cat. No. 14-511-64Thermometer, surface, with temperature probe, Omega Engineering, Cat. Nos. HH81 and 88108K,respectivelyTongs, beakerWatch glass, Pyro-quartz, triple-rib, 90-mm diameter, rim to center (curvature) height approximately 25mm, Pyromatics, Ca
17、t. No. PI-7206REAGENTS AND MATERIALSAll reagents shall conform to the specifications established by the Committee on Analytical Reagents ofthe American Chemical Society, when such specifications are available, unless otherwise specified.References to water mean deionized or distilled water, except w
18、here noted.References to catalog numbers and suppliers are included as a convenience to the method user. Othersuppliers may be used.Acetone, 99.5% minimum purity3 of 10916-93Argon, 99.995% minimum purity, ICP feed gasGold wire, 0.25-mm diameter, high purity, 99.998%, Aesar, Cat. No. 10967Hydrochlori
19、c acid, concentrated, 37%Hydrochloric acid, 1:1. Add 500 mL of concentrated hydrochloric acid, measured in a graduatedcylinder, to an equal volume of water in a volumetric flask and mix.Hydrofluoric acid, concentrated, 48-51%Hydrogen peroxide, concentrated, 30%Nitric acid, concentrated, 70%Nitrogen,
20、 99.99% minimum purity, water/oil free, ICP optics purge gasPalladium wire, 0.25-mm diameter, high purity, 99.997%, Aesar, Cat. No. 10962Potassium standard, custom grade standard, 10-mg/mL, Inorganic Ventures, Inc., Cat. No. CGK10-5.The relative density information on the label is needed for prepara
21、tion of the Reference Standard on amass basis.Scandium standard, custom grade standard, 1000-g/mL, Inorganic Ventures, Inc., Cat. No. CGSC1-5Sulfuric acid, concentrated, 98%Sulfuric acid, 1:1. Carefully, and with ice-cooling, pour 500 mL of concentrated sulfuric acid into 500mL of water, mix and all
22、ow to cool. The mixture may be stored indefinitely in a well stoppered bottleor flask.PROCEDUREAll subsequent steps involving handling and heating of concentrated acids or acid solutions must beperformed in a fume hood.Preparation of Calibration StandardsPalladium Standard Solution (1-mg/g)1. Weigh
23、1.0 g of 99.997% palladium wire to the nearest 0.1 mg.2. Transfer the palladium wire into a 100-mL Kjeldahl flask and add a small borosilicate glass magneticstir bar.3. Add 25 mL of hydrochloric acid and 10 mL of nitric acid to the flask. Place the flask in a 400-mLbeaker. Treatment of the palladium
24、 is conducted at ambient temperature until evolution of chlorine has subsided. If allowed to sit overnight, the palladium may dissolve without heating.4. Place the flask and beaker on a stirring hot plate and heat to a gentle boil while stirring slowly.5. Maintain the solution volume at approximatel
25、y 30 mL by the dropwise addition of concentrated nitricand hydrochloric acid in a ratio of 2 to 5, respectively, until the palladium wire dissolves. Caution must be exercised during the addition of the acids to avoid spattering of the palladium solution.4 of 10916-936. Evaporate the acid solution sl
26、owly to approximately 20 mL by gentle boiling.7. Add 30 mL of water and 20 mL of hydrochloric acid to the solution. Swirl to mix.8. Remove the flask and beaker from the hot plate and allow them to cool to ambient temperature.9. Tare a one-liter volumetric flask to the nearest 0.01 g and transfer the
27、 palladium solutionquantitatively with water to the flask.10. Add 30 mL of concentrated hydrochloric acid to the solution.11. Dilute with water to a mass that will produce a palladium concentration of exactly 1.000 mgpalladium per gram of solution, weighed to the nearest 0.01 g. The final mass of th
28、e palladium solution is equal to the mass of the palladium wire multiplied by 1000. Forexample, if 1.0034 g of palladium wire were dissolved, the final mass of the palladium solution would be1003.40 g.12. Mix the solution thoroughly by shaking.13. Subdivide the palladium standard solution without di
29、lution, into separate 237-mL (or smaller) amberglass bottles and seal with polyethylene lined caps. The stability of the solution in an unopened bottle is not known. The working standard in use, willdeteriorate with time and cannot be used for longer than 4 weeks.Gold Standard Solution (1-mg/g)1. We
30、igh 1.0 g of 99.998% gold wire to the nearest 0.1 mg.2. Transfer the gold wire into a 100-mL Kjeldahl flask and add a small borosilicate glass magnetic stirbar.3. Add 25 mL of hydrochloric acid and 10 mL of nitric acid to the flask. Place the flask in a 400-mLbeaker. Treatment of the gold is conduct
31、ed at ambient temperature until evolution of chlorine has subsided.4. Place the flask and beaker on a stirring hot plate and heat to a gentle boil while stirring slowly.5. Maintain the solution volume at approximately 30 mL by the dropwise addition of concentrated nitricand hydrochloric acid in a ra
32、tio of 2 to 5, respectively, until the gold wire dissolves. Caution must be exercised during the addition of the acids to avoid spattering of the gold solution.6. Evaporate the acid solution slowly to approximately 20 mL by gentle boiling.7. Add 30 mL of water and 20 mL of hydrochloric acid to the s
33、olution. Swirl to mix.8. Remove the flask and beaker from the hot plate and allow them to cool to ambient temperature.9. Tare a one-liter volumetric flask to the nearest 0.01 g and transfer the gold solution quantitativelywith water to the flask.10. Add 30 mL of concentrated hydrochloric acid to the
34、 solution.11. Dilute with water to a mass that will produce a gold concentration of exactly 1.000 mg gold per gramof solution, weighed to the nearest 0.01 g.5 of 10916-93 The final mass of the gold solution is equal to the mass of the gold wire multiplied by 1000. For example, if1.0034 g of gold wir
35、e were dissolved, the final mass of the gold solution would be 1003.40 g.12. Mix the solution thoroughly by shaking.13. Subdivide the gold standard solution without dilution, into separate 237-mL (or smaller) amber glassbottles, seal with polyethylene lined caps and store in a dark place. The stabil
36、ity of the solution in an unopened bottle is not known. The working standard in use, willdeteriorate with time and cannot be used for longer than 4 weeks.Potassium-Palladium-Gold reference Standard SolutionThe Reference Standard must be prepared fresh daily, and should closely match the catalyst sam
37、plesolution composition. In addition, the acid content and scandium (internal standard) levels must be matchedbetween samples and standards. In the example below, the Reference Standard is prepared to containapproximately 600 g K/mL, 100 g Pd/mL, 50 g Au/mL and 50 g Sc/mL (the latter as an internals
38、tandard) as follows:1. Pour 6 mL of 10-mg/mL potassium standard into a weighing buret.2. Tare the weighing buret on the analytical balance to read zero.3. Carefully transfer and drain the entire solution into a 100-mL volumetric flask.4. Place the empty weighing buret on the analytical balance and r
39、ecord the differential mass to thenearest 0.1 mg. The solution mass will be read as a minus value on the balance.5. Clean the weighing buret with water, rinse it with acetone and blow-dry with a stream of nitrogen inpreparation for the next addition.6. Repeat Steps 2 to 5, weighing out and transferr
40、ing into the same flask 10 mL of the 1-mg/g palladiumstandard.7. Repeat Steps 2 to 5, weighing out and transferring into the same flask, 5 mL of the 1-mg/g goldstandard.8. Rinse the neck of the 100-mL volumetric flask with a little water, then add 20 mL of 1:1 sulfuric acidfrom a repeater pipet and
41、swirl.9. Add 20 mL of 1:1 HCl from a repeater pipet, rinse with water and swirl. Stopper the flask and set it aside until the samples are also ready for the internal standard addition. It isimperative that this addition be made simultaneously and with the same pipet.10. Add 5 mL of 1000-g/mL scandiu
42、m standard solution (see NOTE) as an internal standard using theRainin pipetter.11. Rinse the neck of the flask with water, fill to the mark and thoroughly mix. Store the ReferenceStandard in the dark until needed.12. See CALCULATIONS to determine the exact concentrations of palladium, gold and pota
43、ssium in theReference Standard.6 of 10916-93Sample Preparation of Whole Pill Catalyst1. Obtain and grind a representative sample of whole pill catalyst utilizing UOP Method 918.2. Shake the ground sample randomly by hand for 5 minutes to avoid errors caused by stratification dueto settling of the gr
44、ound sample in the bottle, then proceed immediately with Step 3. Once this step is complete, the homogenous powder must not be agitated until after the sample is taken.3. On a top loading balance, weigh out approximately 10-15 g of a thoroughly homogenized, powderedsample into the bottom of a petri
45、dish and gently tap it so as to create a thin layer of sample. Partiallycover the sample with the top of the petri dish and allow to air-equilibrate overnight with the ambientlaboratory air. Due to the hygroscopic properties of silica catalyst samples, an initial air equilibration of the sample prio
46、r toanalysis will result in improved precision.4. Scoop approximately 2.0-2.1 g of the ground air-equilibrated catalyst into a weighing scoop.5. Tare the weighing scoop with sample on the analytical balance to read zero.6. Transfer the catalyst sample carefully, to avoid dust loss, into the bottom o
47、f a 250-mL Teflon beaker.7. Place the empty weighing scoop onto the analytical balance and record the differential mass to thenearest 0.1 mg. The sample mass will be read as a minus value on the balance.8. Obtain duplicate LOIs of the air equilibrated sample according to UOP Method 909. Samples for
48、LOI must be taken at the same time the sample is weighed for the potassium, palladium andgold determination. The two LOIs are to be calculated to three significant figures and the results must agree within 5% relativestandard deviation or the analysis, beginning with Step 4, must be repeated. The pa
49、lladium will be in the from of PdO at 700C, introducing an insignificant positive analytical error of0.0007%.9. Place a Teflon enclosed, magnetic stirring bar into each Teflon beaker and cover with a quartz watchglass. The ribbed quartz watch glass was designed to allow SiF4gases to freely escape while preventing sprayand spatter losses during digestion. Unlike the tight cover Teflon watch glasses, sample digestion can alsobe observed. Due to HF attack on the quartz watch glass, reducing its thickness, eventual replacementafter 10 or more uses is necessary. Alter
