UOP 1009-2015 Total Mercury in Solids.pdf

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. SAFETY DATA SHEETS (SDS) 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 2015 UOP LLC. All rights reserved. Nonconfidenti

3、al UOP Methods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. 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 610.832.9585 PHONE. To

4、tal Mercury in Solids UOP Method 1009-15 Scope This method is for determining total mercury in solid materials using a Nippon Instruments Corporation (NIC) MA-3000 Mercury Analyzer. The instrument uses a dual path detector to measure from the lower limit of 0.1 ng/g (mass-ppb) to an upper limit of 5

5、00 g/g (mass-ppm), when analyzing a 50 mg sample. This procedure can also be used for aqueous liquid samples and high boiling hydrocarbons (such as crude or shale oil) through the use of appropriate combustion programs. Volatile hydrocarbons (e.g. naphtha and BTX aromatics) should be analyzed by UOP

6、 Method 938. References UOP Method 938, “Total Mercury and Mercury Species in Liquid Hydrocarbons,” www.astm.org UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method The NIC Mercury Analyzer/Model MA-3000, consisting of an autosampler, a mercury atomizer and integrat

7、ed mercury detector, is specified for this method. The sample is decomposed by heating in oxygen and the mercury vapor in the gaseous products is trapped by the mercury collector as gold amalgam. The temperature of the mercury collector is kept at 210C to prevent the adsorption of non-mercury combus

8、tion products on the collector. After collection, the mercury is liberated by heating the collector to 700+C. The vaporized mercury is carried to a dual absorption cell (long and short path lengths) with a pure oxygen carrier gas and detected by the cold vapor atomic absorption technique. After intr

9、oducing the sample into boats and loading the autosampler rack, all operations from the sample decomposition process to the mercury detection and calculation are carried out automatically by the instrument. The instrument collects data from both cells, and the selection of High or Low range can be c

10、hanged by the operator after the sample analysis has completed. Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used, unless stated otherwise. Balance, readability 0.01-mg, Mettler-Toledo XA105 or equivalent. If a differe

11、nt balance is used, it should be one that will directly communicate with the MA3Win software. 2 of 10 1009-15 Cylinder, graduated, 500-ml, Class B, VWR, Cat. No. 89000-258 Desiccator, VWR, Cat. No. 25031-048 (Corning 3120-250), optional Flasks, volumetric, glass, Class A, 100- (several required), 50

12、0- and 1000-mL, Fisher Scientific, Cat. Nos. 10-210-8C, F and G, respectively Furnace, muffle, 120 V, 50/60 Hz, 1200C maximum, Fisher Scientific, Cat. No. 10-554-28, optional Gloves, thermal protection, VWR, Cat. No. 32885-407, optional Mercury analyzer, NIC, Model MA-3000 (no substitute), with the

13、following accessories: Boats, ceramic, for MA-3000, NIC, Cat. No. S1106-6100-00 Sample heating tube MA-3, NIC, Cat. No. S1106-0620-00. Tubes with catalyst for Appendix K should be used with high halogen samples. Sample boat fixture (for measurement), NIC, Cat. No. N-1106-901-400 Mortar and Pestle, A

14、gate, Fisher Scientific, Cat. No. 12-950B Pipet, digital, variable volume 20-200 L, Fisher Scientific, Cat. No. 21-377-289 (required for the analysis of heavy hydrocarbon and calibration samples) Pipets, volumetric, Class A, 1-, 2-, 5-, and 10-mL, Fisher Scientific, Cat. Nos. 13-660A, B, E, and F, r

15、espectively Pipet filler, Fisher Scientific, Cat. No. 13-681-51 Refrigerator, explosion proof or flammable storage Regulator, 2-stage Stainless Steel, CGA 540, Matheson Cat. No. 3810-540 Sample containers, glass or Teflon bottles, acid cleaned, see Procedure Tongs, crucible, VWR, Cat. No. 82027-372,

16、 for muffle furnace use Tweezers, flat, round point, Baxter Scientific, Cat. No. E1200-9 Wash bottle, Nalgene, LDPE, 500-mL, Fisher Scientific, Cat. No. 03-409-17F (used for nitric acid washing of all glassware) Wash bottle, Nalgene, Right to Know Safety, 500-mL, for acetone, Fisher Scientific, Cat.

17、 No. 03-409-11A Wash bottle, Nalgene, Right to Know Safety, 500-mL, for water, Fisher Scientific, Cat. No. 03-409-11E Reagents and Materials References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used, unless stated otherwise. References

18、to water mean deionized or distilled water. Acetone, Fisher Scientific, Cat. No. A18-4 Aluminum Foil, local supply, optional L-Cysteine, 99% purity, Pfaltz and Bauer, Cat. No. C33800 Mercuric chloride, mercury (II) chloride, 99.999% purity, Sigma-Aldrich, Cat. No. 20-377-7 (Note: Toxic material, rev

19、iew SDS before handling and wear appropriate personal protective equipment) 3 of 10 1009-15 Nitric acid, concentrated, Trace Metal Grade, Fisher Scientific, Cat. No. A509-212 Nitric Acid, 1:1. Combine 200 mL of concentrated nitric acid with 200 mL of water in a plastic wash bottle, swirl to mix, and

20、 use freshly prepared while still warm. Nitrogen, or oil-free clean air, for blow drying glassware Oxygen, UHP, Airgas Cat. No. OX UHP200 Pipet tips, disposable, Fisher Scientific, Cat. No. 21-377-45 QC standard, a certified Hg standard should be obtained for use as a Quality Control (QC) standard.

21、An example is NIST 1632d (Trace Elements in Coal) at 0.0928 mg/kg Hg. Transfer pipets, disposable, Fisher Scientific Cat. No. 13-711-9AM Water, deionized or distilled. Certified low Hg reagent water can be purchased from O2SI, Cat. No. 190007-16 Weighing paper, Fisher Scientific, Cat. No. 09-898-12A

22、 Procedure The analyst is expected to be familiar with general laboratory practices and the equipment being used. Portions of these procedures are specific to the specified apparatus. Sampling Samples should be collected in a manner that assures representative sampling. Elemental mercury and organic

23、-mercury species are unstable and will react with the walls of the sample containers. Do not collect samples in metal containers. Mercury present can adsorb on the metal. Liquid samples must be collected in previously acid cleaned glass containers and then analyzed as soon as possible. Instrument Se

24、t Up 1. Set up the instrument according to the manufacturers instructions. 2. Turn on the power to the instrument and start the MA3Win control software on the PC. The instrument is normally turned off overnight and when not in use. Standard operating conditions are shown in Table 1. 3. Allow the ins

25、trument to stabilize. The instrument software will display a timer to show remaining stabilization time. Table 1 Operating Conditions Idle Temperature of sample heating furnace 150C Temperature of decomposition furnace element (front zone) 560C Temperature of decomposition furnace element (back zone

26、) 300C Pre-heating temperature of mercury collector 210C Mercury collector desorb temperature 700+C Detector Temperature 150C Carrier gas Oxygen, min. purity 99% Carrier gas pressure 50 kPa Combustion (Decomposition) flow rate 0.4 L/min Measuring system flow rate (AAS) 0.5 L/min Analysis time (depen

27、dent on heating method) 10 min 4 of 10 1009-15 4. Perform a system leak check from the MA3Win software menu (Run Leak Check). Once flow stabilizes at 0.4 0.01 L/min, click “START”. The flow should decrease to a level at or below 0.02 L/min within 1 minute. If this does not occur, then the instrument

28、 should be turned off and allowed to cool before checking the instrument for loose joints or damaged tubes. The instrument must pass the leak test before it can be calibrated or used to analyze samples. 5. In addition to the factory pre-defined decomposition methods, a new method needs to be created

29、 for catalysts, adsorbents and heavy hydrocarbons as shown in Table 2. Table 2 Catalyst Method Conditions Atomize 1 Heat Temperature 150C Atomize 1 Heat Time 60 s Atomize 1 Start Duty 5% Atomize 1 Max Duty 5% Atomize 1 Slope Time 60 s Atomize 2 Heat Temperature 350C Atomize 2 Heat Time 120 s Atomize

30、 2 Start Duty 30% Atomize 2 Max Duty 30% Atomize 2 Slope Time 0 s Atomize 3 Heat Temperature 850C Atomize 3 Heat Time 300 s Atomize 3 Start Duty 10% Atomize 3 Max Duty 100% Atomize 3 Slope Time 90 s Atomize Step 4 is not used Preparation of L-Cysteine Solution and Standards L-Cysteine Solution, Appr

31、oximately 100-mg/L 1. Weigh approximately 0.10 g of L-cysteine, to the nearest 0.1 mg, onto a weighing paper. 2. Transfer quantitatively with deionized water into a 1000-mL volumetric flask. Pipet 2 mL of concentrated nitric acid and dilute to the mark with deionized water. Cap and invert several ti

32、mes to mix thoroughly. L-cysteine prevents the deposition of mercury on the walls of the glassware. Mercury Standard, Approximately 100-mg/L Alternatively, the standard solutions may be prepared from commercially available 1000-mg/L solutions provided with a certificate of analysis. 1. Weigh approxi

33、mately 0.067 g of mercuric chloride, to the nearest 0.1 mg, onto a weighing paper. 2. Transfer quantitatively with the 100-mg/L L-cysteine solution into a 500-mL (0.5-L) volumetric flask. 3. Dilute to the mark with the 100-mg/mL L-cysteine solution. Cap and invert several times to mix thoroughly. 5

34、of 10 1009-15 4. Calculate the concentration of mercury (Hg) in the standard to three significant figures using Equation 1: Hg, mg/L = 5.0 M)739.0(103 (1) where: M =mass of mercuric chloride, g 0.5 =dilution volume, L 0.739 = molecular mass of mercury (200.6) divided by the molecular mass of mercuri

35、c chloride (271.5) 103 = factor to convert g to mg Mercury Standard, Approximately 10-mg/L 1. Pipet 10 mL of the 100-mg/L mercuric chloride standard into a 100-mL volumetric flask. 2. Dilute to volume with the 100-mg/L L-cysteine solution. Cap and invert several times to mix thoroughly. The actual c

36、oncentration of this standard will be one-tenth of the standard being diluted. Mercury Standard, Approximately 1-mg/L 1. Pipet 1 mL of the 100-mg/L mercury standard into a 100-mL volumetric flask. 2. Dilute to volume with the 100-mg/mL L-cysteine solution. Cap and invert several times to mix thoroug

37、hly. The actual concentration of this standard will be one-hundredth of the standard being diluted. Mercury Standard, Approximately 0.1-mg/L 1. Pipet 10 mL of the 1-mg/L mercury standard into a 100-mL volumetric flask. 2. Dilute to volume with the 100-mg/L L-cysteine solution. Cap and invert several

38、 times to mix thoroughly. The actual concentration of this standard will be one-tenth of the standard being diluted. Mercury Standard, Approximately 0.01-mg/L 1. Pipet 10 mL of the 0.1-mg/L mercury standard into a 100-mL volumetric flask. 2. Dilute to volume with the 100-mg/L L-cysteine solution. Ca

39、p and invert several times to mix thoroughly. The actual concentration of this standard will be one-tenth of the standard being diluted. Mercury Standard, Approximately 0.001-mg/L 3. Pipet 10 mL of the 0.01-mg/L mercury standard into a 100-mL volumetric flask. 4. Dilute to volume with the 100-mg/L L

40、-cysteine solution. Cap and invert several times to mix thoroughly. The actual concentration of this standard will be one-tenth of the standard being diluted. The mercury standard solutions should be stored in a cool dark place. The maximum shelf life of the solutions is as follows: 6 of 10 1009-15

41、100-mg/L L-cysteine solution - 6 months Mercury standard solutions with concentrations 0.1 mg/L and greater - 6 months Mercury standard solutions with concentrations less than 0.1 mg/L - 1 month Analysis of Solid Samples Inorganic solid samples, such as catalysts and adsorbents should be ground to a

42、 fine, homogeneous powder using a mortar and pestle. Agate mortar and pestle sets are recommended to minimize the loss of Hg and to prevent sample cross-contamination. Metal grinding vessels and mechanical grinders should not be used, due to the potential for loss of Hg during grinding. Analysis of

43、Liquid Hydrocarbons Samples that contain volatile material, e.g., gasoline, are analyzed using UOP Method 938. Less volatile hydrocarbons, e.g., kerosene, diesel, and heavier, can be analyzed using this procedure. When analyzing liquids, it is recommended that only 1 tray of sample boats should be l

44、oaded at a time. Preparation of Sample Boats Boats can be pretreated to remove Hg by cycling through the instrument using an analysis method with a decomposition step of at least 800C. The use of a separate muffle furnace is also acceptable. 1. Set the muffle furnace temperature at 750 50C. 2. Place

45、 sample boats to be used for the analysis in the muffle furnace. 3. Heat boats for at least 2 hours in the muffle furnace. 4. Cool in a dessicator before placing the boats on the sample trays in the instrument. Calibration It is recommended that the analyzer be calibrated regularly, either based on

46、the Control Chart of a QC reference or on a timed schedule during times when samples are being analyzed. The vaporized Hg passes through both cells, so the instrument calibration can include standards for both the Low and High range calibrations. To create each calibration curve, the measurement of

47、three mercury standards is recommended. Use Table 3 to select the appropriate range, standard solutions and injection volumes. For high level calibrations where standards above 10.0 mg/L are used, then calibrate for High range Hg only, up to a maximum of 25.0 g per measurement. The calibration slope

48、 must be between 0.7 and 1.3, otherwise the instrument will return a warning message. Table 3 Calibration Ranges and Standards Measuring Range Standard Solution, mg/L Standard Solution Injection Volume, L Low 0.001 0.01 0.10 50, 100 50, 100, 200 50, 90 7 of 10 1009-15 High 0.10 1.00 10.0 Higher stan

49、dards can be added up to a maximum of 25.0 g of Hg (250 L of 100 mg/L) 100, 200 50, 100, 200 50, 100, 200 1. Remove the sample tray from the rack inside the autosampler. If the boats were pretreated in the muffle furnace, place boats on the tray in each of the 10 positions. Tweezers must be used when handling the boats. Close the cover to the autosampler when not actively adding or removing trays. Place the sample tray on a clean surface, such as aluminum foi