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3、d. Nonconfidential 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 610.83
4、2.9585 PHONE. Trace Chloride, Fluoride, and Bromide in Liquid Organics by Combustion Ion Chromatography (CIC) UOP Method 991-13 Scope This method is for determining trace concentrations of chloride, fluoride, and bromide in liquid organics by Combustion Ion Chromatography (CIC). This method has a lo
5、wer limit of quantitation of 0.1 mg/kg (mass-ppm) for fluoride and chloride, and 0.2 mg/kg for bromide. References Instruction Manual for Automatic Quick Furnace, Model AQF-2100H, www.cosa- UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method A reproducible volume of
6、 sample is injected into a quartz boat. The boat is introduced into a multi-position horizontal furnace under controlled temperature and moisture. The sample is then combusted in a pyrohydrolytic, oxygen enriched environment. The halogens in the sample are converted to hydrogen halides and halogen g
7、as. These gases are then absorbed into an aqueous solution of constant volume. An aliquot of the solution is injected into an ion chromatograph (IC) where chloride, fluoride, and bromide are separated by anion exchange and measured by a conductivity detector with ion suppression. External standards
8、are used for quantitation. Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Balance, semi-micro, capacity 220 g, readable to 0.00001 g at 81 g Chromatographic column, IonPac AS11-HC Analytical, 250-mm length by 4-mm
9、ID, Dionex, Thermo Fisher, Cat. No. 052960 Combustion system, equipped with AQF-2100H furnace (HF-210 horizontal furnace), GA-210 gas adsorption unit, ABC-210 automatic boat controller, ASC-250L liquid autosampler, and AQF Software, COSA Instrument Corp. Newer models from the same manufacturer are a
10、lso suitable. Deionized water system, Nanopure Water Purification System with Total Organic Carbon Analyzer, Thermo Fisher, VWR Cat. No. 47729-610 2 of 14 991-13 Dry block heater, digital, 2 block capacity, 120V, 50/60Hz, 210W, VWR, Cat. No. 12621-088, and heating blocks with 15- and 28-mm diameter
11、vial wells, Cat. Nos. 12621-126 and -138, respectively Flask, volumetric, 1-L, borosilicate glass, Class A, VWR, Cat No. 89090-280 Ion chromatograph, equipped with a pump, injection valve/autosampler, eluent generator, continuously regenerated trap column, suppressor, conductivity detector, computer
12、, and Chromeleon software, Dionex, Thermo Fisher, Model ICS-2100 Muffle furnace, capable of operation at 800C, Barnstead/Thermolyne compact benchtop muffle furnace, Thermo Scientific, VWR Cat. No. 30631-230 Pipettor, Eppendorf Reference single-channel, variable volume, 100-1000 mL, VWR, Cat. No. 535
13、11-582 Refrigerator, laboratory, explosion proof or flammable storage, Fisher Scientific, Cat. No. 97-950 Regulator, argon, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tri-Gas, Model 3122-590 Regulator, oxygen, two-stage, high purity, delivery pressure range 30-7
14、00 kPa (4-100 psi), cleaned for oxygen service, Matheson Tri-Gas, Model 3810-540 Ultrasonic bath, Electron Microscopy Sciences Model 2510-M, VWR, Cat. No. 100501-412 Vortex mixer, digital, 120V, 50/60Hz, 75W, VWR, Cat. No. 14005-824 Reagents and Materials References to catalog numbers and suppliers
15、are included as a convenience to the method user. Other suppliers may be used. References to water mean deionized and distilled water that is subsequently treated to produce ionically pure, 18.2 megaohm-cm, organic-free (99.9%, VWR, Cat. No. BJ010 Adsorption tube, 10-mL, COSA Instrument Corp., Cat.
16、No. MC25000 (replacement) Argon, 99.999% pure Ball joint with U-shaped tube, COSA Instrument Corp., Cat. No. MC28017 (replacement) 4-Bromoacetanilide, 98% pure, Sigma-Aldrich, Cat No. 161659 4-Fluorobenzoic acid, 99+% pure, Sigma-Aldrich, Cat. No. 418846 Gloves, disposable, nitrile, VWR, Cat. No. 40
17、101, or cotton, VWR, Cat. No. 32935-460 Jars, 4-oz, wide mouth, with TeflonTM-lined closures, for sample preparation, VWR, Cat. No. 89044-078 Methanol, B then draw 80 L of sample/standard into the syringe. 4. Place syringe on balance and weigh syringe. Record the weight to nearest 0.00001 g. For a s
18、ample that must be heated, weigh the heated syringe with sample and immediately dispense the contents. 5. Enter the weight in the chromatography software under the weight column for the associated sample/standard. 6. Dispense weighed liquid into the waste bottle of the autosampler. 7. Rinse syringe
19、with 3 syringe volumes of toluene. a. Repeat Steps 2-6 for all samples and standards. b. Proceed to Step 8 when all standards and samples have been weighed. 8. Return the clean syringe to the autosampler and proceed to Step 3 of Liquid Injection for liquid samples or Step 5 of Heated Sample Injectio
20、n for viscous or waxy samples to start the analysis. Analysis of Standard Calibration Solutions 1. Fill sample vials with all four Standard Calibration Solutions and load them onto the liquid autosampler. 2. Inject 80 L of Standard Calibration Solution 1 into the quartz boat of the automatic boat co
21、ntroller (ABC) and start the combustion and IC sequences. Identify and integrate each peak for the calibration standards. Identification can be aided by comparing to the typical standard chromatogram (see Figure). Individual standards may need to be prepared to identify retention times. Cumulative m
22、ultiple injections in the absorption solution increase the effective concentration of the analytes of interest. For low concentrations, from 0.1-10 mg/kg, it is required to run 3 cumulative injections to increase the response of fluoride, chloride, and bromide. For concentrations from 10-1000 mg/kg,
23、 a single injection is sufficient. 3. Calculate the response factor for each analyte using the chromatography software or Equation 3 in Calculations. 4. Repeat Steps 3 and 4 with Standard Calibration Solutions 2, 3, and 4. Analysis of Blank Blank runs may be needed to check for interference or carry
24、over from a previous analysis. 1. Start the combustion and IC process with an empty sample boat under the same burn program 10 of 14 991-13 as the standards and/or samples. 2. Identify and integrate peak areas of interest. 3. If background peaks are higher than the lowest standard, run the default b
25、oat prebake method five times and re-analyze another empty sample boat blank injection. If background is still high, remove the old quartz boat. Replace with a new quartz boat and quartz wool. Run five boat prebakes and then return to Step 1. Sample Analysis There are two types of injections listed
26、below. Use Liquid Injection for samples that do not need to be heated prior to analysis. Use Heated Sample Injection for samples that are viscous or waxy at room temperature. Samples that are still viscous after heating must be diluted with toluene. Liquid Injection 1. Proceed to Step 3 if the sampl
27、e is not to be diluted. If the sample is to be diluted, weigh approximately 1 g of the sample into a 4-dram vial and record the weight to the nearest 0.00001 g. 2. Add approximately 9 g of toluene to the solution and record the total diluted weight to the nearest 0.0001 g. Cap the vial and vortex th
28、e sample solution for approximately 30 seconds so that the sample is thoroughly mixed. 3. Fill an autosampler vial with the sample or the diluted sample. 4. Inject 80 L of the sample into the quartz boat and start the combustion and IC sequences. If accumulated injections were run on the standards,
29、the exact same number of accumulated injections must be run on the samples, for example if three 80-L injections were made for the calibration standards, then three 80-L injections are required for the samples. 5. Identify each analyte by retention time (see Figure). Integrate the analyte peaks of i
30、nterest to calculate the area response. 6. If the areas obtained for any of the analytes are above the highest standard, prepare quantitative serial dilution(s) of the sample. This is done by diluting the sample or sample solution in toluene on a mass/mass basis until the resulting chromatographic a
31、nalyte peak areas fit within the calibration standards. Record the weights of each serial dilution to the nearest 0.00001 g. Label as Serial Diluted Sample (X). Repeat Steps 3 and 4 of Liquid Injection for the serially diluted sample(s). Heated Sample Injection 1. Turn on the digital block heater. T
32、he heater should not exceed 70-80C. 2. Place sample vial in heater block until sample is liquefied. 3. Remove the sample vial from heater block, uncap, and pour an aliquot into an autosampler vial. 4. Place the autosampler vial into the vial heater to keep warm. 5. Slide the autosampler away from th
33、e injection port of the automatic boat controller and inject 80 L of sample directly into the quartz boat. Start the combustion and IC sequences. If accumulated injections were run on the standards, the exact same number of accumulated injections must be run on the samples, for example, if three 80-
34、L injections were made for the calibration standards, then three 80-L injections are required for the samples. Place the syringe on the heater block to warm up to the same temperature as the sample. This will 11 of 14 991-13 prevent the sample from solidifying in the syringe when trying to inject in
35、to the quartz boat in the automatic boat controller. 6. Identify each analyte by retention time (see Figure). Integrate the analyte peaks of interest to calculate the area response. 7. If the areas obtained for any of the analytes are above the highest standard, prepare quantitative serial dilution(
36、s) of the sample. This is done by diluting the samples in toluene on a mass/mass basis until the resulting chromatographic analyte peak areas fit within the calibration standards. Record the weights of each serial dilution to the nearest 0.00001 g. Label as Serial Diluted Heated Sample (X). The vial
37、s may need to be heated to ensure the sample is completely dissolved. Weigh the syringe as described in Density Correction, and repeat Steps 4 and 5 in Heated Sample Injection for the serially diluted and heated samples. Calculations All calculations are performed by the instrument software and resu
38、lts are displayed and printed in mass-ppm (mg/kg). If the sample and standard vary in density, the masses of an 80-L liquid injection of the samples and standards are entered during sample data entry to compensate for the difference. The calculations below are included for information and for single
39、 point manual calculation, if desired. Calculate the response factor for each analyte in the standard calibration solutions to three significant figures using Equation 4. NLM = (4) where: L = concentration of each analyte in each level of Standard Calibration Solution, mg/kg, as defined in Equation
40、3 M = response factor for each analyte N = analyte response area Calculate the dilution factor for each sample to three significant figures using Equation 5. Proceed to Equation 6 if the sample was not diluted. The dilution factor = 1 if no dilution was made. R = QP (5) where: P = total mass of samp
41、le and diluent (Liquid Injection, Step 2), g Q = total mass of sample weighed (Liquid Injection, Step 1), g R = dilution factor for diluted sample solution Calculate the ratio of standard weight injected to sample weight injected to three significant figures using Equation 6. U = TS (6) where: S = w
42、eight of standard injected T = weight of sample injected U = ratio of standard weight injected to sample weight injected Calculate each analyte concentration in the original sample to the nearest 0.1 mg/kg, not to exceed two significant figures, using Equation 7. 12 of 14 991-13 Concentration of ana
43、lyte in sample or sample solution, mg/kg = ( ) WVMRU (7) where: M = response factor for each analyte, from Equation 4 R = dilution factor for diluted sample solution, from Equation 5 U = ratio of standard weight injected to sample weight injected, from Equation 6 V = final diluted sample mass (if se
44、rial dilution is needed), g W = mass of IC sample stock solution aliquot (if serial dilution is needed), g If no serial dilution is required, V/W = 1 Precision Precision statements were determined using UOP Method 999, “Precision Statements in UOP Methods.” Repeatability and Site Precision A nested
45、design was carried out for determining halogens in liquid organics by two analysts, with each analyst performing analyses on four samples on two separate days, performing two analyses each day for a total of 32 analyses. Using a stepwise analysis of variance procedure, the within-day and within-lab
46、estimated standard deviations (esd) were calculated at the concentration means listed in Table 4. Two analyses performed in one laboratory by the same analyst on the same day should not differ by more than the repeatability allowable differences shown in Table 4 with 95% confidence. Two analyses per
47、formed in one laboratory by different analysts on different days should not differ by more than the site precision allowable differences shown in Table 4 with 95% confidence. Table 4 Repeatability and Site Precision, mg/kg Repeatability Site Precision Component Mean Within- Day esd Allowable Differe
48、nce Within- Lab esd Allowable Difference Chloride 0.1 0.01 0.1 0.01 0.1 Chloride 1.4 0.08 0.3 0.09 0.3 Chloride 10.7 0.25 1.0 0.35 1.4 Chloride 16.7 0.34 1.4 0.36 1.4 Fluoride 0.1 0.01 0.1 0.01 0.1 Fluoride 0.6 0.11 0.4 0.21 0.9 Fluoride 8.8 0.12 0.5 0.41 1.9 Fluoride 13.8 0.49 1.9 0.49 2.5 Bromide
49、0.1 0.02 0.1 0.02 0.1 Bromide 1.3 0.14 0.6 0.14 0.6 Bromide 12.2 0.32 1.3 0.38 1.5 Bromide 17.8 0.36 1.4 0.52 2.0 The data in Table 4 represent short-term estimates of the repeatability of the method. When the test is run routinely, use of a control standard and a control chart is recommended to generate an estimate of long-term repeatability. Reproducibility There is insufficient data to calculate the reproducibility of the test at this time. 13 of 14 991-13 Time for Analysis The elapsed time for the preparation and analysis of one sa
