1、Standard Method of Test for Determination of Heavy Metal Content of Glass Beads Using X-Ray Fluorescence (XRF) AASHTO Designation: TP 106-13 (2015)1American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4c TP 106-1 AASHTO
2、 Standard Method of Test for Determination of Heavy Metal Content of Glass Beads Using X-Ray Fluorescence (XRF) AASHTO Designation: TP 106-13 (2015)11. SCOPE 1.1. This test method covers the determination of the total heavy metal content of glass beads using X-ray fluorescence (XRF). Heavy metals in
3、clude lead, antimony, and arsenic. 1.2. The values stated in SI units are to be regarded as the standard. 1.3. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety
4、and health practices and determine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: M 247, Glass Beads Used in Pavement Markings 3. SUMMARY OF TEST METHOD 3.1. This test method is used to determine the total concentration of heavy metals using X
5、RF testing. Testing may be performed with a Field Portable XRF (FP-XRF) or a laboratory XRF. 3.2. For an FP-XRF, the glass beads to be tested are placed in a loose state in a sample cup. 3.3. For a laboratory model XRF, the glass beads can be tested either in a loose state in a sample cup using a he
6、lium flush or as a pressed pellet. Note 1If using a laboratory model XRF, testing the glass beads in a loose state using a helium flush is the preferred method. 4. SIGNIFICANCE AND USE 4.1. This method is designed to identify the presence and concentration of heavy metals in samples of glass beads.
7、The method determines the total concentration and may be used to determine compliance with total concentration limits in M 247. 5. APPARATUS 5.1. XRF SpectrometerEither a field portable or a laboratory model XRF spectrometer may be used. If a laboratory model XRF spectrometer is used, it must be cap
8、able of operating with the analysis chamber under vacuum or flushed by helium (see Note 1). 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4c TP 106-2 AASHTO 5.2. Sample CupIf the test includes using
9、 an FP-XRF or with helium flush in a laboratory model XRF, use a thin-walled container to hold the loose glass beads. Sample cup includes a collar and cap. 5.3. Pressed Pellet PressIf the test includes using a vacuum in a laboratory model XRF, use a pressed pellet press to prepare the pressed pellet
10、 for testing. 5.4. Mixer MillIf the test includes using a vacuum in a laboratory model XRF, use a mixer mill to pulverize and blend the glass bead sample with the binding agent to prepare the pressed pellet for testing. 6. MATERIALS 6.1. For loose samples prepared in samples of beads tested in a sam
11、ple cup, polypropylene film, filter paper, and polyester fiber stuffing are needed. 6.1.1. FilmPolypropylene film. 6.1.2. Filter PaperFilter paper disk to fit over the sample. 6.1.3. Fiber StuffingPolyester fiber stuffing such as used for aquarium filter or pillow filling. 6.2. For pressed pellets,
12、a binder is required to form the glass beads into a pellet. 6.2.1. BinderLow absorption wax or cellulose binding agent. 6.2.2. Aluminum CupsUsed as backing for the pressed pellet sample. 7. SAMPLING AND SAMPLE PREPARATION 7.1. SamplingTake a representative sample of the glass beads. Store the sample
13、 in a container until ready for the test. 7.2. Sample Preparation of Loose Glass Beads in Sample CupIf the sample is to be tested using an FP-XRF or a laboratory model XRF with helium flush, the glass beads are tested in a sample cup. Use the following steps to prepare the sample: 7.2.1. Place polyp
14、ropylene film on top of an XRF sample cup. The film goes on the end of the cup with the indented ring. 7.2.2. Secure the film with the collar. The flange inside the collar faces down and snaps into the indented ring of the cup. Inspect the installed film window for continuity and smooth, taut appear
15、ance. 7.2.3. Place the sample cup on a flat surface with the film window-side down. Fill the cup with at least 5 g of glass beads. Place the beads in an even layer and lightly tamp into place. 7.2.4. Place a filter paper disk on the sample after tamping, then fill the cup with polyester fiber stuffi
16、ng. Put the cap on the cup. 7.3. Sample Preparation of Pressed PelletIf the sample is to be tested using a laboratory model XRF with a vacuum chamber, the glass beads are tested as a pressed pellet. Use the following steps to prepare the sample: 2015 by the American Association of State Highway and
17、Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4c TP 106-3 AASHTO 7.3.1. Combine 6.000 g of glass beads and 1.000 g of binding agent. 7.3.2. Using a mixer mill, pulverize and blend the glass beads and binding agent into a homogeneous sample for pressing
18、. Note 2For large beads, mill for 710 min. For small beads, mill for 57 min, depending on the type of mixer mill used. 7.3.3. Place an aluminum cup with tapered walls into the bottom of the press die chamber. 7.3.4. Add the homogeneous sample to press pressing. Follow the manufacturer procedures for
19、 the operation of the press. 7.3.5. Apply 25 tons of pressure for 4 min and use a 1-min release. 8. CALIBRATION AND STANDARDIZATION 8.1. XRF SpectrometerCalibrate or standardize the XRF spectrometer according to the manufacturers recommendations. 9. PROCEDURE 9.1. FP-XRFPlace the sample cup on a sta
20、ble surface. Direct the FP-XRF at the sample cup and run according to the manufacturers recommendations using the standard soil analysis mode. Record the concentration of lead, antimony, and arsenic. 9.2. Laboratory Model XRF with Helium FlushPlace the sample cup in the XRF. Run according to the man
21、ufacturers recommendations under helium gas conditions using a standard-less software program. Record the concentration of lead, antimony, and arsenic. 9.3. Laboratory Model XRF with VacuumPlace the pressed pellet in the XRF. Run according to the manufacturers recommendations under vacuum conditions
22、 using a standard-less software program. Record the concentration of lead, antimony, and arsenic. 10. INTERPRETATION OF RESULTS 10.1. The XRF reports the elements detected in the sample and elements that are below the detection limit. For an element to be detected by your analyzer in a given sample,
23、 the measured concentration of the sample must be at least three times the standard deviation of the measurement. This detection limit will depend on the composition of the sample. The measurement precision for each element displayed appears to the right of the measured concentration, under the head
24、ing “”. The precision of each measurement is two times the standard deviation (). An element is classified as “detected” if the measured concentration (in ppm) is at least 1.5 times the precision. Detected elements are displayed in ppm, followed by the measurement precision. Nondetected elements are
25、 shown as the detection limit (LOD) for that sample. The detection limit for a given element varies depending on the other elements in the matrix. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4c TP
26、 106-4 AASHTO 11. REPORT 11.1. Report the following information: 11.1.1. Sample identification; 11.1.2. Manufacturer; 11.1.3. Batch or lot number (if applicable); 11.1.4. Location sampled; and 11.1.5. Concentration of lead, antimony, and arsenic (ppm). 12. PRECISION AND BIAS 12.1. PrecisionThe resea
27、rch required to develop precision estimates has not been conducted. 12.2. BiasThe research required to establish the bias has not been conducted. 13. KEYWORDS 13.1. Glass beads; heavy metal; X-ray fluorescence; XRF. 1This provisional standard was first published in 2013. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.
