This method is included in NEMI for informational purposes as it is approved by EPA for regulatory use. Detailed information on this method is not currently. eropoly acid. This is reduced to silicomolybdenum blue that is determined pho- tometrically. The method is analogous to APHA SiO2 D+E, ASTM D, . Find the most up-to-date version of ASTM D at Engineering
|Published (Last):||9 October 2009|
|PDF File Size:||2.46 Mb|
|ePub File Size:||12.19 Mb|
|Price:||Free* [*Free Regsitration Required]|
ASTM D859 – 16
Calibration and Standardization Last previous edition approved in as D — For measurements at nm, plot absorbance versus milligrams SiO2 per litre. This can be compensated for by preparing standards in a matrix similar to that asgm samples or by using a standard additions technique.
The CVS is a solution of the method analyte of known concentration mid-calibration range used to fortify reagent water.
The MS should be prepared in accordance with Guide D Mix well and allow to stand for 10 min. Active view current version of standard. Measurements may be made at nm with a spectrophotometer, or to nm with a? Those forms of silica that are molybdate-reactive include dissolved simple silicates, monomeric silica and silicic acid, and an undetermined fraction of polymeric silica.
For measurements made at nm, silica concentration may be read directly in milligrams SiO2 per litre from the calibration curve prepared in NOTE 1—For many natural waters, a measurement of molybdatereactive silica by this test method provides a close approximation of total silica, and, in practice, the colorimetric method is frequently substituted for other more time-consuming techniques.
For seawater or brines, this test method is applicable only if matched matrix standards or standard addition techniques are employed. Silicon is the most abundant r859 in igneous rocks and is the characteristic element of all important rocks except the carbonates. Under the allowances made in 1. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
The analyte recoveries for the LCS should fall within the control limits of x 6 3S, where x is the IDP amount and S is the standard deviation of the mean recovery established from In contrast, silica may be added as a treatment chemical in some systems, for example, in corrosion control. When working with low concentrations of silica, a batch of ammonium molybdate known to produce reasonable blanks, linearity, ashm reproducibility should be set aside for this purpose.
Those forms astk silica that are molybdate-reactive include dissolved simple silicates, monomeric silica and silicic acid, and an undetermined fraction of polymeric silica.
Since the aetm includes an evaporation step, the applicable concentration range depends upon the volume of sample used in the determination. Prepare a blank using a Due to the complexity of silica chemistry, the form of silica measured is de? It may be applied to natural waters and wastewaters following? In solution it can exist as silicic acid or silicate ion, depending upon pH.
Under certain conditions, silica forms troublesome silica and silicate scales, particularly on high-pressure steam turbine blades.
Spike a portion of a water or other sample from each batch with the method analytes at the level of the IDP solution. Reagents and Materials NOTE 3—Store all reagents to be used in this test method in polyethylene or other suitable plastic bottles. For seawater or brines, this test method is applicable only if matched matrix standards or standard addition techniques are employed.
Link to Active This link will always route to the current Active version of the standard. For standards in the 0. Historical Version s ast view previous versions of standard Translated Version s: Unless otherwise indicated, it is intended that all reagents shall conform to the speci?
Quality Control QC It may be applied to natural waters and wastewaters following filtration or dilution, or both. It may be monomeric or polymeric. This test method is useful for concentrations as low as 20? The collecting apparatus and storage containers for the reagent water must be polyethylene or other suitable plastic.
Spectrophotometers shall conform to Practice E If the value still falls outside acceptable limits, a new calibration curve is required that must be con? Historical Version s – view previous versions of standard. A blank should also be run with each sample batch maximum of 20 samples to check for sample or system contamination. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
It is the responsibility of the user of asstm standard to aatm appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
ASTM D 水中硅测定的标准方法_百度文库
Refer to Appendix X1 for historical information. After dissolving, add the solution to mL of a solution containing 30 g d895 sodium hydrogen sul? Current edition approved Feb. It is found as the oxide in crystalline forms, as in quartz; combined with other oxides and metals in a variety of silicates; and in amorphous 1 This test method is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D It is particularly applicable to treated industrial waters.
Precision and Bias 5