A: The IR spectrum of a potassium bromide dispersion of it exhibits maxima at 3677 ± 2 cm–1, at 1018 ± 2 cm–1, and at 669 ± 2 cm–1.

B: Mix about 200 mg of anhydrous sodium carbonate with 2 g of anhydrous potassium carbonate, and melt in a platinum crucible. To the melt add 100 mg of the substance under test, and continue heating until fusion is complete. Cool, and transfer the fused mixture to a dish or beaker with the aid of about 50 mL of hot water. Add hydrochloric acid to the liquid until effervescence ceases, then add 10 mL more of the acid, and evaporate the mixture on a steam bath to dryness. Cool, add 20 mL of water, boil, and filter the mixture: [NOTE—Save the insoluble residue for use in Identification test C.] To 5 mL of the filtrate add 1 mL of 6 N ammonium hydroxide and 1 mL of ammonium chloride TS. Filter, if necessary, and add 1 mL of dibasic sodium phosphate TS to the filtrate: a white crystalline precipitate of magnesium ammonium phosphate is formed.

C: In a lead or platinum crucible and using a copper wire, mix about 100 mg of the insoluble residue as obtained in Identification test B with about 10 mg of sodium fluoride and a few drops of sulfuric acid to give a thin slurry. Cover the crucible with a thin transparent plate of plastic under which a drop of water is suspended, and warm gently. Within a short time, a white ring is rapidly formed around the drop of water.

Test stock solution— Weigh 10.0 g of Talc into a conical flask fitted with a reflux condenser, gradually add 50 mL of 0.5 N hydrochloric acid while stirring, and heat on a water bath for 30 minutes. Allow to cool. Transfer the mixture to a beaker, and allow the undissolved material to settle. Filter the supernatant into a 100-mL volumetric flask, retaining as much as possible of the insoluble material in the beaker. Wash the residue and the beaker with three 10-mL portions of hot water. Wash the filter with 15 mL of hot water, allow the filtrate to cool, and dilute with water to 100.0 mL.

Test solution— Transfer 2.5 mL of the Test stock solution to a 100-mL volumetric flask, add 50.0 mL of 0.5 N hydrochloric acid, and dilute with water to volume.

Standard iron stock solution— Transfer 863.4 mg of ferric ammonium sulfate to a 100-mL volumetric flask, dissolve in water, add 10 mL of 2 N sulfuric acid, and dilute with water to volume. Pipet 25 mL of this solution into a 100-mL volumetric flask, add 10 mL of 2 N sulfuric acid, dilute with water to volume, and mix. This solution contains the equivalent of 250 µg of iron per mL.

Standard iron solutions— Into four 100-mL volumetric flasks, each containing 50.0 mL of 0.5 N hydrochloric acid, transfer respectively 2.0, 2.5, 3.0, and 4.0 mL of the Standard iron stock solution, and dilute each flask with water to volume.

Procedure— Concomitantly determine the absorbance of the Test solution and the Standard iron solutions at the iron emission line of 248.3 nm with an atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering 851) equipped with an iron hollow-cathode lamp and an air–acetylene flame. Make any correction using a deuterium lamp: not more than 0.25% of iron is found.

Test solution— Use the Test stock solution, prepared as directed in the test for Limit of iron.

Lead standard stock solution— Dissolve 160 mg of lead nitrate in 100 mL water that contains 1 mL of nitric acid, and dilute with water to 1000 mL. Pipet 10 mL of this solution into a 100-mL volumetric flask, dilute with water to volume, and mix. This solution contains the equivalent of 10 µg of lead per mL.

Standard lead solutions— Into four identical 100-mL volumetric flasks, each containing 50.0 mL of 0.5 N hydrochloric acid transfer respectively 5.0, 7.5, 10.0, and 12.5 mL of Lead standard stock solution, and dilute with water to volume.

Procedure— Concomitantly determine the absorbance of the Test solution and the Standard lead solutions at the lead emission line of 217.0 nm with an atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering 851) equipped with a lead hollow-cathode lamp and an air–acetylene flame: not more than 0.001% of lead is found.

Cesium chloride solution— Dissolve 2.53 g of cesium chloride in 100 mL of water, and mix.

Lanthanum chloride solution— To 5.9 g of lanthanum oxide slowly add 10 mL of hydrochloric acid, and heat to boiling. Allow to cool, and dilute with water to 100 mL.

Test stock solution— [Caution—Perchlorates mixed with heavy metals are known to be explosive. Take proper precautions while performing this procedure. ] Weigh 500 mg of Talc in a 100-mL polytetrafluoroethylene dish, add 5 mL of hydrochloric acid, 5 mL of lead-free nitric acid, and 5 mL of perchloric acid. Stir gently, then add 35 mL of hydrofluoric acid, and evaporate slowly on a hot plate to moist dryness (until about 0.5 mL remains). To the residue, add 5 mL of hydrochloric acid, cover with a watch glass, heat to boiling, and allow to cool. Rinse the watch glass and the dish with water, and transfer into a 50-mL volumetric flask containing 5 mL of the Cesium chloride solution. Rinse the dish again with water, and dilute with water to volume.

Test solution— Transfer 5.0 mL of the Test stock solution to a 100-mL volumetric flask, add 10.0 mL of hydrochloric acid and 10 mL of Lanthanum chloride solution, and dilute with water to volume.

Calcium standard stock solution— Dissolve 3.67 g of calcium chloride dihydrate in diluted hydrochloric acid, and dilute with the same solvent to 1000 mL. Immediately before use, pipet 10 mL of this solution into a 100-mL volumetric flask, dilute with water to volume, and mix. This solution contains the equivalent of 100 µg of calcium per mL.

Standard calcium solutions— Into four identical 100-mL volumetric flasks, each containing 10.0 mL of hydrochloric acid and 10 mL of Lanthanum chloride solution, transfer respectively 1.0, 2.0, 3.0, and 4.0 mL of Calcium standard stock solution, and dilute each flask with water to volume.

Procedure— Concomitantly determine the absorbance of the Test solution and the Standard calcium solutions at the calcium emission line of 422.7 nm with an atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering 851) equipped with a calcium hollow-cathode lamp and a nitrous oxide–acetylene flame: not more than 0.9% of calcium is found.

Cesium chloride solution and Test stock solution— Proceed as directed in the test for Limit of calcium.

Test solution— Transfer 5.0 mL of the Test stock solution to a 100-mL volumetric flask, add 10 mL of the Cesium chloride solution and 10.0 mL of hydrochloric acid, and dilute with water to volume.

Aluminum standard stock solution— Dissolve 8.947 g of aluminum chloride in water, and dilute with water to 1000 mL. Immediately before use, pipet 10 mL of this solution into a 100-mL volumetric flask, dilute with water to volume, and mix. This solution contains the equivalent of 100 µg of aluminum per mL.

Standard aluminum solutions— Into four identical 100-mL volumetric flasks, each containing 10.0 mL of hydrochloric acid and 10 mL of Cesium chloride solution, transfer respectively 5.0, 10.0, 15.0, and 20.0 mL of Aluminum standard stock solution, and dilute with water to volume.

Procedure— Concomitantly determine the absorbance of the Test solution and the Standard aluminum solutions at the aluminum emission line of 309.3 nm with an atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering 851) equipped with an aluminum hollow-cathode lamp and a nitrous oxide–acetylene flame: not more than 2.0% of aluminum is found.

A: The IR absorption spectrum of a potassium bromide dispersion of it at the absorption band at 758 ± 1 cm–1, using scale expansion, may indicate the presence of tremolite or of chlorite. If the absorption band remains after ignition of the substance at 850 for at least 30 minutes, it indicates the presence of the tremolite. In the range 600 cm–1 to 650 cm–1 using scale expansion, any absorption band or shoulder may indicate the presence of serpentines.

B: X-ray diffraction 941 employing the following conditions: Cu K monochromatic 40 kV radiation, 24 mA to 30 mA; the incident slit is set at 1; the detection slit is set at 0.2; the goniometer speed is 1/10 2 per minute; the scanning range is 10 to 13 2 and 24 to 26 2; the sample is not oriented. Prepare a random sample, and place on the sample holder. Pack and smooth its surface with a polished glass microscope slide. Record the diffractograms: the presence of amphiboles is detected by a diffraction peak at 10.5 ± 0.1 2, and the presence of serpentines is detected by diffraction peaks at 24.3 ± 0.1 2 to 12.1 ± 0.1 2.

C: The presence of asbestos (see Optical Microscopy 776) is shown if there is a range of length to width ratios of 20:1 to 100:1, or higher for fibers longer than 5 µm; if there is a capability of splitting into very thin fibrils; and if there are two or more of the following four criteria: (1) parallel fibers occurring in bundles, (2) fiber bundles displaying frayed ends, (3) fibers in the form of thin needles, or (4) matted masses of individual fibers and/or fibers showing curvature.

Lanthanum chloride solution and Test stock solution— Prepare as directed in the test for Limit of calcium.

Test solution— Dilute 0.5 mL of Test stock solution with water to 100.0 mL. Transfer 4.0 mL of this solution to a 100-mL volumetric flask, add 10.0 mL of hydrochloric acid and 10 mL of Lanthanum chloride solution, and dilute with water to volume.

Magnesium standard stock solution— Dissolve 8.365 g of magnesium chloride in diluted hydrochloric acid, and dilute with the same solvent to 1000 mL. Pipet 5 mL of this solution into a 500-mL volumetric flask, dilute with water to volume, and mix. This solution contains the equivalent of 10 µg of magnesium per mL.

Standard magnesium solutions— Into four identical 100-mL volumetric flasks, each containing 10.0 mL of hydrochloric acid and 10 mL of Lanthanum chloride solution, transfer respectively 2.5, 3.0, 4.0, and 5.0 mL of Magnesium standard stock solution, and dilute with water to volume.

Procedure— Concomitantly determine the absorbance of the Test solution and the Standard magnesium solutions at the magnesium emission line of 285.2 nm with an atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering 851) equipped with a magnesium hollow-cathode lamp and an air–acetylene flame: between 17.0% to 19.5% of magnesium is found.

(Official January 1, 2007)