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4.10 Watchglass, appropriate diameter to cover beaker or Erlenmeyer <br /> flask. <br /> 4.11 Magnetic stirrer. <br /> 5.0 REAGENTS <br /> 5.1 Reagent grade chemicals shall be used in all tests. Unless <br /> otherwise indicated, it is intended that all reagents shall conform to the <br /> specifications of the Committee on Analytical Reagents of the American Chemical <br /> Society, where such specifications are available. Other grades may be used, <br /> provided it is first ascertained that the reagent is of sufficiently high purity <br /> to permit its use without lessening the accuracy of the determination. <br /> 5.2 Reagent Water. Reagent water is defined as water in which an <br /> interferant is not observed at or above the method's detection limit of the <br /> analyte(s) of interest. For nonvolatile extractions, ASTM Type II water or <br /> equivalent meets the definition of reagent water. For volatile extractions, it <br /> is recommended that reagent water be generated by any of the following methods. <br /> Reagent water should be monitored periodically for impurities . <br /> 5.2.1 Reagent water for volatile extractions may be generated <br /> by passing tap water through a carbon filter bed containing about 500 <br /> grams of activated carbon (Calgon Corp. , Filtrasorb-300 or equivalent) . <br /> 5.2.2 A water purification system (Millipore Super-O or <br /> equivalent) may also be used to generate reagent water for volatile <br /> extractions. <br /> 5.2.3 Reagent water for volatile extractions may also be <br /> prepared by boiling water for 15 minutes. Subsequently, while maintaining <br /> the water temperature at 90 ± 5 degrees C, bubble a contaminant-free inert <br /> gas (e.4. nitrogen) through the water for 1 hour. While still hot, <br /> transfer the water to a narrow mouth screw-cap bottle under zero-headspace <br /> and seal with a Teflon-lined septum and cap. <br /> 5.3 Hydrochloric acid (1N) , HC1 , made from ACS reagent grade. <br /> 5.4 Nitric acid (1N) , HNO3, made from ACS reagent grade. <br /> 5.5 Sodium hydroxide (1N) , NaOH, made from ACS reagent grade. <br /> 5.6 Glacial acetic acid, CH3CH,OOH, ACS reagent grade. <br /> 5.7 Extraction fluid. <br /> 5.7.1 Extraction fluid # 1 : Add 5.7 mL glacial CH3CH200H to <br /> 500 mL of reagent water (See Section 5.2) , add 64.3 mL of 1N NaOH, and <br /> dilute to a volume of 1 liter. When correctly prepared, the pH of this <br /> fluid will be 4.93 + 0.05. <br /> CD-ROM 1311- 5 Revision 0 <br /> July 1992 <br />