OMB Meeting Book_9-11-14

C. Chemicals and Solvents

( a ) Acetic acid .—Glacial, ACS. ( b ) Chloroform .—High-purity, HPLC grade. ( c ) Diethyl ether .—Anhydrous, HPLC grade. ( d ) Drierite (desiccant) .—Anhydrous calcium sulfate, 8 mesh. ( e ) Helium .—Zero grade or equivalent. ( f ) Hexane .—HPLC grade. ( g ) Hydrochloric acid .—Concentrated (36–38%), ACS. ( h ) Distilled or deionized laboratory water. ( i ) Methanol .—HPLC grade. ( j ) Myo-inositol .—USP reference standard, official lot; store desiccated. See standard label for purity. ( k ) Sodium acetate trihydrate or sodium acetate .—Anhydrous, ACS. ( l ) Sodium chloride. ( m ) Sodium hydroxide .—50% (w/w), low carbonate form. All solutions can be scaled up or down for convenience provided good laboratory practices are observed. Solutions can be stored at 2–30°C in tight, inert containers otherwise noted. ( a ) Myo-inositol stock standard solution (approximately 2000 mg/L).— Accurately weigh approximately 0.100 g myo- inositol and quantitatively transfer to a 50 mL volumetric flask. Dilute to volume with water. Mix well. Store refrigerated. Expiration: 3 months. ( b ) Myo-inositol intermediate standard solution (approximately 200 mg/L).— Dilute 10.0 mL stock standard to 100 mL with laboratory water and mix well. Discard after use. ( c ) Myo-inositol working standard solutions (approximately 4, 2, 1, 0.5, 0.2, and 0.05 mg/L).— Dilute 2.0, 1.0, and 0.5 mL myo- inositol intermediate standard to 100 mL with laboratory water (4, 2, and 1 mg/L). Dilute 0.5 mL myo-inositol intermediate standard to 200 mL with laboratory water (0.5 mg/L). Dilute 4 and 1 mL of the 0.5 mg/L myo-inositol working standard to 10 mL with laboratory water (0.2 and 0.05 mg/L). Expiration: 2 weeks. ( d ) Hydrochloric acid, 0.5%.— Add 1.25 mL concentrated hydrochloric acid to approximately 200 mL water in a 250 mL volumetric flask. Dilute to volume with water and mix well. Expiration: 6 months. ( e ) Sodium chloride, 1 N.— Dissolve 5.8 g sodium chloride and dilute to 100 mL with water. Expiration: 1 month. ( f ) Sodium hydroxide, 0.12% or 30 mM (Pump 1).— Quickly weigh 4.8 (±0.1) g of 50% sodium hydroxide into a 2000 mL volumetric flask containing approximately 1900 mL water. ( Note : It is important that the sodium hydroxide does not absorb carbon dioxide from the air.) Swirl to mix well. Dilute to volume with water and mix well. Expiration: 1 month. ( g ) Sodium hydroxide, 34 .0% or 750 m1 M (Pump 2).— Quickly weigh 1 62 0 (±3) g of 50% sodium hydroxide into a 2000 mL volumetric flask containing approximately 1900 mL water. ( Note : It is important that the sodium hydroxide does not absorb carbon dioxide from the air.) Swirl to mix well. Dilute to volume with water and mix well. Expiration: 1 month. ( h ) 6% Metaphosphoric acid.— Weigh 6.0 g metaphosphoric acid into a 100 mL volumetric flask. Dissolve and dilute to volume with laboratory water. Mix well. Store refrigerated. Expiration: 1 week. D. Preparation of Reagents and Standard Solutions

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