Method III 方法III pH 3.5醋酸盐缓冲液:按照方法I所述配制。 标准溶液:取硫酸8mL和硝酸10mL,置于一清洁干燥的100mL凯氏烧瓶中,再加入与加到供试品中的硝酸等体积的硝酸。加热溶液至生成浓密的白烟;冷却,小心加水10mL。如果供试溶液用过氧化氢处理过,则加入与供试溶液所用等量的30%过氧化氢。轻微煮沸至生成浓...
操作步骤分别在标准溶液供试液的比色管中加入2ml醋酸缓冲溶液ph35然后加12ml硫代乙酰胺甘油基准试剂加水稀释到50ml摇匀放置2分钟同置白色背景下至上向下透视供试品溶液的颜色不得深于标准溶液的颜色 Method II 方法Ⅱ pH 3.5 Acetate Buffer— Prepare as directed under Method I. 取醋酸铵25.0g,加水25ml溶解后,加...
1 / 4 USP231重金属本检验用以证实供试品中与硫离子作用显色的金属杂质含量, 在规定检验条件下,不超过个论中规定的供试品重金属限度,以铅百分含量(重量比)计,与用标准铅溶液配制的对照进行目测比较(参看分光光度法和光散射法 851中操作步骤部分的视觉比较)测定。 [ 注意:与本检验起反应的代表性物质为铅、...
Residue on ignition (USP 281) Heavy metal test method (USP 231, Method II) Loss on ignition test method (USP 733) ▲图 2. 湿法灰化系统示意图,由湿法消解仪B-440(左)和尾气吸收仪K-415(右)组成。 湿法消解仪 B-440 将样品加热到高达 600°C 的温度,尾气吸收仪提供多步骤进行吸收,以确保完全中...
Method II 方法Ⅱ pH Acetate Buffer — Prepare as directed under Method I. 取醋酸铵 ,加水 25ml 溶解后, 加 盐酸 , 如有必要用 6N 氨水或 6N 盐酸调 PH至 ,用水稀释至 100ml,摇匀。 Standard Preparation — Prepare as directed under Method I. ...
Heavy metal test method (USP 231, Method II) Loss on ignition test method (USP 733) ▲图 2. 湿法灰化系统示意图,由湿法消解仪B-440(左)和尾气吸收仪K-415(右)组成。 湿法消解仪 B-440 将样品加热到高达 600°C 的温度,尾气吸收仪提供多步骤进行吸收,以确保中和吸收灰化过程中产生的有害烟雾。
Method III, a wet-digestion method, is used only in those cases where neither Method I nor Method II can be used Special Reagents Lead Nitrate Stock Solution— Dissolve 159.8 mg of lead nitrate in 100 mL of water to which has been added 1 mL of nitric acid, then dilute with water to...
[NOTE-If the color of the Monitor Preparation is lighter than that of the Standard Preparation, use Method II instead of Method I for the substance being tested。 ] 步骤:在标准品、供试品和监控品中各加pH 3.5醋酸盐缓冲液2 mL,然后加硫代乙酰胺—甘油基底试液1.2 mL,用水稀释至50 mL,混匀,...
Method II is used for substances that do not yield clear, colorless preparations under the test conditions specified for Method I, or for substances that, by virtue of their complex nature, interfere with the precipitation of metals by sulfide ion, or for fixed and volatile oils. Method III,...
Method III a wet digestion method is used only in those cases where neither Method I nor Method II can be used 除个论另有规定外 用方法 I 测定重金属含量 方法 I 用于规定条件下可生 成无色的 透明的制品的物质 方法 II 适用于在方法 I 规定条件下无法生成无 色透明制品的物质 或由于自身复杂...