USP35-231重金屬

1、 1 / 10USP35 HEAVY METALS重金屬重金屬This test is provided to demonstrate that the content of metallic impurities that are colored by sulfide ion, under the specified test conditions, does not exceed the Heavy metals limit specified in the individual monograph in percentage (by weight) of lead in the test

2、 substance, as determined by concomitant visual comparison (see Visual Comparison in the section Procedure under Spectrophotometry and Light-Scattering 851 ) with a control prepared from a Standard Lead Solution. NOTESubstances that typically will respond to this test are lead, mercury, bismuth, ars

3、enic, antimony, tin, cadmium, silver, copper, and molybdenum. 本檢驗(yàn)用以證實(shí)供試品中與硫離子作用顯色的金屬雜質(zhì)含量，在規(guī)定檢驗(yàn)條件下，不超過(guò)個(gè)論中規(guī)定的供試品重金屬限度，以鉛百分含量（重量比）計(jì)，與用標(biāo)準(zhǔn)鉛溶液配制的對(duì)照進(jìn)行目測(cè)比較（參看分光光度法和光散射法中操作步驟部分的視覺比較）測(cè)定。注意：與本檢驗(yàn)起反應(yīng)的代表性物質(zhì)為鉛、汞、鉍、砷、銻、錫、鎘、銀、銅和鉬。Determine the amount of heavy metals by Method I, unless otherwise specified in the ind

4、ividual monograph. Method I is used for substances that yield clear, colorless preparations under the specified test conditions. 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 the

5、ir complex nature, interfere with the precipitation of metals by sulfide ion, or for fixed and volatile oils. Method III, a wet-digestion method, is used only in those cases where neither Method I nor Method II can be used.除個(gè)論另有規(guī)定外，用方法 I 測(cè)定重金屬含量。方法 I 用于規(guī)定條件下可生成無(wú)色的、透明的制品的物質(zhì)。方法 II 適用于在方法 I 規(guī)定條件下無(wú)法生成無(wú)色

6、透明制品的物質(zhì)，或由于自身復(fù)雜特性，會(huì)對(duì)硫離子生成的金屬沉淀造成干 2 / 10擾的物質(zhì)，以及不揮發(fā)油和揮發(fā)油。方法 III 濕消化法，僅在方法 I 和方法 II 均不適用時(shí)使用。Special Reagents專用試劑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 1000 mL. Prepare and store this soluti

7、on in glass containers free from soluble lead salts. 硝酸鉛貯備液：取硝酸鉛 159.8 mg，加已加硝酸 1 mL 的水 100 mL，溶解，加水稀釋至 1000 mL。于不含可溶鉛鹽的玻璃容器中配制和貯存該溶液。Standard Lead Solution On the day of use, dilute 10.0 mL of Lead Nitrate Stock Solution with water to 100.0 mL. Each mL of Standard Lead Solution contains the equival

8、ent of 10 g of lead. A comparison solution prepared on the basis of 100 L of Standard Lead Solution per g of substance being tested contains the equivalent of 1 part of lead per million parts of substance being tested. 標(biāo)準(zhǔn)鉛溶液：使用當(dāng)天配制。取硝酸鉛貯備液 10.0 mL，加水稀釋至100.0 mL。每 mL 標(biāo)準(zhǔn)鉛溶液相當(dāng)于 10 g 的鉛。以每 g 供試品 100L 標(biāo)準(zhǔn)

9、鉛溶液為基準(zhǔn)制備的參比溶液相當(dāng)于每一百萬(wàn)份供試品中含有一份鉛。METHOD I 方法 IpH 3.5 Acetate Buffer Dissolve 25.0 g of ammonium acetate in 25 mL of water, and add 38.0 mL of 6 N hydrochloric acid. Adjust, if necessary, with 6 N ammonium hydroxide or 6 N hydrochloric acid to a pH of 3.5, dilute with water to 100 mL, and mix. pH 3.5 醋

10、酸鹽緩沖液：取醋酸銨 25.0 g，加水 25 mL，溶解，加 6 N 鹽酸38.0 mL。如有需要，用 6 N 氨水或 6 N 鹽酸調(diào)節(jié) pH 為 3.5，用水稀釋至 100 mL?；靹颉tandard Preparation Into a 50-mL color-comparison tube pipet 2 mL of Standard Lead Solution (20 g of Pb), and dilute with water to 25 mL. Using a 3 / 10pH meter or short-range pH indicator paper as extern

11、al indicator, adjust with 1 N acetic acid or 6 N ammonium hydroxide to a pH between 3.0 and 4.0, dilute with water to 40 mL, and mix. 標(biāo)準(zhǔn)溶液：用移液管取標(biāo)準(zhǔn)鉛溶液 2 mL（20 g 的鉛），置 50 mL 比色管中，用水稀釋至 25 mL。使用 pH 計(jì)或窄范圍 pH 試紙作外部指示劑，用 1 N醋酸或 6 N 氨水調(diào)節(jié) pH 至 3.0-4.0，用水稀釋至 40 mL，混勻。Test Preparation Into a 50-mL color-compa

12、rison tube place 25 mL of the solution prepared for the test as directed in the individual monograph; or, using the designated volume of acid where specified in the individual monograph, dissolve in and dilute with water to 25 mL the quantity, in g, of the substance to be tested, as calculated by th

13、e formula: 2.0/(1000L),in which L is the Heavy metals limit, as a percentage. Using a pH meter or short-range pH indicator paper as external indicator, adjust with 1 N acetic acid or 6 N ammonium hydroxide to a pH between 3.0 and 4.0, dilute with water to 40 mL, and mix. 供試溶液：取如個(gè)論所述制備的供試液 25 mL，置 50

14、 mL 比色管中；或當(dāng)個(gè)論另有規(guī)定時(shí)，使用個(gè)論中規(guī)定體積量的酸溶解，并用水稀釋至 25 mL。按下公式計(jì)算供試品的量（單位 g），2.0/(1000L),公式中，L 是重金屬限度，以百分?jǐn)?shù)計(jì)。使用 pH 計(jì)或窄范圍 pH 試紙作外部指示劑，用 1 N 醋酸或 6 N 氨水調(diào)節(jié) pH 至 3.0-4.0，用水稀釋至 40 mL，混勻。Monitor Preparation Into a third 50-mL color-comparison tube place 25 mL of a solution prepared as directed for Test Preparation, and

15、 add 2.0 mL of Standard Lead Solution. Using a pH meter or short-range pH indicator paper as external indicator, adjust with 1 N acetic acid or 6 N ammonium hydroxide to a pH between 3.0 and 4.0, dilute with water to 40 mL, and mix. 4 / 10監(jiān)控溶液：取如供試溶液所述制備的溶液 25 mL，置 50 mL 比色管中，加標(biāo)準(zhǔn)鉛溶液 2.0 mL，使用 pH 計(jì)或窄

16、范圍 pH 試紙作外部指示劑，用 1 N 醋酸或 6 N 氨水調(diào)節(jié) pH 至 3.0-4.0，用水稀釋至 40 mL，混勻。Procedure To each of the three tubes containing the Standard Preparation, the Test Preparation, and the Monitor Preparation, add 2 mL of pH 3.5 Acetate Buffer, then add 1.2 mL of thioacetamideglycerin base TS, dilute with water to 50 mL,

17、mix, allow to stand for 2 minutes, and view downward over a white surface *: the color of the solution from the Test Preparation is not darker than that of the solution from the Standard Preparation, and the color of the solution from the Monitor Preparation is equal to or darker than that of the so

18、lution from the Standard Preparation. NOTEIf 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. 操作：在標(biāo)準(zhǔn)溶液、供試溶液和監(jiān)控溶液中各加 pH 3.5 的醋酸鹽緩沖液 2 mL，然后加硫代乙酰胺-甘油燒堿試液 1.2 mL，用水稀釋至 50 mL，混勻，靜置 2 分鐘，置一白色表面上，自上向下觀察

19、：供試溶液與標(biāo)準(zhǔn)溶液的顏色比較，不得更深；監(jiān)控溶液與標(biāo)準(zhǔn)溶液的顏色比較，相當(dāng)或更深。注意：如果監(jiān)控溶液的顏色比標(biāo)準(zhǔn)溶液的顏色更淺，使用方法 II 代替方法 I 來(lái)檢測(cè)該供試品。METHOD II 方法 IINOTEThis method does not recover mercury. pH 3.5 Acetate Buffer Prepare as directed under Method I. Standard PreparationPrepare as directed under Method I. 注意：該方法不包含汞。pH 3.5 醋酸鹽緩沖液：按照方法 I 所述配制。標(biāo)準(zhǔn)溶液

20、：按照方法 I 所述配制。Test Preparation Use a quantity, in g, of the substance to be tested as calculated by the formula: 2.0/(1000L) 5 / 10in which L is the Heavy metals limit, in percentage. Transfer the weighed quantity of the substance to a suitable crucible, add sufficient sulfuric acid to wet the substa

21、nce, and carefully ignite at a low temperature until thoroughly charred. (The crucible may be loosely covered with a suitable lid during the charring.) Add to the carbonized mass 2 mL of nitric acid and 5 drops of sulfuric acid, and heat cautiously until white fumes no longer are evolved. Ignite, pr

22、eferably in a muffle furnace, at 500 to 600 , until the carbon is completely burned off. Cool, add 4mL of 6 N hydrochloric acid, cover, digest on a steam bath for 15minutes, uncover, and slowly evaporate on a steam bath to dryness. Moisten the residue with 1 drop of hydrochloric acid, add 10mL of ho

23、t water, and digest for 2 minutes, Add 6N ammonium hydroxide dropwise until the solution is just alkaline to litmus paper, dilute with water to 25 mL, and adjust with 1 N acetic acid to a pH between 3.0 and 4.0 , using short-rang pH indicator paper as an external indicator. Filter if necessary, rins

24、e the crucible and the filter with 10 mL of water, combine the filtrate and rinsing in a 50-mL color-comparison tube, dilute with water to 40mL, and mix.供試溶液：取按下述公式計(jì)算所得供試品的量（單位 g）2.0/(1000L)式中，L 是重金屬限度，以百分?jǐn)?shù)計(jì)。精密稱定后轉(zhuǎn)移至適宜坩堝中，加足量硫酸潤(rùn)濕供試品，在低溫下小心熾灼至完全炭化。（炭化時(shí)可用一適宜蓋子松蓋于坩堝上。）向炭化物加硝酸 2 mL，硫酸 5 滴，小心加熱至不再產(chǎn)生白色煙霧。

25、最好用馬弗爐于 500-600進(jìn)行熾灼，直至炭完全燃盡。放冷，加 6N鹽酸 4 mL，蓋蓋，在蒸汽浴中煮解 15 分鐘。打開蓋子，在蒸汽浴上緩慢蒸發(fā)至干。用 1 滴鹽酸潤(rùn)濕殘?jiān)?，?10ml 熱水，并煮解 2 分鐘，滴加 6N 的氨水，直到溶液恰呈堿性（用石蕊試紙檢查），用水稀釋至 25ml，用 1N 的醋酸調(diào)節(jié)pH 值為 3.0-4.0，用窄范圍的 pH 試紙作外指示劑。如有必要，可過(guò)濾，用10ml 水沖洗坩鍋和過(guò)濾器，將濾液與沖洗液一并移入 50-ml 比色管中，用水稀釋至 40ml，并混勻。 6 / 10ProcedureTo each of the tubes containing t

26、he Standard Preparation and the Test Preparation, add 2 mL of pH 3.5 Acetate Buffer, then add 1.2 mL of thioacetamide-glycerin base TS, dilute with water to 50 mL, mix, allow to stand for 2 minutes, and view downward over a white surface*: the color of the solution from the Test Preparation is not d

27、arker than that of the solution from the Standard Preparation. 步驟：分別向每個(gè)含有標(biāo)準(zhǔn)溶液和供試溶液的試管中加入 2mlpH 值為 3.5的醋酸鹽緩沖液，然后加入 1.2ml 硫代乙酰胺丙三醇 TS，用水稀釋至50ml，混勻，靜置 2 分鐘，在一白色表面上自上向下看：供試品溶液的顏色不得深于標(biāo)準(zhǔn)品溶液的顏色。 METHOD III方法方法 IIIpH 3.5 Acetate Buffer Prepare as directed under Method I. pH 3.5 醋酸鹽緩沖液：按照方法 I 所述配制。Standard P

28、reparation Transfer a mixture of 8 mL of sulfuric acid and 10 mL of nitric acid to a clean, dry, 100-mL Kjeldahl flask, and add a further volume of nitric acid equal to the incremental volume of nitric acid added to the Test Preparation. Heat the solution to the production of dense, white fumes; coo

29、l; cautiously add 10 mL of water; and, if hydrogen peroxide was used in treating the Test Preparation, add a volume of 30 percent hydrogen peroxide equal to that used for the substance being tested. Boil gently to the production of dense, white fumes. Again cool, cautiously add 5 mL of water, mix, a

30、nd boil gently to the production of dense, white fumes and to a volume of 2 to 3 mL. Cool, dilute cautiously with a few mL of water, add 2.0 mL of Standard Lead Solution (20 g of Pb), and mix. Transfer to a 50-mL color-comparison tube, rinse the flask with water, adding the rinsing to the tube until

31、 the volume is 25 mL, and mix. 標(biāo)準(zhǔn)溶液：取硫酸 8mL 和硝酸 10 mL，置于一清潔干燥的 100mL 凱氏燒瓶中，再加入與加到供試品中的硝酸等體積的硝酸。加熱溶液至生成濃密的白 7 / 10煙；冷卻，小心加水 10mL。如果供試溶液用過(guò)氧化氫處理過(guò)，則加入與供試溶液所用等量的 30%過(guò)氧化氫。輕微煮沸至生成濃密的白煙。再次冷卻，小心加水 5mL，混合，輕微煮沸至生成濃密的白煙，且體積為 2-3mL。冷卻，用少許（mL）水小心稀釋，加標(biāo)準(zhǔn)鉛溶液 2.0 mL（20 g 鉛），混勻。轉(zhuǎn)移至 50-mL 比色管中，用水沖洗燒瓶，將清洗液加至試管中，至體積為 25m

32、L，混合。Test Preparation Unless otherwise indicated in the individual monograph, use a quantity, in g, of the substance to be tested as calculated by the formula: 2.0/(1000L),in which L is the Heavy metals limit, as a percentage. 供試品：除個(gè)論中另有規(guī)定外，取用由下述公式計(jì)算所得的供試品量（單位 g）：2.0/(1000L)式中，L 是重金屬限度，以百分?jǐn)?shù)計(jì)。If the

33、substance is a solid Transfer the weighed quantity of the test substance to a clean, dry, 100-mL Kjeldahl flask. NOTEA 300-mL flask may be used if the reaction foams excessively. Clamp the flask at an angle of 45 , and add a sufficient quantity of a mixture of 8 mL of sulfuric acid and 10 mL of nitr

34、ic acid to moisten the substance thoroughly. Warm gently until the reaction commences, allow the reaction to subside, and add portions of the same acid mixture, heating after each addition, until a total of 18 mL of the acid mixture has been added. Increase the amount of heat, and boil gently until

35、the solution darkens. Cool, add 2 mL of nitric acid, and heat again until the solution darkens. Continue the heating, followed by addition of nitric acid until no further darkening occurs, then heat strongly to the production of dense, white fumes. Cool, cautiously add 5 mL of water, boil gently to

36、the production of dense, white fumes, and continue heating until the volume is reduced to a few mL. Cool, cautiously add 5 mL of water, and examine the color of the solution. If the color is yellow, cautiously add 1 mL of 30 percent 8 / 10hydrogen peroxide, and again evaporate to the production of d

37、ense, white fumes and a volume of 2 to 3 mL. If the solution is still yellow, repeat the addition of 5 mL of water and the peroxide treatment. Cool, dilute cautiously with a few mL of water, and rinse into a 50-mL color-comparison tube, taking care that the combined volume does not exceed 25 mL. 如果供

38、試品為固體：取供試品，精密稱定，轉(zhuǎn)移至一清潔干燥的 100-mL凱氏燒瓶中。注意：如果反應(yīng)起泡劇烈，可以使用 300-mL 燒瓶。 于 45角處夾緊燒瓶，加入硫酸 8mL 和硝酸 10 mL 的混合液足量，使供試品完全潤(rùn)濕。輕緩加溫至開始反應(yīng)，使反應(yīng)平息，加相同的酸混合液，每次加酸后繼續(xù)加熱，直至 18mL 酸混合液完全加入。增加加熱，緩慢煮沸至溶液變深。冷卻，加硝酸 2mL，再次加熱至溶液變深。繼續(xù)加熱，并加硝酸直至顏色不再進(jìn)一步加深，劇烈加熱至生成濃密的白煙。冷卻，小心加入水 5mL，緩慢煮沸至生成濃密的白煙，繼續(xù)加熱直到體積減少至幾 mL。冷卻，小心加入水 5mL，檢查溶液顏色。如果為黃

39、色，小心加入 30%過(guò)氧化氫 1mL，并再次蒸發(fā)至生成濃密的白煙，且體積剩 2-3mL。如果溶液仍呈黃色，再次加水 5mL，并用過(guò)氧化氫處理。冷卻，用少許的水小心稀釋，并沖入 50 mL 比色管中，小心最終體積不得超過(guò)25mL。If the substance is a liquid Transfer the weighed quantity of the test substance to a clean, dry, 100-mL Kjeldahl flask. NOTEA 300-mL flask may be used if the reaction foams excessively.

40、 Clamp the flask at an angle of 45 , and cautiously add a few mL of a mixture of 8 mL of sulfuric acid and 10 mL of nitric acid. Warm gently until the reaction commences, allow the reaction to subside, and proceed as directed for If the substance is a solid, beginning with “add portions of the same

41、acid mixture.” 如果供試品為液體：取精密稱定的供試品，置于一清潔干燥的 100mL 凱氏燒瓶中。注意：如果反應(yīng)起泡劇烈，可以使用 300-mL 燒瓶。 于 45角處夾緊燒瓶，小心加入硫酸 8mL 和硝酸 10 mL 的混合液少量。輕微加溫至反應(yīng)開始，使反應(yīng)平息，并按“如果供試品是固體：從加相同的酸混合液”處開始進(jìn)行操作。 9 / 10Monitor Preparation Proceed with the digestion, using the same amount of sample and the same procedure as directed in the sub

42、section If the substance is a solid in the section Test Preparation, until the step “Cool, dilute cautiously with a few mL of water.” Add 2.0 mL of Lead Standard Solution (20 g of lead), and mix. Transfer to a 50-mL color comparison tube, rinse the flask with water, adding the rinsing to the tube until the volume is 25 mL, and mix. 監(jiān)控溶液：進(jìn)行煮解，樣品量與操作與供試品項(xiàng)下“如果供試品是