 |
 |
 |
 |
 |
 |
||
 |
 |
 |
 |
 |
| 5 | 1/1 | 返回列表 |
| 查看: 1685 | 回復(fù): 4 | |||
kerxin新蟲 (小有名氣)
|
[交流]
【求助】求美國藥典，VB12與VB2的含量測定方法
|
| 求美國藥典，VB12與VB2的含量測定方法 |
回復(fù)此樓» 猜你喜歡
【考研調(diào)劑】化學(xué)專業(yè) 281分，一志愿四川大學(xué)，誠心求調(diào)劑
已經(jīng)有8人回復(fù)
-
一志愿華南師大 070300（化學(xué)）304分求調(diào)劑
已經(jīng)有3人回復(fù)
-
一志愿 西北大學(xué) ，070300化學(xué)學(xué)碩，總分287，雙非一本，求調(diào)劑。
已經(jīng)有3人回復(fù)
-
一志愿重慶大學(xué)085700資源與環(huán)境專碩，總分308求調(diào)劑
已經(jīng)有3人回復(fù)
-
354求調(diào)劑
已經(jīng)有8人回復(fù)
-
304求調(diào)劑
已經(jīng)有6人回復(fù)
-
一志愿西南交大，求調(diào)劑
已經(jīng)有5人回復(fù)
-
299求調(diào)劑
已經(jīng)有5人回復(fù)
-
材料專業(yè)求調(diào)劑
已經(jīng)有6人回復(fù)
-
311求調(diào)劑
已經(jīng)有5人回復(fù)
» 本主題相關(guān)價值貼推薦，對您同樣有幫助:
- 抗血清的純化方法
已經(jīng)有10人回復(fù)
- 求助：甲醇鈉存在下如何檢測反應(yīng)混合液的成分，分別測定轉(zhuǎn)化率和收率？
已經(jīng)有4人回復(fù)
- 有什么手段可以測無機(jī)物各元素含量
已經(jīng)有22人回復(fù)
- 學(xué)位論文里引用他人方法的問題
已經(jīng)有5人回復(fù)
- 初學(xué)者 求單體轉(zhuǎn)化率的方法
已經(jīng)有14人回復(fù)
- 利用DPPH測定抗氧化性的實驗數(shù)據(jù)處理問題哦
已經(jīng)有10人回復(fù)
- 分光光度計測定酶活中的問題
已經(jīng)有9人回復(fù)
- 關(guān)于Thermo Fisher Scientific Exactive高分辨質(zhì)譜系統(tǒng)能否測定蛋白
已經(jīng)有8人回復(fù)
- 廢水、廢氣的治理方法
已經(jīng)有19人回復(fù)
- 反射薄膜測試方法
已經(jīng)有9人回復(fù)
- DMA分析測定雙連續(xù)結(jié)構(gòu)玻璃化溫度盡然升高了？正常嗎？
已經(jīng)有3人回復(fù)
- 真菌測定技術(shù)
已經(jīng)有6人回復(fù)
- XRD粉晶衍射制樣方法（不是原創(chuàng)，網(wǎng)上轉(zhuǎn)來）
已經(jīng)有8人回復(fù)
- 福林酚法測總酚含量
已經(jīng)有25人回復(fù)
kerxin(金幣+3): 2010-09-07 12:14:37
|
Cyanocobalamin C63H88CoN14O14P 1355.37 Vitamin B12. Vitamin B12 [68-19-9]. » Cyanocobalamin contains not less than 96.0 percent and not more than 100.5 percent of C63H88CoN14O14P, calculated on the dried basis. Packaging and storage— Preserve in tight, light-resistant containers, and store at controlled room temperature. USP Reference standards 11 — USP Cyanocobalamin RS. Identification— A: The absorption spectrum of the solution employed for measurement of absorbance in the Assay exhibits maxima within ±1 nm at 278 nm and 361 nm and within ±2 nm at 550 nm. The ratio A361/A278 is between 1.70 and 1.90, and the ratio A361/A550 is between 3.15 and 3.40. B: Fuse about 1 mg with about 50 mg of potassium pyrosulfate in a porcelain crucible. Cool, break up the mass with a glass rod, add 3 mL of water, and dissolve by boiling. Add 1 drop of phenolphthalein TS, and add sodium hydroxide solution (1 in 10), dropwise, until just pink. Add 500 mg of sodium acetate, 0.5 mL of 1 N acetic acid, and 0.5 mL of nitroso R salt solution (1 in 500): a red or orange-red color appears at once. Add 0.5 mL of hydrochloric acid, and boil for 1 minute: the red color persists. C: Dissolve about 5 mg in 5 mL of water in a 50-mL distilling flask connected with a short, water-cooled condenser. To the flask add 2.5 mL of hypophosphorous acid, close, boil gently but short of distillation for 10 minutes, then distill 1 mL into a test tube containing 1 mL of sodium hydroxide solution (1 in 50). To the test tube add 4 drops of cold saturated ferrous ammonium sulfate solution, shake gently, then add about 30 mg of sodium fluoride, and bring the contents to a boil. Immediately add, dropwise, 5 N sulfuric acid until a clear solution results, then add 3 to 5 drops more of the acid: a blue or blue-green color develops within a few minutes. Loss on drying 731 — Heat about 25 mg, accurately weighed, in a suitable vacuum drying apparatus at 105 and at a pressure of not more than 5 mm of mercury for 2 hours, cool, and weigh: it loses not more than 12.0% of its weight. Pseudo cyanocobalamin— Dissolve 1.0 mg in 20 mL of water contained in a small separator, add 5 mL of a mixture of equal volumes of carbon tetrachloride and m-cresol, and shake well for about 1 minute. Allow to separate, draw off the lower layer into a second small separator, add 5 mL of 5 N sulfuric acid, shake well, and allow to separate completely (the complete separation of the layer may be facilitated by centrifuging): the separated upper layer is colorless or has no more color than a mixture of 0.15 mL of 0.10 N potassium permanganate and 250 mL of water. Assay— Transfer about 30 mg of Cyanocobalamin, accurately weighed, with the aid of water to a 1-L volumetric flask, dilute with water to volume, and mix. Dissolve an accurately weighed quantity of USP Cyanocobalamin RS in water, and dilute quantitatively and stepwise with water to obtain a Standard solution having a known concentration of about 30 µg per mL. Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 361 nm, with a suitable spectrophotometer, using water as the blank. Calculate the quantity, in mg, of C63H88CoN14O14P in the Cyanocobalamin taken by the formula: C(AU / AS) in which C is the concentration, in µg per mL, of USP Cyanocobalamin RS in the Standard solution; and AU and AS are the absorbances of the solution of Cyanocobalamin and the Standard solution, respectively. Auxiliary Information— Please check for your question in the FAQs before contacting USP. Topic/Question Contact Expert Committee Monograph Curtis Phinney 1-301-816-8540 (DSN05) Dietary Supplements - Non-Botanicals Reference Standards Lili Wang, Technical Services Scientist 1-301-816-8129 RSTech@usp.org USP32–NF27 Page 2036 Pharmacopeial Forum: Volume No. 31(5) Page 1350 Riboflavin C17H20N4O6 376.36 Riboflavine. Riboflavine [83-88-5]. » Riboflavin contains not less than 98.0 percent and not more than 102.0 percent of C17H20N4O6, calculated on the dried basis. Packaging and storage— Preserve in tight, light-resistant containers. USP Reference standards 11 — USP Riboflavin RS. Identification— A solution of 1 mg in 100 mL of water is pale greenish yellow by transmitted light, and has an intense yellowish-green fluorescence that disappears upon the addition of mineral acids or alkalies. Specific rotation 781S : between –115 and –135 . Test solution: 5 mg per mL, in 0.05 M sodium hydroxide free from carbonate. Measure the specific rotation within 30 minutes of preparation. Loss on drying 731 — Dry about 500 mg at 105 for 2 hours: it loses not more than 1.5% of its weight. Residue on ignition 281 : not more than 0.3%. Limit of lumiflavin— Prepare alcohol-free chloroform just prior to use, as follows. Shake 20 mL of chloroform gently but thoroughly with 20 mL of water for 3 minutes, draw off the chloroform layer, and wash twice more with 20-mL portions of water. Finally, filter the chloroform through a dry filter paper, shake it for 5 minutes with 5 g of powdered anhydrous sodium sulfate, allow the mixture to stand for 2 hours, and decant or filter the clear chloroform. Shake 25 mg of Riboflavin with 10 mL of the alcohol-free chloroform for 5 minutes, and filter: the absorbance of the filtrate, determined in 1-cm cells at a wavelength of 440 nm, with a suitable spectrophotometer, alcohol-free chloroform being used as the blank, does not exceed 0.025. Assay— [note—Conduct the entire procedure without exposure to direct sunlight.] Place about 50 mg of Riboflavin, accurately weighed, in a 1000-mL volumetric flask containing about 50 mL of water. Add 5 mL of 6 N acetic acid and sufficient water to make about 800 mL. Heat on a steam bath, protected from light, with frequent agitation until dissolved. Cool to about 25 , dilute with water to volume, and mix. Dilute this solution quantitatively and stepwise with water to bring it within the operating sensitivity of the fluorometer used. In the same manner, prepare a Standard solution to contain, in each mL, an accurately weighed quantity, of USP Riboflavin RS, equivalent to that of the Riboflavin solution prepared as directed above, and measure the intensity of its fluorescence in a fluorometer at about 530 nm. (An excitation wavelength of about 444 nm is preferable.) Immediately after the reading, add to the solution about 10 mg of sodium hydrosulfite, stirring with a glass rod until dissolved, and at once measure the fluorescence again. The difference between the two readings represents the intensity of the fluorescence due to the Standard. Similarly, measure the intensity of the fluorescence of the final solution of the Riboflavin being assayed at about 530 nm, before and after the addition of sodium hydrosulfite. Calculate the quantity, in µg per mL, of C17H20N4O6 in the final solution of Riboflavin taken by the formula: C(IU / IS) in which C is the concentration, in µg per mL, of USP Riboflavin RS in the final solution of the Standard, and IU and IS are the corrected fluorescence values observed for the solutions of the Riboflavin and Standard, respectively. Auxiliary Information— Please check for your question in the FAQs before contacting USP. Topic/Question Contact Expert Committee Monograph Curtis Phinney 1-301-816-8540 (DSN05) Dietary Supplements - Non-Botanicals Reference Standards Lili Wang, Technical Services Scientist 1-301-816-8129 RSTech@usp.org USP32–NF27 Page 3497 Pharmacopeial Forum: Volume No. 30(3) Page 929 Chromatographic Column— RIBOFLAVIN Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27. |
2樓2010-09-07 11:33:23
kerxin
新蟲 (小有名氣)
- 應(yīng)助: 0 (幼兒園)
- 金幣: 17.8
- 散金: 19
- 帖子: 65
- 在線: 14小時
- 蟲號: 987373
- 注冊: 2010-04-01
- 性別: MM
- 專業(yè): 藥物分析
3樓2010-09-09 16:20:01
4樓2010-09-23 10:25:27
5樓2015-11-24 15:35:43
相關(guān)版塊跳轉(zhuǎn)
我要訂閱樓主 kerxin 的主題更新
| 5 | 1/1 | 返回列表 |
| 最具人氣熱帖推薦 [查看全部] | 作者 | 回/看 | 最后發(fā)表 | |
|---|---|---|---|---|
|
[考研] 一志愿 西北大學(xué) ，070300化學(xué)學(xué)碩，總分287，雙非一本，求調(diào)劑。 +3 | 晨昏線與星海 2026-03-18 | 3/150 |
|
|---|---|---|---|---|
|
[考研] 295求調(diào)劑 +4 | 一志愿京區(qū)211 2026-03-18 | 6/300 |
|
|
|
[考研] 一志愿南昌大學(xué)，327分，材料與化工085600 +9 | Ncdx123456 2026-03-19 | 9/450 |
|
|
|
[考研] 304求調(diào)劑 +7 | 司空. 2026-03-18 | 7/350 |
|
|
|
[考研] 350求調(diào)劑 +5 | weudhdk 2026-03-19 | 5/250 |
|
|
|
[考研] 329求調(diào)劑 +9 | 想上學(xué)吖吖 2026-03-19 | 9/450 |
|
|
|
[考研] 一志愿西南交通 專碩 材料355 本科雙非 求調(diào)劑 +5 | 西南交通專材355 2026-03-19 | 5/250 |
|
|
|
[考研] 一志愿華中農(nóng)業(yè)071010，總分320求調(diào)劑 +3 | 困困困困坤坤 2026-03-20 | 3/150 |
|
|
|
[考研] 281求調(diào)劑（0805） +14 | 煙汐憶海 2026-03-16 | 25/1250 |
|
|
|
[考研] 0703化學(xué)調(diào)劑 +5 | pupcoco 2026-03-17 | 8/400 |
|
|
|
[考研] 328求調(diào)劑，英語六級551，有科研經(jīng)歷 +4 | 生物工程調(diào)劑 2026-03-16 | 12/600 |
|
|
|
[考研] 0817調(diào)劑 +3 | 沒有答案_ 2026-03-14 | 3/150 |
|
|
|
[考研] 一志愿華中科技大學(xué)，080502，354分求調(diào)劑 +4 | 守候夕陽CF 2026-03-18 | 4/200 |
|
|
|
[考研] 311求調(diào)劑 +11 | 冬十三 2026-03-15 | 12/600 |
|
|
|
[考研] 0703化學(xué)調(diào)劑 +3 | 妮妮ninicgb 2026-03-17 | 3/150 |
|
|
|
[考研] 材料，紡織，生物（0856、0710），化學(xué)招生啦 +3 | Eember. 2026-03-17 | 9/450 |
|
|
|
[考研] 268求調(diào)劑 +6 | 簡單點0 2026-03-17 | 6/300 |
|
|
|
[考研] 機(jī)械專碩325，尋找調(diào)劑院校 +3 | y9999 2026-03-15 | 5/250 |
|
|
|
[考研] 288求調(diào)劑 +4 | 奇點0314 2026-03-14 | 4/200 |
|
|
|
[考研] 289求調(diào)劑 +4 | 這么名字咋樣 2026-03-14 | 6/300 |
|