| 5 | 1/1 | 返回列表 |
| 查看: 1524 | 回復(fù): 3 | |||
| 當(dāng)前只顯示滿足指定條件的回帖,點(diǎn)擊這里查看本話題的所有回帖 | |||
yangxicshe鐵蟲(chóng) (小有名氣)
|
[交流]
【求助】溶劑峰和藥峰總是重疊在一起了,應(yīng)該怎么調(diào)整比例? 已有3人參與
|
||
|
流動(dòng)相的最佳比例 各位資深人士,我是HPLC的新手,現(xiàn)在在做多西環(huán)素的HPLC的測(cè)定,在365nm的波長(zhǎng)下,流動(dòng)相是0.01M草酸-乙腈-甲醇,原來(lái)的比例是 50:35:15,但是溶劑峰和藥峰總是重疊在一起了,應(yīng)該怎么調(diào)整比例。考状,乙腈的吸收波長(zhǎng)又是多少呢?期盼回復(fù)! |
木蟲(chóng) (著名寫手)
藥學(xué)版~龍貓

木蟲(chóng) (正式寫手)
|
溶劑如果是流動(dòng)相,在365nm應(yīng)該沒(méi)有吸收啊 如果有峰,應(yīng)該很小,出峰時(shí)間也應(yīng)該很早的 USP33 ASSAY • Procedure Mobile phase: Transfer 2.72 g of monobasic potassium phosphate, 0.74 g of sodium hydroxide, 0.50 g of tetrabutylammonium hydrogen sulfate, and 0.40 g of edetate disodium to a 1000-mL volumetric flask. Add 850 mL of water, and stir to dissolve. Add 60 g of tertiary butyl alcohol with the aid of water, dilute with water to volume, and adjust with 1 N sodium hydroxide to a pH of 8.0 ± 0.1. Pass this solution through a filter having a porosity of 0.5 µm or finer, and degas before using. Decreasing the proportion of tertiary butyl alcohol results in a longer retention time of doxycycline and improved separation of doxycycline from the related compounds. Diluent: 0.01 N hydrochloric acid System suitability solution: Prepare a solution of USP Doxycycline Hyclate RS in Diluent containing about 6 mg of doxycycline/mL. Transfer 5 mL of this solution to a 25-mL volumetric flask, heat on a steam bath for 60 min, and evaporate to dryness on a hot plate, taking care not to char the residue. Dissolve the residue in 0.01 N hydrochloric acid, dilute with Diluent to volume, and mix. Pass a portion of this solution through a filter having a porosity of 0.5 µm or finer, and use the filtrate. This solution contains a mixture of 4-epidoxycycline, 6-epidoxycycline, and doxycycline. When stored in a refrigerator, this solution may be used for 14 days. [Note—Throughout the following procedures, protect the Standard solution and the Sample solution from light. ] Standard solution: Transfer 12 mg of USP Doxycycline Hyclate RS, to a 10-mL volumetric flask, add 6 mL of Diluent, sonicate for about 5 min or until dissolved, and dilute with Diluent to volume. Sample solution: 55 mg of Doxycycline in a 50-mL volumetric flask. Add 12 mL of 0.1 N hydrochloric acid, swirl to dissolve, and dilute with Diluent to volume. Filter through a filter of 0.5 µm or finer porosity. Chromatographic system (See Chromatography 621, System Suitability.) Mode: LC Detector: UV 270 nm Column: 4.6-mm × 25-cm; packing L21 Column temperature: 60 ± 1 Flow rate: 1 mL/min Injection size: 20 µL System suitability Sample: System suitability solution and Standard solution [Note—The relative retention times for 4-epidoxycycline (the main degradation product), 6-epidoxycycline, and doxycycline are 0.4, 0.7, and 1.0, respectively. ] Suitability requirements Resolution: NLT 3.0 between the 4-epidoxycycline peak and the doxycycline peak, System suitability solution Tailing factor: NMT 2.0, System suitability solution Relative standard deviation: NMT 2.0%, Standard solution Analysis Samples: Standard solution and Sample solution Calculate the quantity of C22H24N2O8, in µg, in each mg of the Doxycycline taken: Result = (rU/rS) × (CS/CU) × P rU = = peak response from the Sample solution rS = = peak response from the Standard solution CS = = concentration of USP Doxycycline Hyclate RS in the Standard solution (mg/mL) CU = = concentration of the Sample solution (mg/mL) P = = designated potency of doxycycline (C22H24N2O8), of USP Doxycycline Hyclate RS (µg/mg) Acceptance criteria: NLT 880 µg/mg and NMT 980 µg/mg |
| 最具人氣熱帖推薦 [查看全部] | 作者 | 回/看 | 最后發(fā)表 | |
|---|---|---|---|---|
|
[考研] 266求調(diào)劑 +11 | 陽(yáng)陽(yáng)哇塞 2026-03-27 | 12/600 |
|
|---|---|---|---|---|
|
[考研] 085602 化工專碩 338分 求調(diào)劑 +8 | 路癡小琪 2026-03-27 | 8/400 |
|
|
[考研] 283求調(diào)劑(080500) +4 | A child 2026-03-27 | 4/200 |
|
|
[考研] 化學(xué)308分求調(diào)劑 +8 | 你好明天你好 2026-03-23 | 9/450 |
|
|
[考研] 調(diào)劑 +3 | 李嘉圖·S·路 2026-03-27 | 3/150 |
|
|
[考研] 317求調(diào)劑 +7 | 蛋黃咸肉粽 2026-03-26 | 7/350 |
|
|
[考研] 333求調(diào)劑 +7 | 87639 2026-03-21 | 12/600 |
|
|
[考研] 325求調(diào)劑 +3 | Aoyijiang 2026-03-23 | 3/150 |
|
|
[考研] 303求調(diào)劑 +7 | 元夕元 2026-03-20 | 8/400 |
|
|
[考研] 生物學(xué)學(xué)碩,一志愿湖南大學(xué),初試成績(jī)338 +4 | YYYYYNNNNN 2026-03-26 | 4/200 |
|
|
[考研] 299求調(diào)劑 +7 | 某某某某位 2026-03-21 | 8/400 |
|
|
[考研] 生物技術(shù)與工程 +3 | 1294608413 2026-03-25 | 4/200 |
|
|
[考研] 求b區(qū)院校調(diào)劑 +4 | 周56 2026-03-24 | 5/250 |
|
|
[考研] 291求調(diào)劑 +3 | HanBeiNingZC 2026-03-24 | 3/150 |
|
|
[基金申請(qǐng)] 請(qǐng)教下大家 2026年國(guó)家基金申請(qǐng)是雙盲審嗎? +3 | lishucheng1 2026-03-22 | 5/250 |
|
|
[考研] 接收2026碩士調(diào)劑(學(xué)碩+專碩) +4 | allen-yin 2026-03-23 | 6/300 |
|
|
[考研] 280分求調(diào)劑 一志愿085802 +4 | PUMPT 2026-03-22 | 7/350 |
|
|
[考研] 求調(diào)劑一志愿海大,0703化學(xué)學(xué)碩304分,有大創(chuàng)項(xiàng)目,四級(jí)已過(guò) +6 | 幸運(yùn)哩哩 2026-03-22 | 10/500 |
|
|
[考研] 考研調(diào)劑 +3 | 呼呼?~+123456 2026-03-21 | 3/150 |
|
|
[考研] 材料與化工(0856)304求 B區(qū) 調(diào)劑 +3 | 邱gl 2026-03-21 | 3/150 |
|