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[求助]
气相色谱检测方法问题，请教大家！！
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这个方法是做顶空的吗？ 各位老师，帮帮忙，小弟是新手。 这是整个气相方法： TESTS pH (2.2.3): 6.5 to 7.5. Dissolve 0.20 g in carbon dioxide-free water R and dilute to 10 mL with the same solvent. Impurity C. Gas chromatography (2.2.28). Silylation solution. To 2 mL of N,O-bis(trimethylsilyl)tri- fluoroacetamide R add 0.04 mL of chlorotrimethylsilane R and mix. Test solution.Dissolve50.0mgofthesubstancetobeexamined in 3 mL of water R and add 0.5 mL of hydrochloric acid R. Extract with 2 quantities, each of 5 mL, of methylenechlorideR. Evaporate the combined methylene chloride extracts to dryness in a vial with a screw cap and add 0.5 mL of the silylation solution.Sealthevialandheatat70±5°Cfor20min. Reference solution (a).Dissolve5.0mgof sodium phenylbutyrate impurity C CRS in methylenechlorideR and dilute to 10.0 mL with the same solvent. Reference solution (b). Dilute 1.0 mL of reference solution (a) to 10.0 mL with methylenechlorideR.Place1.0mLofthis solution in a vial with a screw cap, evaporate to dryness and add 0.5 mL of the silylation solution. Seal the vial and heat at 70±5°Cfor20min. Reference solution (c). Dissolve 10 mg of the substance to be examined in 25 mL of water R. To 3 mL of this solution add 0.1 mL of hydrochloric acid R. Extract with 2 quantities, each of 5 mL, of methylene chloride R. Combine the methylene chloride extracts in a vial with a screw cap and add 2 mL of reference solution (a). Evaporate to dryness and add 0.5 mL of the silylation solution. Seal the vial and heat at 70 ± 5 °C for 20 min. Column: — material :fusedsilica; — size: l =25m,?=0.25mm; — stationary phase: poly(dimethyl)(diphenyl)siloxane R (film thickness 1.0 μm). Carrier gas : helium for chromatography R. Flow rate:0.9mL/min. Split ratio: 1:100. Temperature: Time(min) Temperature(°C) Column 0-5 50 5 - 27 50 → 270 27 – 32 270 Injection port 270 Detector 270 Detection:flameionisation. Injection:1 μL. Relative retention with reference to phenylbutyrate (retention time = about 20 min) : impurity C = about 0.98. System suitability: reference solution (c) : — resolution: minimum 3.0 between the peaks due to impurity C and phenylbutyrate. Limit : — impurity C:notmorethantheareaofthecorresponding peak in the chromatogram obtained with reference solution (b) (0.1 per cent). Related substances. Liquid chromatography (2.2.29). 这个方法是不是顶空方法，如果是的话，里面怎么没有顶空条件？难道是硅烷化反应的条件就包含了顶空条件（Seal the vial and heat at 70 ± 5 °C for 20 min.）还是说顶空条件要自己摸索？ |
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3楼2012-02-09 13:27:31
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4楼2012-02-09 17:01:38
