原文由 madprodigy 发表:
能否更详细点?只有这些可能很难知道你那数字导致代表什么
我刚开始也想着跟配制溶液的浓度有关,但是搞了半天,也没有弄明白。下面是整个测定的过程:
Determination of the impurity(1,3-dimethylurea) of technical Carbaryl
1. Apparatus and reagent
Instrument: Agilent 1100 Series LC
Column: Zorbax XDB-C8, 3.5µ, 150mm×4.6mm (i.d.)
Standard 1,3-dimethylurea: 99.4%
Methol: HPLC grade
Water: deionized twice distilled water
2. Liquid chromatographic conditions
Mobile phase: 0~2 min, Methanol: H2O = 35:65
2~5 min, Methanol: H2O = 90:10
Wavelength: 210nm
Flow: 1ml/min
Column temperature: 35℃
Injection amout: 5µl
Quantity method: external standard method (peak area)
3. Preparation of Standard solution
Accurately weigh 50mg (accuracy to 0.0002mg) of standard 1,3-dimethylurea into 25ml volumetric flask, dilute it to the mark with methanol and shake it evenly; Then exactly take 0.30ml standard solution into 10ml volumetric flask, dilute it in 7ml methanol, then dilute it to the mark with the mobile phase and shake evenly.
4. Preparation of sample solution
Accurately weigh 250mg (accuracy to 0.0002mg) of technical Carbaryl into 10ml volumetric flask, dilute it in 7ml methanol, then dilute it to the mark with the mobile phase and shake evenly.
5. Dertermination
According to the above chromatographic conditions, inject samples a couple of times until the variation of the peak area ratio of the two injections is less than 1%, follow the injection order below:
a: standard solution b: sample solution
c: sample solution d: standard solution
6. Calculation
1,3-dimethylurea content Pg% is calculated by the following equation:
Pg% =(m1×A2×P)/(83.3×m2×A1)
A1: In standard solution, average peak area of 1,3-dimethylurea
A2: In sample solution, average peak area of 1,3-dimethylurea
m1 : Amount of standard 1,3-dimethylurea, g
m2: Amount of sample Carbaryl, g
P: Percent of standard 1,3-dimethylurea, %(m/m)
Pg: Percent of impurity 1,3-dimethylurea, %(m/m)