Testing Method of 2-Ethylanthraquinone (2-EAQ)
5 Testing method
5.1 General
Criterion of test result according to 4.3.3 of GB/T-8170-2008.
5.2 Determination of appearance.
By eyes.
5.3 Determination of melting point
    Dry sample at 80℃±5℃ 2h by capillary method referred GB/T 2384-2007.
5.4 Determination of purity
5.4.1 Reversed phase high-performance liquid chromatography, RP-HPLC at C18 Column, tested by UV detector and use area normalization method to determine the purity of 2-EAQ.
5.4.2  Devices
  a)RP-HPLC, Flow Range: 0.1ml/min~5.0ml/min stability ±1%.
    Multiwave UV Spectral Detector
  b) Columns: length 150mm, I.D. 6.0mm Stainless column, stationary phase C18 5um
  c) HPLC workstation
  d) Micro-syringe:10uL~25uL, Flat
  e) Ultrasonic generator
5.4.3 Reagent and Solution
  a) Methanol: Chromatography pure
  b) Tetrahydrofuran (THF): Chromatography pure
5.4.4 Chromatography conditions
  a) Mobile phase Methanol:water:THF=8:1:1 (volume)
  b) Wavelength 254um
  c) Traffic 1.0mL/min
  d) Injection volume 5uL
5.4.5 Preparation of sample solution
  Weigh dry grinded sample 0.025g (accurate to 0.0002g), put into 25mL flask, diluted by Methanol to the scale.
5.4.6 Step of test
Start chromatograph, in stable operation, injection of 5μL solution, and use HPLC workstation to analyze the results.
5.4.7 Calculation
Area normalization method
  ..........................................(1)
A－ peak area of 2-EAQ
∑Ai－Sum of the peak area of i components
5.4.8 Admissible error
High grade and firs grade ≤0.02%
Pass grade ≤0.2%
5.4.9 Chromatogram
(See Chinese version)
1. Unknown
2. Unknown
3. Unknown
4. 2-EAQ
5. Unknown
5.5 Determination of insoluble in benzene
weigh翻译  5.5.1 Put the sample through fat extractor, dry and weight. Calculate the insoluble in benzene according to the weight reduction of the sample.
5.5.2 Device
Fat extractor 250mL
5.5.3 Reagent
      Benzene
5.5.4 Steps
  Weigh sample 1.0g (accurate to 0.0002g), put into filter paper tube which is constant, fix into fat extractor with 250mL benzene, take out after 2.5h circumfluence. Put filter paper tube into oven at 100℃±5℃ for 2h, than weigh it.
5.5.5 Calculation
  ...................................(2)
m1—Weight value of filter paper tube (g)
m2---Total weight value of filter paper tube and insoluble in benzene (g)
m---Weight value of sample (g)
5.5.6 Admissible error
High grade and firs grade ≤0.02%
Pass grade ≤0.2%
5.6 Determination of moisture
    Weigh sample 2g, dry temp. 80℃, 30min, others refer to GB/T 2386-2006 chapter3.2 “drying method” to test the moisture.
5.7  Determination of iron (Fe)
    5.7.1 Reduce iron in the sample from Fe3+ to Fe2+ by ascorbic acid, and at PH=2~9 the orange-red complex can formed by reaction of Fe2+ with Phenanthroline. Compare complex with standard iron-color value by eyes.
    5.7.2  Devices
    a) Colorimetric tube 25mL
    b) Pipette 1mL, 5mL, 10mL
    c) Porcelain Crucible 30mL
    d) High-temperature furnace 700℃±25℃
5.7.3 Reagent and Solution
a) Ferrous ammonium sulfate
b) Ascorbic acid solution 2g/L
c) Acetic acid-sodium acetate buffer pH=4.5
d) Nitric acid solution, Nitric acid : water=1:9 in volume
e) Phenanthroline solution 0.2g/L
5.7.4 Preparation of standard solution
5.7.4.1 Iron standard solution (c=0.1mg/mL)
  Exactly weigh 0.702g((accurate to 0.0002g) Ferrous ammonium sulfate, soluble in water with 0.5mL sulphuric acid, transfer into 1,000mL flask and be diluted at scale which is standard solution A.
5.7.4.2 Iron standard solution (c=0.001mg/mL)
  Exactly suck 1mL standard solution A and put into 100mL flask, add water to dilute, shake well. Must prepare when using (Standard solution B).
    5.7.5 Steps.
    Exactly weigh 2.g sample (accurate to 0.0002g) and put into 30mL porcelain crucible, carbonized on oven then transfer into high-temperature furnace and calcine for 4h at 700℃±25℃. Take out the residua to cool it to room temperature, add 1mL nitric acid solution to be soluble then transfer into 100mL flask. Wash the crucible with hot water and diluted by water to the scale and shake well. Get 10mL sample solution and get standard solution B as 0.6mL, 0.8mL,1.0mL,……2.0mL, and put into 25mL colorimetric tube, add 1mL ascorbic
acid solution, 5mL acetic acid-sodium acetate buffer (pH=4.5), 1mL Phenanthroline solution and dilute to the scale and shake well. Compare the red color with standard iron-color value after putting 15min.

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