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1.
Injection volume.- 5µL.
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2.
Autosampler temperature.- 10 °C.
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3.
Column temperature.- 25 °C.
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4.
Flow rate.- 0.35mL/min
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5.
Run time.- 4.0 minutes
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6. Mobile phase.- Sodium acetate (50 mmol/L, pH 5.4), decylamine (1.6g),
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acetonitrile (1 %), TCEP (40 mg/L).
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NOTE:
At the end of each analytical series, rinse column with acetonitrile-water (1+1, v/v)
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for 10 minutes at 0.4 ml/min
.
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(b).
System suitability test
.- Equilibrate the chromatographic system for ≥0.5 h.
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Inject a working standard solution of ascorbic acid at least 6 times and check
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peak retention times and response (peak height or area). Inject working
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standard solutions on a regular basis within a series of analyses. Ensure orotic
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acid and isoascorbic acid are fully resolved from ascorbic acid by injecting
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separated standard solutions of both compounds (prepared as stated for
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ascorbic acid). If not resolved, the pH of the mobile phase may be decreased to
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5.0, or the amount of acetonitrile increased.
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(c).
Calibration
.- Make single injections of working standard solutions at least at
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the beginning and the end of each analytical series. Establish the calibration
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curve (seven points) by plotting peak response (height or area) versus ascorbic
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acid concentration. Perform linear regression. Calculate the slope (S) and
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intercept (I) of the calibration curve.
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(d).
Analysis
.- Make single injections of sample solutions.
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AOAC 2012.22 (FINAL VERSION REVIEW) - JUNE 2016
FOR ERP USE ONLY
DO NOT DISTRIBUTE
AOAC OMB Meeting Book
393