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Analysis of 4-nonylphenol
in biological samples
[Outline]
The biological sample is directly injected into a column
switching liquid chromatograph/mass spectrometer (LC/MS/(MS))1
for online pretreatment and qualitative/quantitative analysis.
This procedure is designed for analysis of 4-nonylphenol (NP) in
serum.
[Reagents]
Confirm by chromatography that all the reagents present no
problem in NP analysis.
(i) Standard NP: 4- Nonylphenol of the environmental analysis
grade (mixed2,
≥95.0%)
(ii) Preparation of standard solutions: Place 100 mg standard NP
in a 100 ml measuring flask, and add acetonitrile to 100 ml.
Dilute as appropriate.
(iii) Organic solvents: Residual pesticide analysis,
environmental analysis or HPLC grade.
(iv) Purified water: Milli-Q water or commercial distilled water
hardly contaminated by NP.
(v) Internal standard3: Use deuterated 4-(1-methyl)octylphenol
for correction by internal standard. An absolute calibration
curve may be used if recovery ratio or reproducibility presents
no difficulty.
(vi) Column for pretreatment (cleanup): Choose according to
recovery ratio and purification performance4.
(vii) Glucuronidase treatment: Add 15μl of 8-glucuronidase (89
U/ml) and 200μl of 1.0 M ammonium acetate for 1 ml serum, and
incubate at 37℃ for 3 h5.
[Tools]
Confirm beforehand that the tools used for sample preparation do
not contain NP.
Wash the tools always in the specified conditions. Heat
glassware to 200℃ for at least 2 h and let cool down in a place
where no NP contamination from the environment is expected. Wash
with acetone immediately before use.
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