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Part 2
Analysis of bisphenol A in biological samples [Outline]
(i) LC/MS1: Serum or urine samples cleaned up with a multimode
cartridge are analyzed by a high performance liquid
chromatograph/mass spectrometer (LC/MS) qualitatively and
quantitatively.
(ii) GC/MS2: Urine samples, cleaned up with a C18 cartridge in
acid atmosphere, trimethylsilylated, and further cleaned up with
a Florisil cartridge, are analyzed by a gas chromatograph/mass
spectrometer (GC/MS) qualitatively and quantitatively.
[Reagents]
Confirm by chromatography that all the reagents present no
problem in bisphenol A (BPA) analysis.
(i) Standard samples: Environmental analysis grade BPA and
BPA-d16, and 13C-BPA supplied by Cambridge Isotope.
(ii) Standard BPA solution: Place 100 mg standard BPA in a
100-ml measuring flask, and dissolve by adding methanol to
obtain a concentrated standard solution of 1000Ęg/ml. Prepare
appropriate standard solutions by diluting the concentrated
standard solution.
(iii) Internal standard solution: Place 10 mg BPA-d16 (for
LC/MS) or 18C-BPA3 (for GC/MS) in a 50-ml measuring flask, and
dissolve by adding methanol to obtain a concentrated standard
solution of 2000 Ęg/ml. Add the internal standard solution to
the standard and sample solutions to a temporary concentration
and analyze by LC/MS or GC/MS.
(iv) Ŕ-Glucuronidase: A solution of at least 100,000 units/ml.
(v) Cartridges for purification: A multimode cartridge (500 mg)4
and a C18 cartridge (500 mg)5. Wash the cartridge with 10 ml
methanol and then 5 ml water before use. Wash the Florisil
cartridge (500 mg)6 with 5 ml n-hexane before use.
(vi) BSTFA7: Environmental analysis grade.
(vii) Pure water: Milli-Q water hardly contaminated by BPA.
Other reagents should be of the special grade or HPLC grade8.
[Tools]
Test the tools for sampling and sample preparation8 beforehand
for material or leaching, and choose ones with as little BPA
release as possible. Heat glassware to 350 for at least two
hours, let cool down in a place free from BPA contamination from
the environment, and wash with acetone immediately before use. |