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Table 3 Detection and analytical methods utilized in the four participating laboratories

From: A round robin approach to the analysis of bisphenol a (BPA) in human blood samples

 

Laboratory #1

Laboratory #2

Laboratory #3

Laboratory #4

Detection method

UHPLC-MS/MS using a Shimadzu (Kyoto, Japan) Nexera UHPLC system and Shimadzu LCMS-8080 triple quadrupole tandem mass spectrometer

Agilent 1100 series HPLC (Agilent Technologies Inc.,) interfaced with an Applied Biosystems API 5500 electrospray triple-quadrupole mass spectrometer (ESI-MS/MS; Applied Biosystems).

LC-MS/MS (Agilent LC 1260- AB Sciex 5500 Triple Quadrupole)

LC-MS/MS using a Thermo Surveyor TSQ plus connected to an integrated Thermo-Accela LC system.

Blanks

Charcoal/dextran stripped human serum

Milli-Q water. Trace levels of free BPA were found in procedural blanks in some batches (0.40-0.46 for Phase 2, 0.19-0.28 for Phase 3).

Double-charcoal stripped human serum

HPLC-grade water (Fisher Scientific; cat# W5-4).

Blanks: parallel?

Yes

Yes

Yes

Yes

Blank values subtracted from environmental samples?

Yes

Yes

Not required – no contamination found in blanks

Yes

LLOQ

0.10 ng/ml (uBPA)

0.01 ng/ml (uBPA)

0.1 ng/ml (uBPA and BPA-G)

0.13 ng/ml (uBPA)

0.01 ng/ml (BPA-G)

0.05 ng/ml (BPA-G)

 

0.06 ng/ml (BPA-G)

ULOQ

50 ng/mL

 

40 ng/ml (uBPA and BPA-G)

 

Calculations for determining LLOQ, ULOQ

FDA Guidance for industry biomedical method validation

The LOD and LOQ were calculated as 3 times (3S) and 10 times (10S) of the standard deviations (S) of five replicate analyses, using the lowest calibration standard (0.01 ng/mL)

a signal that has a S/N of at least 10 and is the lowest calibrant that allows a linear regression coefficient of at least 0.95

The LOD and LOQ were calculated as 3 times (3S) and 10 times (10S) of the standard deviations (S) of three replicate analyses, using the lowest calibration standard. The means of three assays are given.

http://www.fda.gov/downloads/Drugs/Guidances/ucm070107.pdf

Standard procedure. C1 pg. 6 of Guidance

LOD

0.02 ng/ml (uBPA) 0.002 ng/ml (BPA-G)

0.003 ng/ml (uBPA) 0.02 ng/ml (BPA-G)

0.05 ng/ml (uBPA and BPA-G)

0.04 ng/ml (uBPA) 0.02 ng/ml (BPA-G)