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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)