Auto-sample carryover was assessed by ULOQ
and LLOQ levels to ensure that it did not affect the accuracy and precision.
Table 3 shows the stability at 4[degrees]C of a calibration standard prepared at ULOQ
and of human plasma after extraction with procedure (A).
The autosampler carryover results showed minimal carryover of analyte, <0.12% of LLOQ area in the extracted blank sample after injection of ULOQ
sample for the analytes.
The overall recovery of SF and DC from spiked human plasma was determined at the LLOQ, low, medium, high QC samples, and ULOQ
. The ratio of the peak area response of extracted QC samples for SF or DC to that of the IS was compared to that of unextracted standards obtained by injecting the corresponding concentration of DC and IS in the mobile phase and analyzed in triplicate.
LLoQ and ULoQ
were defined for each analyte as the lowest concentration at which the imprecision (%CV) was <20% (LLoQ) or <15% (ULoQ
), with the measured concentration within [+ or-]20% of the nominal value.
QC > ULOQ
(upper limit of quantification) samples were diluted 5 and 20 times in the human plasma.
Lot IL-1[beta] TNF-[alpha] Concen- CV% Concen- CV% tration, tration, ng/L ng/L 1488 BD 366480 5311755 <15.6 -- <15.6 -- 1488 Monoject 320751 312120 <15.6 -- <15.6 -- 1488 BD 367874 5339582 2842 10.1 2309 5.0 1488 BD 367874 5339582 2351 19.5 2239 18.7 1492 BD 366480 5311755 <15.6 -- <15.6 -- 1492 Monoject 320751 312120 <15.6 -- <15.6 -- 1492 BD 367874 5339582 8174 4.1 2592 12.5 1492 BD 367874 5339582 Above -- 3386 14.8 ULOQ
(a) Whole blood from 2 donors was collected into BD plastic and glass [Na.sup.+]-heparin Vacutainer tubes and plastic Monoject collection tubes and allowed to incubate for 6 h.
We defined an upper limit of quantification (ULOQ
) as the value below which the percentage recovery was 80%-120% and the CV was <25%.
The highest calibrator (100 [micro]g/kg) defined the upper limit of quantification (UloQ
) for all of the analytes.
To determine the lower and upper limit of quantification (LLOQ and ULOQ
), we analyzed freshly spiked PBS (0.5, 1.0, 2.0, 100, 150, 200, 400 ng/L) in triplicate in each run, in 3 runs and 3 days, without the dialysis step.
The program included assessment of selectivity, linear range, LOD, lower limit of quantification (LLOQ), upper limit of quantification (ULOQ
), precision, absolute recovery, freezing/ thawing stability, and stability at room temperature.
Extraction recoveries were determined in triplicate at 3 concentrations for all compounds studied: the lower limit of quantification (LLOQ) was 0.02 or 0.05 [micro]g/L, depending on the molecule; the upper limit of quantification (ULOQ
) was 50 [micro]g/L; and the intermediate limit was 2 [micro]g/L.