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Rapid and simultaneous determination of 25-OH-vitamin D 2 and D 3 in human serum by LC/MS/MS: Validation and uncertainty assessment Ahmet C. Gören, Gökhan Bilsel, Mine Bilsel, J. Chem. Metrl. (2007), 1:1 p:1-9. (pdf of article) Abstract: 25-OH Vitamin D3 and 25-OH Vitamin D2 were determined by rapid, simple and validated
LC/MS/MS method without using SPE and isotopic standard. The relative standard deviations (RSD) were
found to be 3.1 and 2.8 % for 25-OH Vitamin D3 and 25-OH Vitamin D2, respectively. The correlation
coefficient was grater than 0.99 for both analytes in the calibration range. The recoveries at 100 μg L-1
concentration averaged to 92 % for 25-OH vitamin D3 and 94 % for 25-OH-vitamin D2. The uncertainty of the
measurements for 25-OH vitamin D3 and for 25-OH-vitamin D2 was 7.77 % and 7.24 %, respectively. Keywords: 25-OH Vitamin D3, 25-OH Vitamin D2, LC/MS/MS, method validation, uncertainty |
| 2. | Uncertainty assessment including sampling for determination of metals in lichen samples using ICP-OES Serpil Yenisoy Karakaş, J. Chem. Metrl. (2007), 1:1 p: 10-24 (pdf of article) Abstract: The uncertainty arising from the lichen sampling, preparation and analysis was calculated according
to a new guide by Eurachem/EUROLAB/CITAC/Nordest/AMC, 2007, using the retrospective lichen data set
completed in 2000 in Turkey. ICP-OES was used to determine the elements Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn,
Na, Ni, Pb, V and Zn. The method validation studies included linearity, detection limits, precision and accuracy.
Measurement uncertainties were calculated by applying the bottom-up approach. It was observed that the largest
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