55 / 658
Conclusion
A fast and analytically sensitive LC-MS/MS method for
quantitation of 1,25D in human plasma was developed
for clinical research laboratories. Sample preparation was
done with immunoextraction. APPI ionization was used
for its ionization specificity and sensitivity. The LLOQ of
this method was 5 pg/mL for both 1,25D
2
and 1,25D
3
.
Reference
1. He, X; Damkroger, G; Kozak, M.
Quantitative Analysis of
1,25-dihydroxyvitamin D
2
and D
3
using Immunoaffinity Extraction with
APCI-LC-MS/MS
, Thermo Fisher Scientific Application Note: 522.
Research use only. Not for use in diagnostic procedures.
1,25D
2
:
m/z
411 151
5 pg/mL
1,25D
3
:
m/z
399 151
5 pg/mL
Retention Time (min)
2.0
2.6
3.2
3.8
0
366
Intensity
(A)
1,25D
2
:
m/z
411 151
11 pg/mL
1,25D
3
:
m/z
399 151
44 pg/mL
2.0
2.6
3.2
3.8
0
1310
(B)
Retention Time (min)
Figure 3. Representative SRM chromatograms of 1,25D
2
and 1,25D
3
of the lowest calibrator in solvent (A)
and in pooled human plasma (B)