Page 52 - Clinical-Medical Solution for Clinical Chemistry

Integration of amino acid, acylcarnitine and steroids
analysis in single FIA/LC-MS/MS platform

DBS samples (d = 5mm) were placed in 96-well plates, ultrasonic bath for 30 min. Samples were measured using
and AAs, ACs and steroids were extracted with 180 L of a Nexera UHPLC system coupled to LCMS-8050 triple
80% acetonitrile-water solution consists of the known quadrupole mass spectrometer (Shimadzu Corporation,
concentrations of stable isotope labeled standards of each Japan).
compounds. The extraction were performed in an

Result

DBS provides a number of advantages, for examples, a using the combination of Nexera MP and LCMS-8040
less invasive and much simpler sample collection (Shimadzu Corporation, Japan). In addition to that, we
method rather than venipuncture technique. independently developed a method for steroids in DBS.
Furthermore, it provides you simpler storage and Steroids were separated on a Phenomenex kinetex
transportation as well as it can lower the infection risk XB-C18 (50x2mm, 2.6 m) at a column temperature of
of various pathogens, and requires a smaller blood 40 °C for 5 min.
volume. To date, DBS-LC-MS/MS has emerged as an In this study, we present a strategy for performing AAs,
important method for quantitative analysis of small ACs and steroids analysis within a single LC/MS/MS
molecules. platform. AAs, ACs and steroids were extracted from
Previously we developed an innovative AAs and ACs only one dried blood spot. This system enables to
screening method makes it possible to inject just 1 µl automatically analyze 7 min in all target analytes in 2
of sample and successfully reduce analytical run time as injections.
fast as 74 seconds (conventional method >120 sec.)

B conc. (%) Flow rate (mL/min)
100 90 90 1.0
Injection
0.7 for steroids
50 50 55
50 0.5
Injection 0.3
for AAs, ACs
0.13
0 0
0 0.5 1.0 1.5 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
1 min min 4 min min
Analysis of wash equilibration Analysis of steroids wash
AAs and ACs
valve valve
switching switching

Figure 2 Time Program of amino acids, acylcarnitines and steroids analysis

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