Page 34 - Clinical-Medical Solution for Clinical Chemistry

Evaluation of an automated LC-MS/MS system for
analyzing hydrophilic blood metabolites

Table 1. The MRM transitions of native and stable isotope molecules of
L-valine, L-leucine, L-isoleucine, L-tyrosine, and L-phenylalanine

Precursor ion Product ion
Product name
(m/z) (m/z)
L-valine 118.1 72.15
L-tyrosine 182.1 136.1
L-isoleucine 132.1 86.2
L-leucine 132.1 86.05
L-phenylalanine 166.1 120.1
L-valine (D 8) 126.2 80.15
L-tyrosine ( C 9, N) 192.2 145.2
15
13
L-isoleucine (D 10 ) 142.25 96.15
13
L-leucine ( C 6) 138.15 91.15
L-phenylalanine (D 8 ) 174.2 128.2

Results and Discussion

The utility of the CLAM-2000 as an automatic quantitative results, including the data regarding the
pre-treatment system for analyzing hydrophilic blood Fischer ratio, obtained using the two methods were
metabolites was evaluated in the present study (Table 2). almost the same. In addition, these quantitative results
In this experiment, stable isotopes corresponding to the 5 were almost the same as those acquired by SRL. The
targeted native metabolites; i.e., L-valine, L-leucine, measurement stability of each method was also high, and
L-isoleucine, L-tyrosine, and L-phenylalanine, were used the metabolites’ RSD% values were very low (<6%).
for the quantitative analysis because the quantitative Regarding the Fisher ratio data obtained using the two
performance of MS is affected by various factors, such as methods, the associated RSD% values were <1.5%.
ion suppression, and stable isotopes are required to Regarding the metabolites except L-valine, L-leucine,
obtain detailed quantitative information about the L-isoleucine, L-tyrosine, and L-phenylalanine, the
targeted molecules. The targeted metabolites included measurement stability of the automatic method is higher
branched-chain and aromatic amino acids, and the than that of the manual method (Table 3). These results
Fischer ratio was calculated based on the quantitative suggest that the CLAM-2000 could be used for automatic
results. In a comparison between the automatic method pre-treatment during the analysis of hydrophilic blood
involving the CLAM-2000 and the manual method, the metabolites.

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