The validity of the method was well assessed, and the results are
summarized in Table 1 (details are listed in Table S2eS4 of the
Supporting Data). For all analytes, a good linearity with R2 > 0.99
was achieved. Based on visual evaluation with a signal-to-noise ratio
of about 3:1 and 10:1, the LOD and LOQ of the analytes were found to
be less than 1.3 and less than 3.8 ng, which were lower than the
existing reports (Rahim et al., 2014). The RSD values of reproducibility
were reported within the range of 0.68 and 2.45% for intraday
assays and 0.75e3.37% for inter-day assays. The average recovery
of the ten analytes ranged from 91.63% to 105.28%. The results of
stability test suggested that the tea extract sample was stable in the
experiment (RSD < 1.35%). Based on these results we concluded that
the overall analytical procedure is sensitive, precise and accurate,
which is considered suitable for determination of tea samples.