Flow injection mass spectrometry (FI-MS) is widely employed for high-throughput metabolome analysis, yet the absence of prior separation leads to significant matrix effects, thereby limiting the metabolome coverage. In this study, we introduce a novel photosensitive MS probe, iTASO-ONH2, integrated with FI-MS to establish a high-throughput strategy for submetabolome analyses. The iTASO probe features a conjugated-imino sulfonate moiety for efficient photolysis under 365 nm irradiation and a reactive group for selective metabolite labeling. The iTASO-ONH2 probe effectively and selectively labels carbonyl compounds, forming highly stable labeled products. Upon UV exposure, the labeled products rapidly release sulfonic acid-containing photolysis products, detectable with high sensitivity in ESI-negative mode and low matrix effect, offering femtomole-level detection sensitivity. The iTASO-ONH2-based FI-MS strategy was applied to fecal samples from chronic sleep-deprived and control mice, revealing 192 potential carbonyl compounds of which 37 exhibited significant alterations. Additionally, three other photosensitive probes─iTASO-NH2, iTASO-NHS, and iTASO-MAL─were synthesized to selectively label carboxyl, amino, and thiol metabolites, respectively, underscoring the versatility of the iTASO-based FI-MS strategy for submetabolomic analysis across diverse metabolite classes.