Reaction control with the "spin manipulation technique" is demonstrated for the D/H isotopic enrichment of the spin adduct of SDS radical detected in the photoreduction of anthraquinone in a D/H-mixed micellar solution of sodium dodecylsulfate. This spin manipulation technique for the intermediate radical pair comprises two elementary spin operations : "spin inversion" to convert the spin state between T-+/-1 and T-0 and "spin locking" to lock the spin state.