An indirect method to determine Li by 74 Ge(n,γ) 75m Ge activation reaction induced in a high purity Ge (detector) crystal by neutrons from the 7 Li(p,n) 7 Be reaction in a typical particle-induced γ-ray emission (PIGE) spectroscopy experimental set-up is described. Performed with proton beams of energies in excess of 1.88MeV, the threshold energy (E th ) of the 7 Li(p,n) 7 Be reaction, the determination involves the activity measurement of 75m Ge isotope that has a half-life of 47.7s and decays with the emission of 139keV γ-rays. Rapidity, selectivity and sensitivity down to ppm levels are the attractive features of the method. It is a suitable alternative to 7 Li(p,p′γ) 7 Li reaction based PIGE technique in the analyses of matrices that contain light elements such as Be, B, F, Na and Al in significant proportions. Interferences can arise from elements, for example V and Ti, that have E th ⩽1.88MeV for (p,n) reaction. In the case of elements such as Cu, Mo which have with E th >1.88MeV, the incident proton beam energy can be judiciously selected to avoid or minimize an interference. The method, under optimized irradiation conditions, does not entail a risk of neutron stimulated degradation of the performance of the detector. Besides analytical purposes, the measurement of the 75m Ge activity can serve as a powerful tool to monitor even low (∼25n/cm 2 s) thermal neutron fluxes.