Time-resolved laser-induced breakdown spectroscopy (LIBS) has been used as an analytical chemistry technique suitable for water analysis. Optical breakdown on the surface of water solutions was generated by the femtosecond Ti:Sa laser with the following parameters: central wavelength - 800 nm, pulse width - 60 fs, pulse energy - 1 mJ, repetition rate 50 Hz, 166 Hz, 250 Hz, 500 Hz, 1000 Hz. The limit of detection (LOD) for Mg I (285.2 nm), Mn I (403 nm, 403.3 nm), Pb I (283.3 nm), Sr I (460.7 nm) was experimentally investigated depending on the laser pulse repetition rate by the time resolved femtosecond LIBS. The best LODs for Mg I - 0.058 mg/kg, Mn I - 0.025 mg/kg, Pb I - 0.711 mg/kg, Sr I - 4.69x10-3 mg/kg water solutions were obtained for 166 Hz repetition rate.
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