Comparison of analytical methods for extraction of chloride from plant tissue using36Cl as tracer

Eleven published and unpublished methods for extraction of chloride from plant tissue were compared, using a homogeneous sample of dried, ground maize leaves previously labelled with³⁶Cl. The most effective method of extraction of Cl^–, estimated by liquid scintillation counting of³⁶Cl, was with hot water. However, six other methods, including either cold water extraction, or dry-ashing at 500°C of plant material previously treated to give an alkaline pH, gave³⁶Cl values that were not statistically different from that obtained with hot water extraction. The lowest estimates of³⁶Cl content were obtained either by wet digestion in nitric/acetic acid or by dry-ashing following Mg(NO₃)₂ treatment of the plant material.