Yes, the α-Amylase SD Assay Kit (High Sensitivity Method) (K-AMYLSD) can be used for measuring alpha-amylase in barley samples (the Amylase SD assay is more sensitive than the K-CERA).  Due to the usually higher level of higher alpha-amylase in barley grains, the only suggested alteration to the standard procedure is that 0.5 g of milled barley grain is extracted in 25 mL of extraction buffer (instead of 0.5 g extracted in 4 mL).

Product Page (K-AMYLSD)