The distributive universal quantifier 每 mei3 ‘every’ can function as a determinative. When it occupies DET, the nominal phrase represents each and every subset of a set that has been mentioned in the discourse or is identifiable in the environment. For instance,
mei3 yi1 ge4 tong2xue2 dou1 bi4xu1 zuo4 hao3 chong1fen4 zhun3bei4
every one CL classmate all must make complete adequate preparation
‘Every student must be well prepared.’
各ge4 ‘every, each’ function as a determinative means a set identifiable in the environment. For example,
ge4 zu3 tong2xue2 fen1tou2 xing2dong4
each group classmate separately act
‘Each group of students acts separately.’
The difference between 每 and 各 is that 每 is compatible with any numeral in NUM but 各 is only compatible with the numeral 一 yi1 ‘one’.
Shi, Dingxu. 2016. Nouns and nominal phrases. In A Reference Grammar of Chinese, eds. by Chu-Ren Huang and Dingxu Shi. Cambridge University Press.