Validation testing is done on new balances (accuracy, linearity, etc.) as well as a spectrophotometer. these tests are covered by astm standard test methods. for these three instruments (a balance either an analytical or a top loader), a visible /ultraviolet spectrophotometer, and a ph meter and associated calibrating buffers for each of the three instruments, find an astm method for conducting the test. state the title of each of the test methods and the astm reference number