Record weight to nearest 0.1 mg (S) and thimble number. Note: If test sample contains large amounts of urea salts (>5%) or soluble
car bo hy drates (>15%), glyc erol, lac tic acid, amino acid salts (>10%) or
other water-soluble components, remove by water extraction. Weigh
test por tion onto fil ter pa per, ex tract with five 20 mL por tions of wa ter,
al low ing each por tion to drain. Place fil ter pa per con tain ing washed test
por tion into thim ble and dry at 102° ± 2°C for 2 h. To fa cil i tate
fil tra tion, add 1–2 g ashed, acid-washed sand, or Celite to bot tom of
fil ter or mix in with test por tion be fore wa ter ex trac tion.