Light Filth in Pepper
A. Light Filth
Weigh 50 g. test portion (or use floated material from B before ignition) into 400 ml beaker and add enough hot H2O (55-70 องศา) to make thin slurry onto No.230 sieve, 945.74B, and wash residue with forceful stream of hot H2O,using aerator,945.75B,until effluent is clear .
Wash sieve residue with Ca 100 ml. isopropanoland let drian.Transfer residue frome sieve with 40% isopropanol in to 2 L trap flask. Dilute to 800 ml with 40% isopropanol.Bring to rolling boil with magnetic stirring.Cool to room temperature in H2O bath Add 40 ml flotation liquid,945.75C.and stir magnetically 3 min,970.66B.Let oil phase separate 5 min and then fill Flask with 40% isopropanol by letting liquid flow down stirring rod.Let stand 20 min,with gentle stirring at 5 min intervals,and trap off.Repeat trapping with 20 ml flotation liquid;stir gently after addition to avoid disturbing bottom layer.Let stand 10 min and trap off.Filter noto ruled paper and examine microscopically.
Reference : JAOAC55,83(1972).
B.Heavy Filth and Sand (Ground Black and White Pepper)
Weight 50 g test portion into 600 ml beaker.Add 400 ml CCL4 and let beaker stand มากกว่าหรือเท่ากับ 1 ชม. With occasional stirring.Decant pepper and solvent on to 15 cm paper Bunchner,leaving heavy residue of sand and soil in beaker.Repeat decantation with CCl4 if necessary to secure practically compete separation of spice materials from any heavy residue .Transfer residue from beaker to ashless paper and examine for filth.If there is appreciable residue,place paper in weighed crucible,ignite,and weigh sand and soil.