Hotplate stirrer (HAMONY LMS-1003, Japan) was used for evaporation of ammonia in NR latex sample. For the sample digestion, a thermoreactor (VELP-ECO 16 COD Thermoreactor, Italy) was employed and the phosphate residuewas determined by using double beam UV-Visible spectrophotometer (V-650 Series Spectrophotometers, Japan).