because the NR latex has a colloidal characteristic which obstruct the penetration of light beam. Thus, in this work the possibility of sample digestion by using thermoreactor was studied. It was found that the thermoreactor coupled with using 30 gL-1 ammonium persulfate as oxidizing agent could be used for NR latex digestion before phosphate residue determination by UV-VIS spectrophotometry. The calibration graph was linear over the range of 0.1 –0.9 mgL-1(R2= 0.9999). The recovery was 98.9 ± 1.9% (0.06 mgg-1, n = 11). The limit of detection was 2.9 x 10-3 mgL-1
(n = 15) and the limit of quantitation was 9.6 x 10-3 mgL-1(n = 15)