取粮食样品（100.00 g）置于磷化氢释出装置中，使其与1.0 mol·L^-1硫酸溶液10.0 mL和水150 mL，在沸水浴中反应30 min，所产生的PH₃气体连续吸收在分别盛有3.3 g·L^-1高锰酸钾溶液5.0 mL和1.0 mol·L^-1硫酸溶液0.2 mL混合吸收液的3只吸收瓶中，此时，磷被全部氧化至PO₄^3-状态。合并吸收液，滴加6%（质量分数）过氧化氢溶液至开始有褐色沉淀生成，再滴加0.5 mol·L^-1氢氧化钾溶液至生成大量黑色沉淀，从而使过量高锰酸钾沉淀分离。加水定容至50.0 mL，离心后取上清液进样，按条件进行离子色谱法测定磷量。测得磷的质量浓度（以PH₃）计在0.02~4.0 mg·L^-1内与其对应的峰面积呈线性关系，检出限（3S/N）为0.005 mg·kg^-1。方法的回收率在88.0%~93.2%之间，测定值的相对标准偏差（n=6）在1.6%~2.3%之间。

The cereal sample (100.00 g) was reacted with 10.0 mL of 1.0 mg·L^-1 H₂SO₄ solution and 150 mL of water for 30 min in the reaction flask placed in boiling water bath, and the PH₃ liberated was absorbed in 3 portions of an absorption solution containing 5.0 mL of 3.3 g·L^-1 KMnO₄ solution and 0.2 mL of 1.0 mg·L^-1 H₂SO₄ solution, placed separately in 3 gas absorption flasks connected in series. At this moment, PH₃ was oxidized to PO₄^3- by KMnO₄. Excess of the KMnO₄ was destroyed by dropwise addition of 6% (w) H₂O₂ solution until formation of dark-brown colored precipitate was observed and then 0.5 mol·L^-1 KOH solution was added until the formation of bulk of black precipitate. Water was added to make the total volume to 50.0 mL. After centrifugation, the supernatant was taken and used as sample solution for IC analysis under the prescribed conditions. Linear relationship between values of peak area and mass concentration of phosphorus (in terms of PH₃) was obtained in the range of 0.02 to 4.0 mg·L^-1, with detection limit (3S/N) of 0.005 mg·kg^-1. Results of recovery found were ranged from 88.0% to 93.2% and values of RSDs (n=6) found were ranged from 1.6% to 2.3%.