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摘 要:研究了過硫酸鉀質(zhì)量及前期處理?xiàng)l件對(duì)水中總氮測(cè)定的影響。在常壓及水浴92℃下， K2S2O8的吸光度會(huì)隨著加熱時(shí)間的延長(zhǎng)而增大，其原因尚不清楚。在高壓及133℃消解條件下， K2S2O8的吸光度隨時(shí)間的延長(zhǎng)而降低，反應(yīng)到1個(gè)小時(shí)基本穩(wěn)定。在高壓及133℃消解條件下，尿素的分解率隨著時(shí)間的延長(zhǎng)增大，達(dá)到1.5h分解達(dá)到穩(wěn)定。高溫高壓下，10g/L的尿素溶液在3.5h時(shí)的分解出現(xiàn)劇增，此前則變化不明顯，3.5h后又保持穩(wěn)定。在高壓高溫及133℃，過硫酸鉀對(duì)尿素的氧化程度，隨著加熱時(shí)間的延長(zhǎng)而增大，1.0h達(dá)到穩(wěn)定態(tài)，氧化速度顯著高于沒有K2S2O8的情況。硝酸根標(biāo)準(zhǔn)溶液-吸光度具有良好的線性關(guān)系，線性方程如下：A=0.2317x + 0.1577, r=0.9852；總氮含量測(cè)定的前處理?xiàng)l件為：133℃高，在高壓消解罐中，反應(yīng)時(shí)間1.0h。 關(guān)鍵詞：總氮；紫外分光光度法；過硫酸鉀；分解率；高溫高壓
ABSTRACT:The influence of K2S2O8 quality and pre-treatment of samples on total nitrogen was studied. At ordinary pressure the absorption of alkaline K2S2O8 solution increased with time increased at 92℃ and the reason remained unclear. But the absorption decreased with time increased at high pressure , at 133℃, and it remained the constant nearly after 1.0 hour. Decompose of containing K2S2O8 urea increased clearly at short time than not containing K2S2O8. A Mutation phenomenon of decompose of Urea was observed at different time in the solution, and decompose of 10g/L of urea solution closed completely at high temperature and high pressure. Linear relationship of absorption to nitrate ion concentration was good, equation of linear regression as: A=0.2317x + 0.1577, r = 0.9852. The pretreatment conditions of containing nitrogen sample are the following: 133℃, 1.5 hours, reaction in the Digestion high-pressure tank. Keywords: total nitrogen, ultraviolet spectrophotometry , potassium sulfate oxidation , decomposition rate , high pressure and temperature |
