温度、pH对水体中柠檬醛消除的影响

Effects of Temperature and pH on the Elimination of Citral in Water

采用超高效液相色谱法（UPLC）测定初始浓度为8μL/L的柠檬醛在水中受温度、pH因子影响的消除规律。结果表明：在常温25℃、pH6.5蒸馏水中柠檬醛的浓度与时间成负相关，其直线回归方程为：y = -0.0447x ＋ 7.29，R2 = 0.9687；半衰期（t1/2）为73.60h,在水中完全降解的理论值为163.08h。在0～30℃水温范围内，柠檬醛平均消除速率为V30℃〉V 20℃〉V 10℃〉V 0℃，30℃水中柠檬醛的半衰期相对最短。在pH5.0～10.0水体中柠檬醛平均消除速率随pH升高而减小，即VpH5.0〉VpH6.0〉VpH7.0〉VpH8.0〉VpH9.0〉VpH10.0,而在pH11.0水中柠檬醛消除速率反而增大（VpH6.0〉VpH11.0〉VpH7.0），说明柠檬醛在酸性和强碱性条件下不稳定。

The effects of temperature and PH on the elimination of citral （the initial concentration 8μL/L） in water were determined using UPLC method. The results showed that the concentration of citral was negatively related to response time at the temperature of 25℃ and pH6.5, the linear regression equation was y = -0.0447x ＋ 7.29 and the regression coefficient was 0.9687. Its half-life was 73.60 hours and the theoretical value for citral completely dissolved in water was 163.08 hours. In the temperature range of 0～30℃, the average elimination rate of citral increased with the increase of temperature, i.e., V30℃〉V 20℃〉V 10℃〉V 0℃.The half-life of citral in 30℃ water was relatively the shortest. On the contrary, the average elimination rate of citral was inversely related to different pH （5.0～10.0）, i.e., V（pH5.0）〉V（pH6.0）〉V（pH7.0）〉V（pH8.0）〉V（pH9.0）〉V（pH10.0. However, the elimination rate in pH11.0 was relatively fast. In other words, citral was unstable under the acid and strong alkalinity condition.