Optimization and Validation of LLE-LTP and QuEChERS Methodologies for Determining 2,4-D in Water Samples

2,4-Dichlorophenoxyacetic acid (2,4-D) has been one of the main herbicides used to control weeds, however, due to its high use it can promote episodes of environmental contamination. Therefore, this study aimed to optimize and validate the liquid-liquid extraction with low-temperature partition (LLE-LTP) and the quick, easy, cheap, effective, rugged, and safe (QuEChERS) methods for determining 2,4-D in water samples by high performance liquid chromatography with diode array detector. The recovery percentages of the two methodologies were close to 100 ± 3%, and the limits of quantification were 2.0 and 3.1 µg L-1 for LLE-LTP and QuEChERS, respectively. The methodologies were selective and presented linearity from 2.0-26.0 and 3.1-40.6 µg L-1 for LLE-LTP and QuEChERS, respectively. The LLE-LTP was better than QuEChERS due to a smaller number of steps, lower reagent consumption, higher concentration factor and a lower limit of quantification. The real samples did not reveal any environmental contamination episodes by 2,4-D.

2,4-二氯苯氧乙酸（2,4-Dichlorophenoxyacetic acid，2,4-D）是当前杂草防控的主流除草剂之一，但因其使用量居高不下，可能引发环境污染事件。为此，本研究旨在优化并验证低温分液液液萃取（liquid-liquid extraction with low-temperature partition, LLE-LTP）与快速、简便、廉价、高效、耐用且安全（quick, easy, cheap, effective, rugged, and safe, QuEChERS）两种前处理方法，结合高效液相色谱-二极管阵列检测器，用于水样中2,4-D的检测。两种方法的回收率均接近100%±3%，LLE-LTP与QuEChERS方法的定量限分别为2.0 µg L⁻¹和3.1 µg L⁻¹。两种方法均具备良好选择性，LLE-LTP的线性范围为2.0~26.0 µg L⁻¹，QuEChERS方法的线性范围为3.1~40.6 µg L⁻¹。相较于QuEChERS方法，LLE-LTP优势显著：其操作步骤更少、试剂消耗量更低、富集倍数更高且定量限更低。实际水样检测结果显示，未检出2,4-D导致的环境污染事件。