Low-Level Immunoassay Screen for 2,4-Dichlorophenoxyacetic Acid in Apples, Grapes, Potatoes, and Oranges: Circumventing Matrix Effects
Low-Level Immunoassay Screen for 2,4-Dichlorophenoxyacetic Acid in Apples, Grapes, Potatoes, and Oranges: Circumventing Matrix Effects
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DOI：
10.1021/jf940295y
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发表时间：
1996-09
影响因子：
6.1
通讯作者：
S. Richman;S. Karthikeyan;D. A. Bennett;A. C. Chung;S. M. Lee
中科院分区：
文献类型：
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作者：
S. Richman;S. Karthikeyan;D. A. Bennett;A. C. Chung;S. M. Lee
我们已经能够规避在免疫分析数据的可变性由于基质效应的发展标准添加比方法。使用市售的（Ohmicron）免疫测定法，该技术用于筛选苹果、葡萄、橙子、桃子和土豆中2,4-二氯苯氧乙酸(2,4- d)≥10 ppb。为了补偿在0.5 g产品/mL时观察到的基质效应，将标准品添加到每个样品提取物的等分液中并与之一起运行，而不需要标准曲线。各样品的表观响应随其基质的不同而不同，但加标与空白样品的比例一致（±4.6%），且加标量特征一致。对于阳性样品（≥5 ppb），该比率比阴性样品高约22%。226份样品的免疫测定与气相色谱值比较，假阳性为2 - 18.7%，阴性为2.9%。免疫分析是通过稀释乙腈萃取物来进行的，乙腈萃取物是为支持其他分析而生产的。
We have been able to circumvent the variability in immunoassay data due to matrix effects by development of a standard addition ratio method. This technique was used to develop a screen for ≥10 ppb of 2,4-dichlorophenoxyacetic acid (2,4-D) in apples, grapes, oranges, peaches, and potatoes using a commercially available (Ohmicron) immunoassay. To compensate for matrix effects observed at 0.5 g produce/mL, standard is added to an aliquot of each sample extract and run alongside it, without need of a standard curve. The apparent response of each sample varies according to its matrix, but the ratio of spiked to blank sample is consistent (±4.6%) and characteristic of the quantity spiked. For a positive sample (≥5 ppb in the assay), the ratio is ∼22% higher than for a negative sample. Comparing immunoassay with gas chromatography values for 226 samples gave 2−18.7% false positives and 2.9% negatives. The immunoassay is carried out by diluting an acetonitrile extract produced in support of other analyses with a...