Method Development and Application for Rapid Detection of the Anticholinergic Residues in Rice

稻米含抗膽鹼激性物質之快速檢定研究與應用

高靜華(Ching-Hua Kao) ； 曾佳琳(Chia-Lin Tzeng) ； 鄭允(Edward Y. Cheng)

《中華農業研究》 52卷4期 (2003/12) Pp. 324-333

https://doi.org/10.29951/JARC.200312.0007

摘要

稻米為東方人的主食，栽培時常需使用農藥以減少病蟲害，其中以在稻米上登記逾40種之氨基甲酸鹽及有機磷劑的殘毒最值得重視。此兩類殺蟲劑的毒理機制相同，均作用於動物神經系統中負責傳導的乙醯瞻鹼酯酶(AChE)，其致毒性有累加作用。本研究係嘗試以檢驗蔬果農藥殘毒之生化技術，發展稻米的殘毒快速檢測法，試驗材料為59件已具農藥殘留化學分析資料之稻米樣本，依無檢出、檢出未超量及超量違規三類分析結果，樣品各有25、28及6件。所有樣品均進行全粒及打碎兩種萃取處理，再個別以生化法檢驗之。三類樣品之全粒萃取檢驗結果顯示，乙醯膽鹼酯酶抑制值不僅與化學分析結果成正相關，且不同類別之統計差異極顯著。打碎處理的結果大致與全粒者相同，惟第三類樣品中有2件之抗乙醯膽鹼酯酶反應值下降，造成第三類與第二類樣品問的95%可信度範圍發生重疊，而差異不顯著。初步結果顯示，以高感度的乙醯瞻鹼酯酶快速檢測稻米中所含抗膽鹼物質（即氨基甲酸鹽及有機磷劑之殘毒）時，全粒萃取的檢驗可信度甚高，測試中也確認稻穀不含干擾生化檢驗成分。快速檢驗採用不同檢出標準之風險評估顯示，檢出標準由60%抑制率調降為50%及40%時，違規樣品的檢出率由50%上升至66.7%及88.3%，合格樣品之偽陰性由5.5%下降至3.9%及2.1%，檢出樣品中仍低於容許量者則由40%上升至50%及58%。稻米殘毒的快速檢驗並非用以取代現行之檢驗法，但對於提昇稻米品質安全有諸多用途，如：(1)用於辨別有機米之真偽；(2)評估不同地區、不同期作或不同年度稻米之相對安全性；(3)可提供多種農藥殘留時之總毒性數據，符合美國最新FQPA法案之要求；(4)能在有限經費下迅速檢驗成百上千件樣品。利用以上優點可全面評鑑全國水稻之安全品質，透視並改進水稻用藥問題。

關鍵字

農藥殘毒快速檢驗 ； 稻米 ； 有機磷劑 ； 氨基甲酸鹽劑 ； 乙醯膽鹼酯酶

並列摘要

Among several pesticides registered for the protection of rice crop in Taiwan, more than 40 organophosphorus and carbamate insecticides have caused concern due to their residues in harvested rice. Although chemical analysis of residues has been applied to rice, a rapid method to detect harmful levels of pesticide residues will be helpful before residue-contaminated rice is stored, processed or marketed. The residues most commonly detected in rice are those of anticholinergic agents such as, methamidophos, acephate, ethion, pirimiphos-methyl, carbofuran, carbaryl, methomyl, and BPMC. A rapid and highly sensitive acetylcholinesterase test, the rapid bioassay of pesticide residues (RBPR), that has currently been used to detect residues of organophosphate and carbamate insecticides in fruits and vegetables, was modified and tested on three groups of rice samples with known quantities of pesticide residues. Twenty-five samples, classified as group Ⅰ, had no pesticide residues; 28 samples, classified as group Ⅱ, contained organophosphorus and carbamate residues under the tolerance level; and 6 samples, classified as group Ⅲ, contained residues of above-mentioned insecticides above tolerance level. All 59 samples, extracted by whole grain extraction or freshly ground powder extraction, were tested for their anticholinergic activity. The whole grain extraction showed group Ⅰ samples to have average acetylcholinesterase inhibition of merely 6.7%; group Ⅱ, 27.6%; while group Ⅲ, 60.2%. The 95% confidence range of the means of group Ⅰ, Ⅱ, and Ⅲ were statistically separable and ranged from 1.8-11.6%, 20.0-35.3%, and 41.2-79.1%, respectively. The acetylcholinesterase inhibition correlated positively with the chemical analysis of organophosphorus and carbamate residues. In extraction of ground rice, two samples in group Ⅲ varied considerably resulting in overlapping of 95% confidence ranges of group Ⅱ and Ⅲ. The study indicated that the acetylcholinesterase test is sensitive enough to detect the residues of insecticide in rice without interference of plant chemicals in rice, and it is quantitatively correlated to chemical analysis of insecticide residues. Between two extraction methods, the whole grain treatment is preferred over rice powder method. In a hypothetic analysis of 59 samples, with detection threshold set at 60%, 50%, and 40 % acetylcholinesterase Rapid detection of anti-ch-olinergic residues in rice 325 inhibition, the correct detection rate for viotation were 50.0%, 66.7%, and 88.3%, respectivety. The detection of false negatives, decreased to 5.5%, 3.9%, and 2.1%, white unnecessary rejection rate increased from 40%, 50%, and 58%, respectively. The acetytcholinesterase inhibition test can be used effectively in (1) verification of organic rice, (2) comparison of safety of rice from different regions, seasons and year, (3) providing indexes of totat toxicity of organophosphorus and carbamate insecticide residues to fit the requirement of FQPA. The reliability, economy, time saving, and user-friendly characteristics of RBPR will facilitate screening of larger number of rice samples within a very short period for gathering basic safety information.

並列關鍵字

RBPR ； Rice ； Organophosphorus insecticides ； Carbamate insecticides ； Acetylcholinesterase