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農藥超標VS農藥殘留:檢測技術助您精準識別

時間:2018-07-18 作者(zhe):中國化工儀器 閱讀:3556

近年來(lai),隨著食(shi)品安全(quan)事故的(de)頻發(fa),人們(men)對農(nong)藥(yao)化肥(fei)的(de)使用(yong)更是到了談虎(hu)色變(bian)的(de)地步。尤其是農(nong)藥(yao)超標導致的(de)食(shi)物中(zhong)毒事件,愈發(fa)加劇了社會大眾的(de)恐(kong)慌心(xin)理。部分消費者在購買時特地選(xuan)擇有“蟲(chong)眼”瓜果蔬菜,以此(ci)來(lai)防備(bei)農(nong)藥(yao)殘留導致的(de)隱(yin)患(huan)。如果農(nong)藥(yao)當(dang)真如此(ci)令人恐(kong)懼,那么(me)其存在的(de)意義又在哪里?

其實,農(nong)藥(yao)的(de)(de)使用由來(lai)已久。早(zao)在一千多年(nian)以(yi)前,人們便(bian)利用艾草、煙堿等天然物(wu)質達(da)到去除病蟲害(hai)的(de)(de)目的(de)(de)。1939年(nian),瑞士(shi)化(hua)學家米勒(le)發現合成(cheng)的(de)(de)DDT對所有昆蟲都(dou)具有極強的(de)(de)殺傷力。尤其在幫助(zhu)作物(wu)增加產(chan)量和去除病蟲害(hai)上,DDT效果顯著,因此曾被大面積推(tui)廣,人類也(ye)由此進入(ru)化(hua)學農(nong)藥(yao)時代。這表明(ming),農(nong)藥(yao)在產(chan)生之(zhi)初(chu),是飽受贊譽和期待的(de)(de)。

人(ren)(ren)們對農(nong)(nong)(nong)藥(yao)(yao)的(de)(de)抗拒心理主要來自(zi)(zi)(zi)于(yu)以下兩個層面:其一,喝(he)農(nong)(nong)(nong)藥(yao)(yao)自(zi)(zi)(zi)殺(sha)事件屢見不鮮。尤(you)其是在農(nong)(nong)(nong)村地區經常發生(sheng)喝(he)農(nong)(nong)(nong)藥(yao)(yao)自(zi)(zi)(zi)殺(sha)事件。農(nong)(nong)(nong)藥(yao)(yao)毒(du)(du)性大,死亡率較高,因此很多人(ren)(ren)將(jiang)農(nong)(nong)(nong)藥(yao)(yao)與毒(du)(du)藥(yao)(yao)等同起來。以百草(cao)枯(ku)為例(li)(li),百草(cao)枯(ku)是一種(zhong)快速滅生(sheng)性除草(cao)劑(ji),屬于(yu)中(zhong)等毒(du)(du)性農(nong)(nong)(nong)藥(yao)(yao),但對人(ren)(ren)的(de)(de)毒(du)(du)性極(ji)(ji)大,并且至(zhi)今沒有特效的(de)(de)解毒(du)(du)藥(yao)(yao),口服中(zhong)毒(du)(du)的(de)(de)死亡率極(ji)(ji)高,被(bei)人(ren)(ren)們冠以“民間死神”的(de)(de)稱號(hao),曾引(yin)起極(ji)(ji)大的(de)(de)社會恐慌。其二則是農(nong)(nong)(nong)藥(yao)(yao)超(chao)標導致的(de)(de)安全事故頻發。根據世界(jie)衛生(sheng)組織統計(ji),全世界(jie)每年至(zhi)少發生(sheng)50萬例(li)(li)農(nong)(nong)(nong)藥(yao)(yao)中(zhong)毒(du)(du)事件,死亡超(chao)過(guo)11萬人(ren)(ren)。農(nong)(nong)(nong)藥(yao)(yao)過(guo)多殘留(liu)在果蔬中(zhong)還(huan)會導致癌癥、白(bai)血病、記憶力衰退等。

近年(nian)來,我國(guo)(guo)農(nong)(nong)藥有效成分也在(zai)(zai)陸續改(gai)進(jin)(jin)中(zhong),各種高毒(du)(du)、中(zhong)毒(du)(du)農(nong)(nong)藥也已經被(bei)陸續淘汰。我國(guo)(guo)同時還是世(shi)界上主要(yao)的(de)農(nong)(nong)藥生產國(guo)(guo)和出口國(guo)(guo)。國(guo)(guo)產農(nong)(nong)藥的(de)廣泛使用進(jin)(jin)一步表明我國(guo)(guo)的(de)農(nong)(nong)藥已經逐漸(jian)走向(xiang)綠色、生態化的(de)發展道路(lu)。而消費者對于農(nong)(nong)藥的(de)恐懼(ju)歸(gui)根結底還是在(zai)(zai)于不能很好(hao)的(de)判斷農(nong)(nong)藥殘(can)留與農(nong)(nong)藥超標之間的(de)區別。

農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)殘(can)(can)留指的(de)是(shi)(shi)(shi)(shi)在(zai)(zai)(zai)農(nong)(nong)(nong)(nong)(nong)(nong)業生(sheng)產中(zhong)施用(yong)農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)后,一部(bu)分(fen)農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)直接(jie)或間(jian)接(jie)殘(can)(can)存于(yu)谷(gu)物(wu)、蔬(shu)菜、果(guo)品、畜產品、 水(shui)產品中(zhong)以(yi)及土壤和水(shui)體中(zhong)的(de)現象。農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)超標則是(shi)(shi)(shi)(shi)指殘(can)(can)留在(zai)(zai)(zai)作物(wu)中(zhong)的(de)農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)劑量(liang)超過國家標準(zhun)范(fan)圍(wei),并且(qie)會對(dui)(dui)食用(yong)者的(de)身體產生(sheng)不同(tong)程度(du)損害的(de)現象。事(shi)實上,農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)殘(can)(can)留是(shi)(shi)(shi)(shi)使用(yong)農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)后的(de)正常現象,只要保證農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)殘(can)(can)留量(liang)在(zai)(zai)(zai)國家標準(zhun)范(fan)圍(wei)內,農(nong)(nong)(nong)(nong)(nong)(nong)產品就是(shi)(shi)(shi)(shi)安全(quan)的(de)。部(bu)分(fen)針對(dui)(dui)農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)發生(sheng)的(de)食品安全(quan)事(shi)件(jian),歸根結底是(shi)(shi)(shi)(shi)由于(yu)農(nong)(nong)(nong)(nong)(nong)(nong)藥(yao)(yao)(yao)(yao)超標。

針(zhen)對(dui)農藥殘(can)留的(de)(de)(de)檢測(ce),我國已經(jing)具(ju)備了相對(dui)成(cheng)熟的(de)(de)(de)檢測(ce)技術,無(wu)論是光譜法(fa)(fa)(fa)、酶抑(yi)制(zhi)法(fa)(fa)(fa)還是色(se)譜法(fa)(fa)(fa)等,都能(neng)對(dui)農藥殘(can)留是否超標做(zuo)出(chu)檢測(ce)。其(qi)(qi)中,色(se)譜法(fa)(fa)(fa)是通(tong)過分(fen)析物質在固定(ding)相和流動相之間的(de)(de)(de)分(fen)配系數的(de)(de)(de)不同達到(dao)分(fen)離目(mu)的(de)(de)(de),并(bing)將分(fen)析物質的(de)(de)(de)濃度轉(zhuan)換成(cheng)易被(bei)測(ce)量(liang)的(de)(de)(de)電信號,然后(hou)送到(dao)記錄儀記錄下(xia)來(lai)的(de)(de)(de)方法(fa)(fa)(fa)。光譜法(fa)(fa)(fa)則(ze)是根(gen)(gen)據有機磷農藥中的(de)(de)(de)某(mou)些官能(neng)團或水解(jie)、還原產(chan)物,與特(te)(te)殊的(de)(de)(de)顯色(se)劑(ji)在特(te)(te)定(ding)的(de)(de)(de)環境(jing)下(xia)發(fa)生(sheng)氧化、磺酸化、絡合等化學反(fan)(fan)應,產(chan)生(sheng)特(te)(te)定(ding)波長的(de)(de)(de)顏色(se)反(fan)(fan)應來(lai)進(jin)行定(ding)性或定(ding)量(liang)測(ce)定(ding)。 酶抑(yi)制(zhi)法(fa)(fa)(fa)是根(gen)(gen)據有機磷和氨基甲酸酯類農藥能(neng)抑(yi)制(zhi)昆(kun)(kun)蟲(chong)中樞(shu)和周(zhou)圍神經(jing)系統中乙酰膽堿的(de)(de)(de)活性,影響昆(kun)(kun)蟲(chong)的(de)(de)(de)正(zheng)常(chang)神經(jing)傳導(dao),使其(qi)(qi)中毒致死這(zhe)一原理(li)進(jin)行檢測(ce)的(de)(de)(de)。

除此(ci)之(zhi)外(wai),近年來興起(qi)的(de)快(kuai)速檢(jian)(jian)(jian)測(ce)(ce)(ce)技(ji)(ji)術(shu)也(ye)漸漸登(deng)上農(nong)藥(yao)檢(jian)(jian)(jian)測(ce)(ce)(ce)的(de)舞臺。傳統的(de)檢(jian)(jian)(jian)測(ce)(ce)(ce)技(ji)(ji)術(shu)成本(ben)高(gao)且(qie)對環境的(de)要求比較苛刻,因此(ci)催生(sheng)出以(yi)化學速測(ce)(ce)(ce)法、免疫分(fen)析(xi)法、活體檢(jian)(jian)(jian)測(ce)(ce)(ce)法等(deng)多種快(kuai)速農(nong)藥(yao)殘(can)留檢(jian)(jian)(jian)測(ce)(ce)(ce)技(ji)(ji)術(shu)。此(ci)外(wai),我國還依據市場需要研發(fa)了專用儀器(qi)——農(nong)藥(yao)殘(can)留快(kuai)速檢(jian)(jian)(jian)測(ce)(ce)(ce)儀,在(zai)食品安全(quan)監督(du)部門、蔬(shu)菜(cai)生(sheng)產(chan)基(ji)地、蔬(shu)菜(cai)批(pi)發(fa)基(ji)地等(deng)領域都有顯著的(de)檢(jian)(jian)(jian)測(ce)(ce)(ce)功效。

在農(nong)(nong)殘問(wen)題(ti)上,消費者需要(yao)保(bao)持理(li)智的(de)(de)心態,合理(li)對(dui)待農(nong)(nong)藥的(de)(de)使用(yong)。隨著(zhu)科學技術(shu)的(de)(de)進步,我國的(de)(de)農(nong)(nong)藥成分和使用(yong)技術(shu)不斷升級(ji),只要(yao)加(jia)強好對(dui)食品的(de)(de)生產渠道、流通領域的(de)(de)監管(guan),再輔(fu)之以先進的(de)(de)檢測技術(shu),農(nong)(nong)藥超標的(de)(de)問(wen)題(ti)就會得(de)到有(you)效(xiao)遏(e)制(zhi),人(ren)們(men)的(de)(de)正常飲食也(ye)將得(de)到有(you)力保(bao)障(zhang)。