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Melamine ndi chinthu chodetsa chakudya chomwe chimadziwika kuti chimapezeka m'magulu ena a chakudya mwangozi komanso mwadala. Cholinga cha kafukufukuyu chinali kutsimikizira kuzindikira ndi kuyeza kwa melamine mu mkaka wa ana ndi ufa wa mkaka. Zitsanzo zonse 40 za chakudya zomwe zimapezeka m'masitolo, kuphatikizapo mkaka wa ana ndi ufa wa mkaka, zochokera m'madera osiyanasiyana a Iran zinasanthulidwa. Kuchuluka kwa melamine m'zitsanzozo kunapezeka pogwiritsa ntchito njira yamadzimadzi yogwira ntchito bwino kwambiri ya chromatography-ultraviolet (HPLC-UV). Kapangidwe ka calibration curve (R2 = 0.9925) kanapangidwa kuti apeze melamine pakati pa 0.1–1.2 μg mL−1. Malire a kuyeza ndi kuzindikira anali 1 μg mL−1 ndi 3 μg mL−1, motsatana. Melamine inayesedwa mu mkaka wa ana ndi ufa wa mkaka ndipo zotsatira zake zinasonyeza kuti kuchuluka kwa melamine mu mkaka wa ana ndi ufa wa mkaka kunali 0.001–0.095 mg kg−1 ndi 0.001–0.004 mg kg−1, motsatana. Mfundo zimenezi zikugwirizana ndi malamulo a EU ndi Codex Alimentarius. Ndikofunikira kudziwa kuti kumwa mkaka ndi melamine yochepa sikuika pachiwopsezo chachikulu pa thanzi la ogula. Izi zikuthandizidwanso ndi zotsatira za kuwunika zoopsa.
Melamine ndi mankhwala achilengedwe okhala ndi formula ya molekyulu C3H6N6, yochokera ku cyanamide. Ili ndi kusungunuka kochepa kwambiri m'madzi ndipo ndi pafupifupi 66% ya nayitrogeni. Melamine ndi mankhwala omwe amagwiritsidwa ntchito kwambiri m'mafakitale omwe amagwiritsidwa ntchito mosiyanasiyana popanga mapulasitiki, feteleza, ndi zida zopangira chakudya (kuphatikizapo ma CD ndi ziwiya zakukhitchini)1,2. Melamine imagwiritsidwanso ntchito ngati chonyamulira mankhwala pochiza matenda. Kuchuluka kwa nayitrogeni mu melamine kungayambitse kugwiritsa ntchito molakwika mankhwalawa ndikupatsa mamolekyu a mapuloteni ku zosakaniza za chakudya3,4. Chifukwa chake, kuwonjezera melamine muzakudya, kuphatikiza mkaka, kumawonjezera kuchuluka kwa nayitrogeni. Chifukwa chake, zidaganiziridwa molakwika kuti kuchuluka kwa mapuloteni mu mkaka kunali kokwera kuposa momwe kunalili.
Pa gramu iliyonse ya melamine yowonjezeredwa, kuchuluka kwa mapuloteni muzakudya kudzawonjezeka ndi 0.4%. Komabe, melamine imasungunuka kwambiri m'madzi ndipo ingayambitse mavuto aakulu. Kuwonjezera magalamu 1.3 a melamine ku zinthu zamadzimadzi monga mkaka kungapangitse kuchuluka kwa mapuloteni a mkaka ndi 30%5,6. Ngakhale melamine imawonjezeredwa ku zakudya za nyama komanso anthu kuti iwonjezere kuchuluka kwa mapuloteni7, Codex Alimentarius Commission (CAC) ndi akuluakulu aboma sanavomereze melamine ngati chowonjezera cha chakudya ndipo adalemba kuti ndi yoopsa ngati itamezedwa, kupumidwa, kapena kuyamwa kudzera pakhungu. Mu 2012, bungwe la World Health Organization (WHO) International Agency for Research on Cancer linalemba melamine ngati khansa ya Class 2B chifukwa ingakhale yovulaza thanzi la anthu8. Kupezeka kwa melamine kwa nthawi yayitali kungayambitse khansa kapena kuwonongeka kwa impso2. Melamine mu chakudya imatha kusakanikirana ndi cyanuric acid kuti ipange makristalo achikasu osasungunuka m'madzi omwe angayambitse kuwonongeka kwa minofu ya impso ndi chikhodzodzo, komanso khansa ya mkodzo ndi kuchepa thupi9,10. Zingayambitse poizoni wa chakudya mwachangu ndipo, zikachuluka kwambiri, imfa, makamaka mwa makanda ndi ana aang'ono.11 Bungwe la World Health Organization (WHO) lakhazikitsanso kuchuluka kwa melamine tsiku lililonse (TDI) kwa anthu pa 0.2 mg/kg kulemera kwa thupi patsiku kutengera malangizo a CAC.12 Bungwe la US Food and Drug Administration (US FDA) lakhazikitsa kuchuluka kwa zotsalira za melamine pa 1 mg/kg mu fomula ya makanda ndi 2.5 mg/kg mu zakudya zina.2,7 Mu Seputembala 2008, zidanenedwa kuti opanga angapo opanga mkaka wa makanda m'nyumba adawonjezera melamine mu ufa wa mkaka kuti awonjezere kuchuluka kwa mapuloteni muzinthu zawo, zomwe zidapangitsa kuti ufa wa mkaka ukhale poizoni ndikuyambitsa vuto la poizoni wa melamine mdziko lonse lomwe lidadwalitsa ana opitilira 294,000 ndikugoneka m'chipatala anthu opitilira 50,000.13
Kuyamwitsa sikungatheke nthawi zonse chifukwa cha zinthu zosiyanasiyana monga mavuto a moyo wa m'mizinda, matenda a mayi kapena mwana, zomwe zimapangitsa kuti makanda azigwiritsa ntchito mkaka wophikidwa podyetsa makanda. Zotsatira zake, mafakitale akhazikitsidwa kuti apange mkaka wophikidwa wa makanda womwe uli pafupi kwambiri ndi mkaka wa m'mawere mu kapangidwe kake14. Mkaka wophikidwa wa makanda womwe umagulitsidwa pamsika nthawi zambiri umapangidwa kuchokera ku mkaka wa ng'ombe ndipo nthawi zambiri umapangidwa ndi mafuta osakaniza, mapuloteni, chakudya, mavitamini, mchere ndi zinthu zina. Kuti ukhale pafupi ndi mkaka wa m'mawere, mapuloteni ndi mafuta a mkakawo amasiyana, ndipo kutengera mtundu wa mkaka, amawonjezeredwa ndi zinthu monga mavitamini ndi mchere monga chitsulo15. Popeza makanda ndi gulu lomvera chisoni ndipo pali chiopsezo cha poizoni, chitetezo cha kumwa ufa wa mkaka ndichofunika kwambiri pa thanzi. Pambuyo pa mlandu wa poizoni wa melamine pakati pa makanda aku China, mayiko padziko lonse lapansi ayang'anitsitsa nkhaniyi, ndipo chidwi cha dera lino chawonjezekanso. Chifukwa chake, ndikofunikira kwambiri kulimbitsa kuwongolera kupanga mkaka wophikidwa wa makanda kuti ateteze thanzi la makanda. Pali njira zosiyanasiyana zodziwira melamine mu chakudya, kuphatikizapo high-performance liquid chromatography (HPLC), electrophoresis, sensory method, spectrophotometry ndi antigen-antibody enzyme-linked immunosorbent assay16. Mu 2007, US Food and Drug Administration (FDA) idapanga ndikufalitsa njira ya HPLC yodziwira melamine ndi cyanuric acid mu chakudya, yomwe ndi njira yothandiza kwambiri yodziwira kuchuluka kwa melamine17.
Kuchuluka kwa melamine mu mkaka wa ana woyezedwa pogwiritsa ntchito njira yatsopano ya infrared spectroscopy kunali pakati pa 0.33 ndi 0.96 milligrams pa kilogalamu (mg kg-1). 18 Kafukufuku ku Sri Lanka adapeza kuti kuchuluka kwa melamine mu ufa wa mkaka wonse kunali pakati pa 0.39 ndi 0.84 mg kg-1. Kuphatikiza apo, zitsanzo za mkaka wa ana wolowetsedwa kunja zinali ndi kuchuluka kwakukulu kwa melamine, pa 0.96 ndi 0.94 mg/kg, motsatana. Kuchuluka kumeneku kuli pansi pa malire olamulidwa (1 mg/kg), koma pulogalamu yowunikira ikufunika kuti ogula atetezeke. 19
Kafukufuku wambiri wafufuza kuchuluka kwa melamine mu mafomula a ana aku Iran. Pafupifupi 65% ya zitsanzozo zinali ndi melamine, pafupifupi 0.73 mg/kg ndipo pa avareji ndi 3.63 mg/kg. Kafukufuku wina adanenanso kuti kuchuluka kwa melamine mu mafomula a ana kunali pakati pa 0.35 ndi 3.40 μg/kg, pafupifupi 1.38 μg/kg. Ponseponse, kupezeka ndi kuchuluka kwa melamine mu mafomula a ana aku Iran kwayesedwa m'maphunziro osiyanasiyana, ndipo zitsanzo zina zokhala ndi melamine zapitirira malire apamwamba omwe akhazikitsidwa ndi akuluakulu olamulira (2.5 mg/kg/chakudya).
Poganizira za kugwiritsidwa ntchito kwakukulu kwa ufa wa mkaka mwachindunji komanso mosalunjika m'makampani ogulitsa chakudya komanso kufunika kwapadera kwa mkaka wa makanda podyetsa ana, kafukufukuyu cholinga chake chinali kutsimikizira njira yodziwira melamine mu ufa wa mkaka ndi mkaka wa makanda. Ndipotu, cholinga choyamba cha kafukufukuyu chinali kupanga njira yofulumira, yosavuta komanso yolondola yodziwira kusakanizidwa kwa melamine mu mkaka wa makanda ndi ufa wa mkaka pogwiritsa ntchito high performance liquid chromatography (HPLC) ndi ultraviolet (UV) detection; Kachiwiri, cholinga cha kafukufukuyu chinali kudziwa kuchuluka kwa melamine mu mkaka wa makanda ndi ufa wa mkaka wogulitsidwa pamsika waku Iran.
Zida zomwe zimagwiritsidwa ntchito pofufuza melamine zimasiyana malinga ndi malo opangira chakudya. Njira yodalirika komanso yodalirika yowunikira HPLC-UV idagwiritsidwa ntchito poyesa zotsalira za melamine mu mkaka ndi mkaka wa ana. Zakudya zamkaka zili ndi mapuloteni ndi mafuta osiyanasiyana omwe angasokoneze muyeso wa melamine. Chifukwa chake, monga momwe Sun et al. 22 adanenera, njira yoyenera komanso yothandiza yoyeretsera ndiyofunikira musanayesere zida. Mu kafukufukuyu, tidagwiritsa ntchito zosefera za syringe zotayidwa. Mu kafukufukuyu, tidagwiritsa ntchito mzere wa C18 kulekanitsa melamine mu mkaka wa ana ndi ufa wa mkaka. Chithunzi 1 chikuwonetsa chromatogram yodziwira melamine. Kuphatikiza apo, kubwezeretsa zitsanzo zomwe zili ndi 0.1–1.2 mg/kg melamine kunali kuyambira 95% mpaka 109%, regression equation inali y = 1.2487x - 0.005 (r = 0.9925), ndipo ma values ​​​​ofanana (RSD) anali kuyambira 0.8 mpaka 2%. Deta yomwe ilipo ikuwonetsa kuti njirayo ndi yodalirika mu kuchuluka kwa anthu komwe kwaphunziridwa (Table 1). Malire a kuzindikira (LOD) ndi malire a kuchuluka kwa melamine (LOQ) anali 1 μg mL−1 ndi 3 μg mL−1, motsatana. Kuphatikiza apo, mawonekedwe a UV a melamine anali ndi gulu loyamwa pa 242 nm. Njira yodziwira ndi yodalirika, yodalirika komanso yolondola. Njirayi ingagwiritsidwe ntchito pozindikira mulingo wa melamine nthawi zonse.
Zotsatira zofananazi zafalitsidwa ndi olemba angapo. Njira ya high-performance liquid chromatography-photodiode array (HPLC) idapangidwa kuti iwunike melamine muzinthu zamkaka. Malire ochepa a kuyeza anali 340 μg kg−1 ya ufa wa mkaka ndi 280 μg kg−1 ya mkaka wa makanda pa 240 nm. Filazzi et al. (2012) adanenanso kuti melamine sinapezeke mu mkaka wa makanda ndi HPLC. Komabe, 8% ya zitsanzo za ufa wa mkaka zinali ndi melamine pamlingo wa 0.505–0.86 mg/kg. Tittlemiet et al.23 adachita kafukufuku wofanana ndipo adapeza kuchuluka kwa melamine mu mkaka wa makanda (chitsanzo nambala: 72) pogwiritsa ntchito high-performance liquid chromatography-mass spectrometry/MS (HPLC-MS/MS) kukhala pafupifupi 0.0431–0.346 mg kg−1. Mu kafukufuku wochitidwa ndi Venkatasamy et al. (2010), njira yogwiritsira ntchito mankhwala obiriwira (popanda acetonitrile) ndi reversed-phase high-performance liquid chromatography (RP-HPLC) zinagwiritsidwa ntchito poyesa melamine mu mkaka wa ana ndi mkaka. Kuchuluka kwa zitsanzo kunali kuyambira 1.0 mpaka 80 g/mL ndipo yankho linali lolunjika (r > 0.999). Njirayi inawonetsa kuchira kwa 97.2–101.2 pa kuchuluka kwa 5–40 g/mL ndipo kubwerezabwereza kunali kochepera 1.0% poyerekeza ndi kupotoka kwa muyezo. Kuphatikiza apo, LOD ndi LOQ zomwe zinawonedwa zinali 0.1 g mL−1 ndi 0.2 g mL−124, motsatana. Lutter et al. (2011) adapeza kuipitsidwa kwa melamine mu mkaka wa ng'ombe ndi mkaka wa ana pogwiritsa ntchito HPLC-UV. Kuchuluka kwa melamine kunali kuyambira < 0.2 mpaka 2.52 mg kg−1. Njira ya HPLC-UV inali 0.05 mpaka 2.5 mg kg−1 ya mkaka wa ng'ombe, 0.13 mpaka 6.25 mg kg−1 ya mkaka wa makanda wokhala ndi gawo la mapuloteni <15%, ndi 0.25 mpaka 12.5 mg kg−1 ya mkaka wa makanda wokhala ndi gawo la mapuloteni 15%. Zotsatira za LOD (ndi LOQ) zinali 0.03 mg kg−1 (0.09 mg kg−1) ya mkaka wa ng'ombe, 0.06 mg kg−1 (0.18 mg kg−1) ya mkaka wa makanda wokhala ndi mapuloteni <15%, ndi 0.12 mg kg−1 (0.36 mg kg−1) ya mkaka wa makanda wokhala ndi mapuloteni 15%, ndi chiŵerengero cha chizindikiro-ku-phokoso cha 3 ndi 1025 cha LOD ndi LOQ, motsatana. Diebes et al. (2012) adafufuza kuchuluka kwa melamine mu zitsanzo za mkaka wa makanda ndi ufa wa mkaka pogwiritsa ntchito HPLC/DMD. Mu mkaka wa makanda, milingo yotsika komanso yapamwamba kwambiri inali 9.49 mg kg−1 ndi 258 mg kg−1, motsatana. Malire ozindikira (LOD) anali 0.05 mg kg−1.
Javaid ndi anzake adanenanso kuti zotsalira za melamine mu mkaka wa makanda zinali pakati pa 0.002–2 mg kg−1 ndi Fourier transform infrared spectroscopy (FT-MIR) (LOD = 1 mg kg−1; LOQ = 3.5 mg kg−1). Rezai ndi anzake 27 adapereka njira ya HPLC-DDA (λ = 220 nm) yowerengera melamine ndipo adapeza LOQ ya 0.08 μg mL−1 ya ufa wa mkaka, womwe unali wochepa kuposa mlingo womwe unapezeka mu kafukufukuyu. Sun ndi anzake adapanga RP-HPLC-DAD yopezera melamine mu mkaka wamadzimadzi pogwiritsa ntchito solid phase extraction (SPE). Adapeza LOD ndi LOQ ya 18 ndi 60 μg kg−128, motsatana, yomwe ndi yovuta kwambiri kuposa kafukufuku wapano. Montesano ndi anzake. yatsimikizira kugwira ntchito kwa njira ya HPLC-DMD poyesa kuchuluka kwa melamine m'mapuloteni owonjezera okhala ndi malire a 0.05–3 mg/kg, yomwe inali yochepa poyerekeza ndi njira yomwe idagwiritsidwa ntchito mu kafukufukuyu29.
Mosakayikira, ma laboratories osanthula amagwira ntchito yofunika kwambiri poteteza chilengedwe mwa kuyang'anira zodetsa m'masampulu osiyanasiyana. Komabe, kugwiritsa ntchito ma reagents ambiri ndi zosungunulira panthawi yosanthula kungayambitse kupangika kwa zotsalira zoopsa. Chifukwa chake, green analytical chemistry (GAC) idapangidwa mu 2000 kuti ichepetse kapena kuthetsa zotsatira zoyipa za njira zowunikira pa ogwiritsa ntchito ndi chilengedwe26. Njira zodziwika bwino zopezera melamine kuphatikiza chromatography, electrophoresis, capillary electrophoresis, ndi enzyme-linked immunosorbent assay (ELISA) zagwiritsidwa ntchito kuzindikira melamine. Komabe, pakati pa njira zambiri zowunikira, masensa amagetsi akopeka chidwi chachikulu chifukwa cha kukhudzidwa kwawo bwino, kusankha, nthawi yowunikira mwachangu, komanso makhalidwe abwino ogwiritsa ntchito30,31. Green nanotechnology imagwiritsa ntchito njira zamoyo zopangira nanomaterials, zomwe zingachepetse kupanga zinyalala zoopsa komanso kugwiritsa ntchito mphamvu, motero kulimbikitsa kukhazikitsa njira zokhazikika. Nanocomposites, mwachitsanzo, zopangidwa kuchokera kuzinthu zosamalira chilengedwe, zitha kugwiritsidwa ntchito mu biosensors kuti zizindikire zinthu monga melamine32,33,34.
Kafukufukuyu akuwonetsa kuti solid-phase microextraction (SPME) imagwiritsidwa ntchito bwino chifukwa cha mphamvu zake zambiri komanso kukhazikika kwake poyerekeza ndi njira zachikhalidwe zochotsera. Kusamalira chilengedwe komanso kugwiritsa ntchito mphamvu bwino kwa SPME kumapangitsa kuti ikhale njira yabwino kwambiri m'malo mwa njira zachikhalidwe zochotsera mu chemistry yowunikira ndipo imapereka njira yokhazikika komanso yothandiza yokonzekera zitsanzo35.
Mu 2013, Wu ndi anzake adapanga biosensor yodziwika bwino komanso yosankha bwino ya plasmon resonance (mini-SPR) yomwe imagwiritsa ntchito kulumikizana pakati pa melamine ndi ma antibodies otsutsana ndi melamine kuti izindikire melamine mwachangu mu fomula ya ana pogwiritsa ntchito immunoassay. Biosensor ya SPR yophatikizidwa ndi immunoassay (yogwiritsa ntchito melamine-conjugated bovine serum albumin) ndi ukadaulo wosavuta kugwiritsa ntchito komanso wotsika mtengo wokhala ndi malire ozindikira a 0.02 μg mL-136 yokha.
Nasiri ndi Abbasian adagwiritsa ntchito sensa yonyamulika yokhala ndi mphamvu zambiri kuphatikiza ndi graphene oxide-chitosan composites (GOCS) kuti azindikire melamine m'masampulu ogulitsa37. Njirayi idawonetsa kusankha bwino, kulondola, komanso kuyankha. Sensa ya GOCS idawonetsa kukhudzika kwakukulu (239.1 μM−1), mzere wolunjika wa 0.01 mpaka 200 μM, nthawi yofanana ya 1.73 × 104, ndi LOD ya mpaka 10 nM. Kuphatikiza apo, kafukufuku wochitidwa ndi Chandrasekhar et al. mu 2024 adagwiritsa ntchito njira yosamalira chilengedwe komanso yotsika mtengo. Adagwiritsa ntchito chotsitsa cha peel cha papaya ngati chochepetsera kupanga zinc oxide nanoparticles (ZnO-NPs) mwanjira yosamalira chilengedwe. Pambuyo pake, njira yapadera ya micro-Raman spectroscopy idapangidwa kuti idziwe melamine mu fomula ya ana. ZnO-NPs zochokera ku zinyalala zaulimi zasonyeza kuti ndi chida chofunikira chodziwira matenda komanso ukadaulo wodalirika komanso wotsika mtengo wowunikira ndi kuzindikira melamine38.
Alizadeh et al. (2024) adagwiritsa ntchito nsanja yowunikira yachitsulo-organic (MOF) kuti adziwe melamine mu ufa wa mkaka. Kuchuluka kwa mzere ndi malire otsika a sensa, omwe adadziwika pogwiritsa ntchito 3σ/S, anali 40 mpaka 396.45 nM (yofanana ndi 25 μg kg−1 mpaka 0.25 mg kg−1) ndi 40 nM (yofanana ndi 25 μg kg−1), motsatana. Kuchuluka kumeneku kuli pansi kwambiri pamlingo wapamwamba kwambiri wa residue levels (MRLs) womwe unakhazikitsidwa kuti uzindikire melamine mu formula ya makanda (1 mg kg−1) ndi zitsanzo zina za chakudya/chakudya (2.5 mg kg−1). Sensa ya fluorescent (terbium (Tb)@NH2-MIL-253(Al)MOF) yawonetsa kulondola kwakukulu komanso kuthekera kolondola kwambiri kuposa HPLC39 pozindikira melamine mu ufa wa mkaka. Biosensors ndi nanocomposites mu green chemistry sizimangowonjezera kuthekera kozindikira komanso zimachepetsa zoopsa zachilengedwe mogwirizana ndi mfundo za chitukuko chokhazikika.
Mfundo za chemistry yobiriwira zagwiritsidwa ntchito pa njira zosiyanasiyana zodziwira melamine. Njira imodzi ndi kupanga njira yochotsera mchere wobiriwira pogwiritsa ntchito polymer yachilengedwe ya polar β-cyclodextrin yolumikizidwa ndi citric acid kuti ichotse bwino melamine 40 kuchokera ku zitsanzo monga formula ya ana ndi madzi otentha. Njira ina imagwiritsa ntchito Mannich reaction pozindikira melamine mu zitsanzo za mkaka. Njirayi ndi yotsika mtengo, yoteteza chilengedwe, komanso yolondola kwambiri yokhala ndi mzere wa 0.1–2.5 ppm ndi malire otsika ozindikira 41. Kuphatikiza apo, njira yotsika mtengo komanso yoteteza chilengedwe yodziwira kuchuluka kwa melamine mu mkaka wamadzimadzi ndi formula ya ana idapangidwa pogwiritsa ntchito Fourier transform infrared transmission spectroscopy yokhala ndi malire olondola kwambiri komanso ozindikira a 1 ppm ndi 3.5 ppm, motsatana 42. Njirazi zikuwonetsa kugwiritsa ntchito mfundo za chemistry yobiriwira popanga njira zogwira mtima komanso zokhazikika zodziwira melamine.
Kafukufuku wambiri wapereka njira zatsopano zodziwira melamine, monga kugwiritsa ntchito njira yochotsera solid-phase ndi high-performance liquid chromatography (HPLC)43, komanso njira yofulumira yopezera madzi ya high-performance liquid chromatography (HPLC), yomwe siifuna mankhwala ovuta kapena ma ion-pair reagents, motero kuchepetsa kuchuluka kwa zinyalala za mankhwala44. Njirazi sizimangopereka zotsatira zolondola pakupeza melamine mu mkaka, komanso zimagwirizana ndi mfundo za green chemistry, kuchepetsa kugwiritsa ntchito mankhwala oopsa ndikuchepetsa kuwononga chilengedwe kwa njira yowunikira.
Zitsanzo 40 za mitundu yosiyanasiyana zinayesedwa katatu, ndipo zotsatira zake zaperekedwa mu Gome 2. Kuchuluka kwa melamine mu zitsanzo za mkaka wa ana ndi ufa wa mkaka kunali pakati pa 0.001 ndi 0.004 mg/kg komanso kuyambira 0.001 mpaka 0.095 mg/kg, motsatana. Palibe kusintha kwakukulu komwe kunawonedwa pakati pa magulu atatu azaka za mkaka wa ana. Kuphatikiza apo, melamine idapezeka mu 80% ya ufa wa mkaka, koma 65% ya mkaka wa ana unali ndi melamine.
Kuchuluka kwa melamine mu ufa wa mkaka wa mafakitale kunali kwakukulu kuposa mkaka wa ana, ndipo kusiyana kwake kunali kwakukulu (p<0.05) (Chithunzi 2).
Zotsatira zomwe zapezeka zinali pansi pa malire omwe adakhazikitsidwa ndi FDA (pansi pa 1 ndi 2.5 mg/kg). Kuphatikiza apo, zotsatirazo zikugwirizana ndi malire omwe adakhazikitsidwa ndi CAC (2010) ndi EU45,46, mwachitsanzo malire ololedwa kwambiri ndi 1 mg kg-1 ya mkaka wa makanda ndi 2.5 mg kg-1 ya mkaka.
Malinga ndi kafukufuku wa 2023 wa Ghanati et al.47, kuchuluka kwa melamine m'mitundu yosiyanasiyana ya mkaka wopakidwa m'matumba ku Iran kunali kuyambira 50.7 mpaka 790 μg kg−1. Zotsatira zawo zinali pansi pa malire ovomerezeka a FDA. Zotsatira zathu ndizotsika kuposa za Shoder et al.48 ndi Rima et al.49. Shoder et al. (2010) adapeza kuti kuchuluka kwa melamine mu ufa wa mkaka (n=49) komwe kumatsimikiziridwa ndi ELISA kunali kuyambira 0.5 mpaka 5.5 mg/kg. Rima et al. adasanthula zotsalira za melamine mu ufa wa mkaka pogwiritsa ntchito fluorescence spectrophotometry ndipo adapeza kuti kuchuluka kwa melamine mu ufa wa mkaka kunali 0.72–5.76 mg/kg. Kafukufuku adachitika ku Canada mu 2011 kuti awone kuchuluka kwa melamine mu mkaka wa makanda (n=94) pogwiritsa ntchito madzi a chromatography (LC/MS). Kuchuluka kwa melamine kunapezeka kuti kuli pansi pa malire ovomerezeka (muyezo woyamba: 0.5 mg kg−1). Sizikuoneka kuti kuchuluka kwa melamine komwe kunapezeka kunali njira yogwiritsira ntchito kuonjezera kuchuluka kwa mapuloteni. Komabe, sizingafotokozedwe pogwiritsa ntchito feteleza, kusamutsa zomwe zili mu chidebe, kapena zinthu zina zofanana. Kuphatikiza apo, komwe melamine imachokera mu ufa wa mkaka womwe umatumizidwa ku Canada sikunawululidwe50.
Hassani ndi anzake anayeza kuchuluka kwa melamine mu ufa wa mkaka ndi mkaka wamadzimadzi pamsika waku Iran mu 2013 ndipo adapeza zotsatira zofanana. Zotsatira zake zinasonyeza kuti kupatula mtundu umodzi wa ufa wa mkaka ndi mkaka wamadzimadzi, zitsanzo zina zonse zinali ndi melamine, yokhala ndi milingo kuyambira 1.50 mpaka 30.32 μg g−1 mu ufa wa mkaka ndi 0.11 mpaka 1.48 μg ml−1 mu mkaka. Chodziwika bwino n'chakuti, cyanuric acid sinapezeke mu zitsanzo zilizonse, zomwe zinachepetsa kuthekera kwa poizoni wa melamine kwa ogula. 51 Kafukufuku wakale adayesa kuchuluka kwa melamine muzinthu za chokoleti zokhala ndi ufa wa mkaka. Pafupifupi 94% ya zitsanzo zochokera kunja ndi 77% ya zitsanzo zaku Iran zinali ndi melamine. Milingo ya melamine mu zitsanzo zochokera kunja inali kuyambira 0.032 mpaka 2.692 mg/kg, pomwe zomwe zinali mu zitsanzo zaku Iran zinali kuyambira 0.013 mpaka 2.600 mg/kg. Ponseponse, melamine idapezeka mu 85% ya zitsanzo, koma mtundu umodzi wokha ndi womwe unali ndi milingo yoposa malire ovomerezeka.44 Tittlemier et al. adanenanso kuti milingo ya melamine mu ufa wa mkaka kuyambira 0.00528 mpaka 0.0122 mg/kg.
Gome 3 likufotokoza mwachidule zotsatira za kuwunika zoopsa za magulu atatu azaka. Chiwopsezocho chinali chochepera 1 m'magulu onse azaka. Chifukwa chake, palibe chiopsezo cha thanzi chomwe sichimayambitsa khansa kuchokera ku melamine mu mkaka wa ana.
Kuchepa kwa kuipitsidwa kwa zinthu za mkaka kungakhale chifukwa cha kuipitsidwa kosayembekezereka panthawi yokonzekera, pomwe kuchuluka kwa kuipitsidwa kungakhale chifukwa cha kuwonjezera dala. Kuphatikiza apo, chiopsezo chonse pa thanzi la anthu chifukwa chodya zinthu za mkaka zokhala ndi melamine yochepa chimaonedwa kuti ndi chotsika. Zingatsimikizidwe kuti kudya zinthu zokhala ndi melamine yochepa chonchi sikubweretsa chiopsezo chilichonse ku thanzi la ogula52.
Poganizira kufunika koyang'anira chitetezo cha chakudya m'makampani opanga mkaka, makamaka pankhani yoteteza thanzi la anthu, ndikofunikira kwambiri kupanga ndikutsimikizira njira yowunikira ndikuyerekeza kuchuluka kwa melamine ndi zotsalira mu ufa wa mkaka ndi mkaka wa makanda. Njira yosavuta komanso yolondola ya HPLC-UV spectrophotometric idapangidwa kuti idziwe melamine mu mkaka wa makanda ndi ufa wa mkaka. Njirayi idatsimikiziridwa kuti itsimikizire kudalirika kwake komanso kulondola kwake. Malire ozindikira ndi kuwerengera a njirayi adawonetsedwa kuti ndi osavuta kuyeza kuchuluka kwa melamine mu mkaka wa makanda ndi ufa wa mkaka. Malinga ndi deta yathu, melamine idapezeka m'zitsanzo zambiri zaku Iran. Milingo yonse ya melamine yomwe idapezeka inali pansi pa malire ovomerezeka omwe adakhazikitsidwa ndi CAC, zomwe zikusonyeza kuti kumwa mitundu iyi ya mkaka sikuika pachiwopsezo thanzi la anthu.
Mankhwala onse omwe adagwiritsidwa ntchito anali a mtundu wowunikira: melamine (2,4,6-triamino-1,3,5-triazine) 99% yoyera (Sigma-Aldrich, St. Louis, MO); acetonitrile ya mtundu wa HPLC (Merck, Darmstadt, Germany); madzi oyera kwambiri (Millipore, Morfheim, France). Zosefera za sirinji zotayidwa (Chromafil Xtra PVDF-45/25, kukula kwa pore 0.45 μm, m'mimba mwake wa nembanemba 25 mm) (Macherey-Nagel, Düren, Germany).
Kusamba ndi ultrasound (Elma, Germany), centrifuge (Beckman Coulter, Krefeld, Germany) ndi HPLC (KNAUER, Germany) zinagwiritsidwa ntchito pokonzekera zitsanzozo.
Chromatograph yamadzimadzi yogwira ntchito bwino kwambiri (KNAUER, Germany) yokhala ndi chowunikira cha UV idagwiritsidwa ntchito. Mikhalidwe yowunikira ya HPLC inali motere: makina a UHPLC Ultimate okhala ndi column yowunikira ya ODS-3 C18 (4.6 mm × 250 mm, kukula kwa tinthu tating'onoting'ono 5 μm) (MZ, Germany) adagwiritsidwa ntchito. HPLC eluent (gawo loyenda) inali chisakanizo cha TFA/methanol (450:50 mL) chokhala ndi flow rate ya 1 mL min-1. Kutalika kwa nthawi yozindikira kunali 242 nm. Voliyumu ya jakisoni inali 100 μL, kutentha kwa column kunali 20 °C. Popeza nthawi yosungira mankhwala ndi yayitali (mphindi 15), jakisoni wotsatira ayenera kupangidwa patatha mphindi 25. Melamine idazindikirika poyerekeza nthawi yosungira ndi peak ya UV spectrum ya miyezo ya melamine.
Yankho lokhazikika la melamine (10 μg/mL) linakonzedwa pogwiritsa ntchito madzi ndikusungidwa mufiriji (4 °C) kutali ndi kuwala. Sakanizani yankho lokhazikika ndi gawo loyenda ndikukonzekeretsani mayankho okhazikika ogwira ntchito. Yankho lililonse lokhazikika linalowetsedwa mu HPLC kasanu ndi kawiri. Equation ya calibration 10 inawerengedwa poyesa kubwerezabwereza kwa dera lokhazikika komanso kuchuluka komwe kunatsimikizika.
Ufa wa mkaka wa ng'ombe wogulitsidwa m'masitolo (zitsanzo 20) ndi zitsanzo za mitundu yosiyanasiyana ya mkaka wa ng'ombe wopangidwa ndi mkaka wa makanda (zitsanzo 20) zinagulidwa ku masitolo akuluakulu ndi ma pharmacies aku Iran kuti azidyetsa makanda azaka zosiyanasiyana (miyezi 0-6, miyezi 6-12, ndi miyezi >12) ndikusungidwa kutentha kwa firiji (4 °C) mpaka atafufuzidwa. Kenako, 1 ± 0.01 g ya ufa wa mkaka wofanana unayesedwa ndikusakanizidwa ndi acetonitrile:madzi (50:50, v/v; 5 mL). Chosakanizacho chinasakanizidwa kwa mphindi imodzi, kenako chinasambitsidwa mu bafa la ultrasonic kwa mphindi 30, kenako chinagwedezeka kwa mphindi imodzi. Chosakanizacho chinayikidwa mu centrifuge pa 9000 × g kwa mphindi 10 kutentha kwa chipinda ndipo supernatant inasefedwa mu vial ya 2 ml autosampler pogwiritsa ntchito fyuluta ya syringe ya 0.45 μm. Kenako filtrate (250 μl) inasakanizidwa ndi madzi (750 μl) ndipo inalowetsedwa mu dongosolo la HPLC10,42.
Kuti titsimikizire njira imeneyi, tinapeza njira yopezera, kulondola, malire ozindikira (LOD), malire owerengera (LOQ), ndi kulondola pansi pa mikhalidwe yabwino kwambiri. LOD idafotokozedwa ngati kuchuluka kwa zitsanzo zokhala ndi kutalika kwapamwamba katatu kuposa kuchuluka kwa phokoso loyambira. Kumbali ina, kuchuluka kwa zitsanzo zokhala ndi kutalika kwapamwamba nthawi 10 kuposa chiŵerengero cha chizindikiro-ku-phokoso kudafotokozedwa ngati LOQ.
Yankho la chipangizocho linapezeka pogwiritsa ntchito njira yowerengera yokhala ndi mfundo zisanu ndi ziwiri. Zinthu zosiyanasiyana za melamine zinagwiritsidwa ntchito (0, 0.2, 0.3, 0.5, 0.8, 1 ndi 1.2). Kulondola kwa njira yowerengera melamine kunapezeka. Kuphatikiza apo, milingo yosiyanasiyana ya melamine inawonjezedwa ku zitsanzo zopanda kanthu. Njira yowerengera inapangidwa mwa kubaya mosalekeza 0.1–1.2 μg mL−1 ya yankho la melamine wamba mu mkaka wa ana ndi zitsanzo za mkaka wa ufa ndipo R2 yake = 0.9925. Kulondola kunayesedwa mwa kubwerezabwereza ndi kuberekanso kwa njirayo ndipo kunapezeka mwa kubaya zitsanzo pa masiku oyamba ndi atatu otsatira (m'magawo atatu). Kubwerezabwereza kwa njirayo kunayesedwa mwa kuwerengera RSD % ya kuchuluka katatu kosiyana kwa melamine yowonjezera. Maphunziro obwezeretsa anachitika kuti adziwe kulondola. Mlingo wa kuchira pogwiritsa ntchito njira yochotsera unawerengedwa pamlingo wa melamine wochuluka katatu (0.1, 1.2, 2) mu zitsanzo za mkaka wa makanda ndi mkaka wouma9,11,15.
Mlingo woyerekeza wa tsiku ndi tsiku (EDI) unayesedwa pogwiritsa ntchito njira iyi: EDI = Ci × Cc/BW.
Pamene Ci ndi kuchuluka kwa melamine, Cc ndi mkaka womwe umagwiritsidwa ntchito ndipo BW ndi kulemera kwapakati kwa ana.
Kusanthula deta kunachitika pogwiritsa ntchito SPSS 24. Kuyezetsa kwabwinobwino kunayesedwa pogwiritsa ntchito mayeso a Kolmogorov-Smirnov; deta yonse inali mayeso osagwiritsa ntchito ma parametric (p = 0). Chifukwa chake, mayeso a Kruskal-Wallis ndi mayeso a Mann-Whitney adagwiritsidwa ntchito kuti adziwe kusiyana kwakukulu pakati pa magulu.
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