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I-Melamine sisilaphazi sokudla esaziwako esingaba khona emihlobeni ethile yokudla kokubili ngephutha nangenhloso. Umnqopho waloluphenyo bekukuqinisekisa ukutholwa nokulinganisa kwe-melamine kufomula yomntwana kanye nebisi lepuyere. Inani lamasampula wokudla atholakala emabhizinisini angama-40, kufaka hlangana ifomula yomntwana kanye nebisi lepuyere, avela eendaweni ezihlukahlukeneko ze-Iran kwahlaziywa. Ukuqukethwe kwe-melamine okulinganiselweko kwamasampula kwatholwa kusetjenziswa ihlelo le-high-performance liquid chromatography-ultraviolet (HPLC-UV). Ijika lokulinganisa (R2 = 0.9925) lakhiwa ukuthola i-melamine ebangeni elingu-0.1–1.2 μg mL−1. Imikhawulo yokulinganisa nokutholwa bekuyi-1 μg mL−1 kanye ne-3 μg mL−1, ngokulandelana. I-melamine yahlolwa kufomula yabantwana kanye nebisi lepuyere begodu imiphumela yatjengisa bona amazinga we-melamine kumasampula wefomula yomntwana kanye nebisi lepuyere bekuyi-0.001–0.095 mg kg−1 kanye ne-0.001–0.004 mg kg−1, ngokulandelana. Amagugu la akhambisana nomthetho we-EU kanye ne-Codex Alimentarius. Kuqakathekile ukutjheja bona ukusetjenziswa kwemikhiqizo yobisi ene-melamine encani akubeki ingozi ekulu epilweni yabathengi. Lokhu kusekelwa nemiphumela yokuhlolwa kobungozi.
I-Melamine yi-organic compound enefomula yamamolekhyuli i-C3H6N6, evela ku-cyanamide. Inokuncibilika okuphasi khulu emanzini begodu ingaba yi-66% ye-nitrogen. I-Melamine yinto esetjenziswa khulu emabubulweni eneensetjenziswa ezinengi ezisemthethweni ekukhiqizeni amapulasitiki, amamanyolo, kanye nemitjhini yokupheka ukudla (okufaka hlangana ukupakisha ukudla kanye nezinto zasekhishini)1,2. I-melamine nayo isetjenziswa njengesithwali semithi ekwelapheni amalwelwe. Inani eliphezulu le-nitrogen ku-melamine lingadosela ekusetjenzisweni kumbi kwekhompawundi begodu kunikelwe izakhiwo zamamolekhyuli wamaphrotheyini eentweni zokudla3,4. Ngalokho-ke, ukungezelela i-melamine emikhiqizweni yokudla, okufaka hlangana imikhiqizo yobisi, kukhuphula inani le-nitrogen. Ngalokho, kwaphethwa ngokungakalungi bona amaprotheyini webisi bekaphezulu kunalokho ebegade akhona.
Ngalinye igremu ye-melamine eyengeziweko, amaphrotheyini wokudla azokukhuphuka nge-0.4%. Kodwana, i-melamine incibilika khulu emanzini begodu ingabanga umonakalo omkhulu. Ukungezelela amagremu ayi-1.3 we-melamine emikhiqizweni efana nobisi kungakhuphula amaphrotheyini webisi ngama-30%5,6. Nanyana i-melamine ifakwa ekudleni kweenlwana ngitjho nabantu ukwandisa amaphrotheyini7, i-Codex Alimentarius Commission (i-CAC) kanye neziphathimandla zesitjhaba azange zivumele i-melamine njengesengezo sokudla begodu bayifaka erhelweni njengeyingozi nangabe igwinywa, iphefumulelwa, nofana idonswa ngesikhumba. Ngo-2012, i-World Health Organization's (WHO) International Agency for Research on Cancer yafaka i-melamine njenge-Class 2B carcinogen ngombana ingaba yingozi epilweni yabantu8. Ukuvezwa isikhathi eside ku-melamine kungabanga umdlavuza nofana ukulimala kwezinso2. I-melamine ekudleni ingahlangana ne-cyanuric acid ukwakha amakristalu aphuzi angancibiliki emanzini angabangela ukulimala kwezinso nezicubu zesinya, kanye nomdlavuza wendlela yomchamo nokulahlekelwa sisindo9,10. Kungabangela ukutjhejwa kokudla okubukhali, begodu, lokha nakunengi, ukuhlongakala, khulukhulu emasaneni nasebantwaneni abancani.11 Ihlangano yezamaphilo yephasi loke (i-WHO) nayo ibeke ukudla okubekezelelekako kwe-melamine ebantwini ku-0.2 mg/kg yesisindo somzimba ngelanga ngokuya ngemihlahlandlela ye-CAC.12 I-US Food and Drug Administration (US) ibeke izinga eliphezulu le-FDA 1 mg/kg yefomula yomntwana kanye no-2.5 ​​mg/kg kwezinye ukudla.2,7 NgoNobayeni 2008, kwabikwa bona abakhiqizi abanengi befomula yomntwana bebafake i-melamine epuyereni yobisi ukwandisa amaphrotheyini emikhiqizweni yabo, okwabangela bona kube nobuthi bebisi begodu kwabanga isigameko se-melamine esakhulisa abantwana abangaphezu kwama-2004 bangeniswe esibhedlela abangaphezu kwama-50,000. 13
Ukumunyisa akwenzeki ngaso soke isikhathi ngebanga lezinto ezihlukahlukeneko ezifana nobudisi bepilo yemadorobheni, ukugula komma nofana umntwana, okwenza bona kusetjenziswe i-infant formula ukondla abantwana. Njengomphumela, amafemu asungulwe ukukhiqiza ifomula yomntwana eseduze khulu nebisi lebele ngokwakheka14. Ifomula yosana ethengiswa emakethe ivamise ukwenziwa ngebisi lenkomo begodu ivamise ukwenziwa ngehlanganisela ekhethekileko yamafutha, amaphrotheyini, ama-carbohydrate, amavithamini, amaminerali kanye nezinye iinhlanganisela. Ukuze kube seduze nebisi lebele, amaprotheyini namafutha wefomula ayahluka, begodu kuya ngomhlobo webisi, aqiniswa ngamakhompawundi afana namavithamini namaminerali afana ne-ayini15. Njengombana iinsana ziyisiqhema esibucayi begodu kunengozi yokutjhejwa, ukuphepha kokusebenzisa ipuyere yobisi kuqakathekile epilwenakho. Ngemva kwecala lokutheleleka nge-melamine hlangana nabantwana be-China, amazwe ephasini loke atjheje khulu indaba le, begodu ukuzwela kwalendawo nakho kukhuphukile. Ngalokho-ke, kuqakatheke khulu ukuqinisa ukulawulwa kokukhiqizwa kwefomula yabantwana ukwenzela ukuvikela ipilo yabantwana. Kuneendlela ezihlukahlukeneko zokuthola i-melamine ekudleni, okufaka hlangana i-high-performance liquid chromatography (HPLC), i-electrophoresis, indlela yokuzwa, i-spectrophotometry kanye ne-antigen-antibody enzyme-linked immunosorbent assay16. Ngomnyaka ka-2007, i-US Food and Drug Administration (FDA) yathuthukisa begodu yagadangisa indlela ye-HPLC yokuthola i-melamine ne-cyanuric acid ekudleni, okuyindlela ephumelela khulu yokuthola okuqukethwe kwe-melamine17.
Ukugxila kwe-melamine kufomula yabantwana okulinganiswa kusetjenziswa indlela etja ye-infrared spectroscopy kusuka ku-0.33 ukuya ku-0.96 wamamiligremu ngekhilogremu (mg kg-1). 18 Irhubhululo e-Sri Lanka lathola amazinga we-melamine ku-whole milk powder asuka ku-0.39 ukuya ku-0.84 mg kg-1. Ukungezelela, amasampula wefomula yomntwana angeniswa kwamanye amazwe anezinga eliphezulu le-melamine, ku-0.96 no-0.94 mg/kg, ngokulandelana. Amazinga la angaphasi komkhawulo olawulwako (1 mg/kg), kodwana ihlelo lokutjheja liyatlhogeka ukuphepha kwabathengi. 19
Iimfundo ezinengi zihlolisise amazinga we-melamine kumafomula wezingane ze-Iran. Amasampula angaba ma-65% bekane-melamine, ngesilinganiso esingu-0.73 mg/kg kanye nobukhulu obungu-3.63 mg/kg. Olunye ucwaningo lubike bona izinga le-melamine kufomula yabantwana belisuka ku-0.35 ukuya ku-3.40 μg/kg, ngesilinganiso esingu-1.38 μg/kg. Ngokupheleleko, ubukhona nezinga le-melamine kumafomula wezingane ze-Iran kuhloliwe eemfundweni ezihlukahlukeneko, lapho amanye amasampula ane-melamine edlula umkhawulo ophakemeko obekwe ziiphathimandla ezilawulako (2.5 mg/kg/ukudla).
Nakuqalwa ukusetjenziswa okukhulu kwebisi eliyipuyere embonini yokudla kanye nokuqakatheka okukhethekileko kwefomula yomntwana ekudleni abantwana, irhubhululo leli belihlose ukuqinisekisa indlela yokuthola i-melamine ebisi lepuyere nefomula yezingane. Kuhlekuhle, umnqopho wokuthoma waloluphenyo bekukuthuthukisa indlela yokulinganisa ekhawulezako, elula nenembileko yokuthola ukuhlanganiswa kwe-melamine ku-fomula yomntwana kanye ne-milk powder kusetjenziswa i-high performance liquid chromatography (HPLC) kanye ne-ultraviolet (UV) detection; Kwesibili, umnqopho waloluphenyo bekukuthola okuqukethwe kwe-melamine kufomula yabantwana kanye nobisi oluthengiswa emakethe ye-Iran.
Iinsetjenziswa ezisetjenziselwa ukuhlaziywa kwe-melamine ziyahluka ngokuya ngendawo yokukhiqizwa kokudla. Indlela yokuhlaziya ye-HPLC-UV ebucayi nethembekileko yasetjenziselwa ukulinganisa iinsalela ze-melamine ebisi nefomula yomntwana. Imikhiqizo yebisi inamaphrotheyini ahlukahlukeneko namafutha angaphazamisa ukulinganisa i-melamine. Ngalokho-ke, njengombana kutjhiwo ngu-Sun et al. 22, isu lokuhlanza elifaneleko nelisebenzako liyatlhogeka ngaphambi kokuhlaziywa kweensetjenziswa. Kulesi sifundo, sisebenzise izihlungi zesirinji ezilahlwayo. Esifundweni lesi, sisebenzise ikholomu ye-C18 ukuhlukanisa i-melamine kufomula yomntwana kanye nobisi lwepuyere. Umfanekiso 1 utjengisa i-chromatogram yokuthola i-melamine. Ukungezelela, ukubuyiswa kwamasampula ane-0.1–1.2 mg/kg ye-melamine bekusuka ku-95% ukuya ku-109%, i-equation yokubuyela emuva bekuyi-y = 1.2487x − 0.005 (r = 0.9925), begodu amazinga wokuphambuka okuhlobeneko (RSD) bekusuka ku-0.0% ukuya ku-28%. Idatha etholakalako itjengisa bona indlela le ithembekile ebangeni lokugxila elifundwako (Ithebula 1). Umkhawulo wokuthola (LOD) kanye nomkhawulo wokulinganisa (LOQ) we-melamine bekuyi-1 μg mL−1 kanye ne-3 μg mL−1, ngokulandelana. Ukungezelela, i-UV spectrum ye-melamine itjengise ibhendi yokumuncwa ku-242 nm. Indlela yokuthola izwela, ithembekile begodu inembile. Indlela le ingasetjenziselwa ukuthola izinga le-melamine.
Imiphumela efanako sele ivezwe batloli abanengi. Indlela ye-high-performance liquid chromatography-photodiode array (HPLC) yasungulwa ukuhlaziywa kwe-melamine emikhiqizweni yobisi. Imikhawulo ephasi yokulinganisa beyiyi-340 μg kg−1 yebisi lepuyere kanye ne-280 μg kg−1 yefomula yomntwana ku-240 nm. UFilazzi nabanye. (2012) wabika bona i-melamine azange itholakale efomula yomntwana nge-HPLC. Kodwana, i-8% yamasampula wepuyere yobisi gade ine-melamine ezingeni elingu-0.505-0.86 mg/kg. U-Tittlemiet et al.23 benza irhubhululo elifanako begodu bathola bona i-melamine equkethwe yifomula yomntwana (inombolo yesampula: 72) nge-high-performance liquid chromatography-mass spectrometry/MS (HPLC-MS/MS) bona ibe pheze ku-0.0431–0.346 mg kg−1. Esifundweni esenziwe ngu-Venkatasamy et al. (2010). Ibanga lokugxila kwesampula belisuka ku-1.0 ukuya ku-80 g/mL begodu ipendulo beyiqondile (r > 0.999). Indlela le itjengise ukubuyiselwa kwe-97.2 ukuya ku-101.2 phezu kwebanga lokugxila elingu-5 ukuya ku-40 g/mL begodu ukukhiqiza bekungaphansi kwe-1.0% yokuphambuka okujayelekileko. Ukudlula lapho, i-LOD ebonwako ne-LOQ bekuyi-0.1 g mL−1 kanye ne-0.2 g mL−124, ngokulandelana. U-Lutter nabanye. (2011) bathola ukusilaphazeka kwe-melamine ebisi lenkomo kanye nefomula yomntwana esekelwe ebisini ngokusebenzisa i-HPLC-UV. Ukugxila kwe-melamine bekusuka ku-< 0.2 ukuya ku-2.52 mg kg−1. Ububanzi bendlela ye-HPLC-UV bebuyi-0.05 ukuya ku-2.5 mg kg−1 yobisi lwenkomo, 0.13 ukuya ku-6.25 mg kg−1 yefomula yosana enengcenye yamaphrotheyini engu-<15%, kanye no-0.25 ukuya ku-12.5 mg kg−1 yefomula yomntwana enengcenye yamaprotheyini we-15%. Imiphumela ye-LOD (ne-LOQ) bekungu-0.03 mg kg−1 (0.09 mg kg−1) yobisi lwenkomo, 0.06 mg kg−1 (0.18 mg kg−1) yefomula yomntwana <15% yamaphrotheyini, kanye ne-0.12 mg kg−1 (0.36 mg kg) yefomula yomntwana engu-15% yamaphrotheyini, ukuzwa isiginali isilinganiso se-3 ne-1025 se-LOD ne-LOQ, ngokulandelana. U-Diebes et al. (2012) baphenya amazinga we-melamine kumasampula wefomula yomntwana kanye nebisi lepuyere ngokusebenzisa i-HPLC/DMD. Efomula yabantwana, amazinga aphasi naphezulu bekuyi-9.49 mg kg−1 kanye ne-258 mg kg−1, ngokulandelana. Umkhawulo wokutholwa (LOD) bekungu-0.05 mg kg−1.
U-Javaid nabanye. ibike bona iinsalela ze-melamine efomula yomntwana beziphakathi kwe-0.002–2 mg kg−1 nge-Fourier transform infrared spectroscopy (FT-MIR) (LOD = 1 mg kg−1; LOQ = 3.5 mg kg−1). U-Rezai et al.27 bahlongoza indlela ye-HPLC-DDA (λ = 220 nm) ukulinganisa i-melamine begodu bafinyelela i-LOQ ye-0.08 μg mL−1 ye-milk powder, ebegade ingaphasi kwezinga elitholwe esifundweni lesi. Ilanga nabanye. yenza i-RP-HPLC-DAD yokuthola i-melamine ebisini elimanzi ngokukhipha isigaba esiqinileko (SPE). Bathola i-LOD ne-LOQ ye-18 ne-60 μg kg−128, ngokulandelana, okubucayi ukudlula isifundo samanje. U-Montesano nabanye. iqinisekise ukusebenza kwendlela ye-HPLC-DMD yokuhlola okuqukethwe kwe-melamine kuma-supplement wamaprotheyini ngomkhawulo wokulinganisa we-0.05-3 mg/kg, ebegade ingazweli kangako kunendlela esetjenziswe esifundweni lesi29.
Ngokungangabazeki, amalabhorethri wokuhlaziya adlala indima eqakathekileko ekuvikeleni ibhoduluko ngokutjheja izinto ezisilaphazako emasampula ahlukahlukeneko. Kodwana, ukusetjenziswa kwenani elikhulu lama-reagents nama-solvents ngesikhathi sokuhlaziywa kungabangela ukwakheka kweensalela eziyingozi. Ngalokho-ke, ikhemistri yokuhlaziya eluhlaza (i-GAC) yasungulwa ngo-2000 ukwehlisa nofana ukuqeda imiphumela emimbi yeenkambiso zokuhlaziya kubasebenzisi nebhoduluko26. Iindlela ezijayelekileko zokuthola i-melamine ezifaka hlangana i-chromatography, i-electrophoresis, i-capillary electrophoresis, kanye ne-enzyme-linked immunosorbent assay (ELISA) zisetjenziselwe ukuthola i-melamine. Kodwana, hlangana neendlela ezinengi zokuthola, iinzwa ze-electrochemical zidose ukutjhejwa okukhulu ngebanga lokuzwela kwazo okuhle khulu, ukukhetha, isikhathi sokuhlaziya esirhabako, kanye neemfanelo ezisebenziseka lula30,31. Ithekhnoloji eluhlaza ye-nano isebenzisa iindlela zezinto eziphilako ukwenza ama-nanomaterials, okunganciphisa ukukhiqizwa kwemfucuza eyingozi nokusetjenziswa kwamandla, ngaleyo ndlela kukhuthaze ukusetjenziswa kwemikhuba esimemeko. Ama-nanocomposites, ngokwesibonelo, enziwe ngezinto ezingalimazi ibhoduluko, angasetjenziswa kuma-biosensors ukuthola izinto ezifana ne-melamine32,33,34.
Irhubhululo litjengisa bona ukukhipha okuncani okuqinileko (i-SPME) kusetjenziswa kuhle ngebanga lokusebenzisa amandla aphezulu nokusimama kwayo nayiqathaniswa neendlela zokukhipha ezijayelekileko. Ukuba nobungani kwebhoduluko nokusebenzisa amandla kuhle kwe-SPME kwenza bona ibe yindlela ehle khulu yokukhipha iindlela zendabuko kukhemistri yokuhlaziya begodu inikela ngendlela esimemeko nesebenzako yokulungiselela isampula35.
Ngo-2013, u-Wu et al. yenza i-biosensor ye-plasmon resonance (mini-SPR) ebucayi khulu nekhethako esebenzisa ukuhlanganiswa hlangana nama-melamine nama-anti-melamine ama-antibodies ukuthola msinyana i-melamine kufomula yomntwana ngokusebenzisa i-immunoassay. I-SPR biosensor ehlanganiswe ne-immunoassay (ngokusebenzisa i-melamine-conjugated bovine serum albumin) yithekhnoloji elula ukuyisebenzisa begodu ebiza kancani enomkhawulo wokutholwa we-0.02 μg mL-136 kwaphela.
U-Nasiri no-Abbasian basebenzise inzwa ephathekako enamandla amakhulu ngokuhlanganiswa nama-graphene oxide-chitosan composites (GOCS) ukuthola i-melamine kumasampula wokuthengisa37. Indlela le itjengise ukukhetha okuphezulu khulu, ukunemba, nokuphendula. Inzwa ye-GOCS itjengise ukuzwela okuphawulekako (239.1 μM−1), ibanga eliqondileko elingu-0.01 ukuya ku-200 μM, i-affinity constant ye-1.73 × 104, kanye ne-LOD efika ku-10 nM. Ngaphezu kwalokho, irhubhululo elenziwa ngu-Chandrasekhar et al. ngo-2024 wamukela indlela engalimazi ibhoduluko nengabiziko. Basebenzisa i-papaya peel extract njenge-ejenti yokunciphisa ukwenza ama-zinc oxide nanoparticles (ZnO-NPs) ngendlela engalimazi ibhoduluko. Ngemva kwalokho, kwakhiwa indlela ehlukileko ye-micro-Raman spectroscopy yokuthola i-melamine kufomula yosana. I-ZnO-NPs evela emfucumfucwini wezokulima itjengise amandla njengethuluzi eliqakathekileko lokuhlola kanye nobuchwepheshe obuthembekileko, obubiza kancani bokuqapha nokuthola i-melamine38.
U-Alizadeh nabanye. (2024) wasebenzisa ipulatifomu yokukhanya kwe-metal-organic framework (MOF) ezwelako khulu ukuthola i-melamine ku-milk powder. Ibanga eliqondileko kanye nomkhawulo ongaphasi wokutholwa wesensa, okunqunywe ngokusebenzisa i-3σ/S, bekungu-40 ukuya ku-396.45 nM (okulingana no-25 μg kg−1 ukuya ku-0.25 mg kg−1) kanye no-40 nM (okulingana no-25 μg kg−1), ngokulandelana. Ibanga leli lingaphasi khulu kwamazinga aphezulu weensalela (ama-MRL) abekelwe ukukhonjwa kwe-melamine kufomula yomntwana (1 mg kg−1) namanye amasampula wokudla/wokudla (2.5 mg kg−1). Inzwa yokukhanya (i-terbium (Tb)@NH2-MIL-253(Al)MOF) itjengise ukunemba okuphezulu nekghono lokulinganisa eliqondileko ukudlula i-HPLC39 ekutholeni i-melamine ku-milk powder. I-biosensors kanye nama-nanocomposites ku-green chemistry azikhulisi amakghono wokuthola kwaphela kodwana zinciphisa ubungozi bebhoduluko ngokuya ngemigomo yentuthuko esimemeko.
Imigomo yekhemistri eluhlaza isetjenziswe eendleleni ezihlukahlukeneko zokuthola i-melamine. Enye indlela kukuthuthukisa indlela yokukhipha i-microextraction eqinileko eluhlaza kusetjenziswa i-polar polymer yemvelo β-cyclodextrin ehlanganiswe ne-citric acid ukukhipha i-melamine 40 ephumelelako emasampula afana nefomula yomntwana namanzi atjhisako. Enye indlela isebenzisa ukusabela kwe-Mannich ukuthola i-melamine kumasampula webisi. Indlela le ayibizi, ayilimazi ibhoduluko, begodu inembile khulu nge-linear range ye-0.1–2.5 ppm kanye nomkhawulo ophasi wokutholakala 41. Ukudlula lapho, indlela engabiziko nengalimazi ibhoduluko yokuthola inani le-melamine ebisini elimanzi nefomula yabantwana yakhiwa kusetjenziswa i-Fourier transform transmission infrascopy enomkhawulo ophakemeko wokunemba 1 ppm kanye ne-3.5 ppm, ngokulandelana 42. Iindlela lezi zitjengisa ukusetjenziswa kwemigomo yekhemistri eluhlaza ekuthuthukisweni kweendlela ezisebenzako nezizinzileko zokuthola i-melamine.
Iimfundo ezinengi ziphakamise iindlela ezitjha zokuthola i-melamine, njengokusebenzisa ukukhipha isigaba esiqinileko kanye ne-high-performance liquid chromatography (HPLC)43, kanye ne-fast high-performance liquid chromatography (HPLC), engatlhogi ukuphathwa ngaphambilini okuyinkimbinkimbi nofana ama-ion-pair reagents, ngaleyindlela kwehlisa inani lamakhemikhali. Iindlela lezi azinikeli imiphumela enembako yokuthola i-melamine emikhiqizweni yobisi kwaphela, kodwana zihambisana nemigomo yekhemistri eluhlaza, ukwehlisa ukusetjenziswa kwamakhemikhali ayingozi begodu ukwehlisa umthelela jikelele wemvelo wendlela yokuhlaziya.
Amasampula amatjhumi amane wamabhrendi ahlukileko ahlolwa kathathu, begodu imiphumela yethulwe kuThebuli 2. Amazinga we-melamine kumasampula wefomula yomntwana kanye namasampula wepuyere yebisi asuka ku-0.001 ukuya ku-0.004 mg/kg begodu ukusuka ku-0.001 ukuya ku-0.095 mg/kg, ngokulandelana. Akukho amatjhuguluko aqakathekileko abonwa hlangana namakoro amathathu weminyaka yefomula yomntwana. Ukungezelela, i-melamine yatholakala ku-80% yepuyere yebisi, kodwana i-65% yamafomula womntwana bekancoliswe yi-melamine.
Okuqukethwe kwe-melamine ebisi lepuyere yamabubulo bekuphezulu kunefomula yomntwana, begodu umehluko bewuqakathekile (p<0.05) (Umfanekiso 2).
Imiphumela etholakeleko beyingaphasi kwemikhawulo ebekwe yi-FDA (ngaphasi kwe-1 ne-2.5 mg/kg). Ukungezelela, imiphumela ihambisana nemikhawulo ebekwe yi-CAC (2010) kanye ne-EU45,46, okutjho bona umkhawulo ophezulu ovunyelweko ngu-1 mg kg-1 wefomula yomntwana kanye no-2.5 ​​mg kg-1 wemikhiqizo yobisi.
Ngokuya kwesifundo saka-2023 esenziwa ngu-Ghanati et al.47, okuqukethwe kwe-melamine emihlobeni ehlukileko yobisi olupakishweko e-Iran bekusuka ku-50.7 ukuya ku-790 μg kg−1. Imiphumela yabo beyingaphasi komkhawulo ovunyelweko we-FDA. Imiphumela yethu iphasi kunaleyo ka-Shoder et al.48 no-Rima et al.49. UShoder et al. (2010) bathola bona amazinga we-melamine ku-milk powder (n=49) anqunywe yi-ELISA asuka ku-0.5 ukuya ku-5.5 mg/kg. U-Rima nabanye. wahlaziya iinsalela ze-melamine kubisi nge-fluorescence spectrophotometry begodu wathola bona okuqukethwe kwe-melamine ku-milk powder bekuyi-0.72–5.76 mg/kg. Irhubhululo lenziwa e-Canada ngo-2011 ukutjheja amazinga we-melamine kufomula yomntwana (n=94) kusetjenziswa i-liquid chromatography (LC/MS). Amazinga we-melamine atholakala angaphasi komkhawulo owamukelekako (izinga lokuthoma: 0.5 mg kg−1). Akunakwenzeka bona amazinga we-melamine wobuqili atholakeleko bekuliqhinga elisetjenziselwa ukwandisa okuqukethwe kwamaphrotheyini. Kodwana, angeze kwachazwa ngokusetjenziswa kwamanyolo, ukuthuthwa kwezinto eziphakathi kwesitja, nofana izinto ezifanako. Ukudlula lapho, umthombo we-melamine epuyereni yobisi engeniswa e-Canada awuzange udalulwe50.
U-Hassani nabanye. yalinganisa okuqukethwe kwe-melamine ebisi lepuyere nebisi elimanzi emakethe ye-Iran ngo-2013 begodu yathola imiphumela efanako. Imiphumela itjengise bona ngaphandle komhlobo owodwa webisi lepuyere nebisi elimanzi, woke amanye amasampula bekancoliswe yi-melamine, ngamazinga asuka ku-1.50 ukuya ku-30.32 μg g−1 ebisi lepuyere kanye no-0.11 ukuya ku-1.48 μg ml−1 ebisi. Ngokuphawulekako, i-cyanuric acid azange itholakale kiwo woke amasampula, okwenza bona kube nobuthi be-melamine ebathengini. 51 Iimfundo zangaphambilini zihlolisise ukugxila kwe-melamine emikhiqizweni yetjhokoleti enepuyere yobisi. Amasampula angaba ma-94% angeniswa ngaphandle kanye nama-77% wamasampula we-Iran bekane-melamine. Amazinga we-melamine kumasampula angeniswa ngaphandle asuka ku-0.032 ukuya ku-2.692 mg/kg, kuthi lawo kumasampula we-Iran asuka ku-0.013 ukuya ku-2.600 mg/kg. Ngokupheleleko, i-melamine yatholakala kuma-85% wamasampula, kodwana mhlobo munye kwaphela othileko onamazinga angaphezu komkhawulo ovunyelweko.44 U-Tittlemier et al. kubikwe amazinga we-melamine ku-milk powder ukusuka ku-0.00528 ukuya ku-0.0122 mg/kg.
Ithebula 3 lifingqa imiphumela yokuhlolwa kwengozi yamaqembu amathathu weminyaka. Ingozi beyingaphasi kwe-1 kiwo woke amaqembu weminyaka. Ngalokho, ayikho ingozi yezamaphilo engabangeli umdlavuza evela ku-melamine kufomula yomntwana.
Amazinga aphasi wokusilaphazeka emikhiqizweni yebisi angabangelwa kukusilaphazeka okungakahlosiweko ngesikhathi sokulungiselela, kuthi amazinga aphezulu angabangelwa kufakwa ngamabomu. Ukudlula lapho, ubungozi bepilo yabantu ngokudla imikhiqizo yobisi enamazinga aphasi we-melamine buthathwa njengaphasi. Kungaphethwa ngokuthi ukudla imikhiqizo enamazinga aphasi kangaka we-melamine akubeki ingozi epilweni yabathengi52.
Nawuqala ukuqakatheka kokulawulwa kokuphepha kokudla embonini yobisi, khulukhulu malungana nokuvikela ipilo yomphakathi, kuqakatheke khulu ukuthuthukisa nokuqinisekisa indlela yokuhlola nokumadanisa amazinga we-melamine kanye neensalela ebisi lepuyere nefomula yomntwana. Indlela elula nenembileko ye-HPLC-UV spectrophotometric yasungulwa ukuthola i-melamine kufomula yomntwana kanye nobisi lwepuyere. Indlela le yaqinisekiswa ukuqinisekisa ukuthembeka nokunemba kwayo. Imikhawulo yokuthola nokulinganisa yendlela itjengiswe bona iyazwela ngokwaneleko ukulinganisa amazinga we-melamine kufomula yomntwana kanye nobisi lwepuyere. Ngokuya ngedatha yethu, i-melamine yatholakala emasampula amanengi we-Iran. Woke amazinga we-melamine atholakeleko bekangaphasi kwemikhawulo ephezulu evunyelweko ebekwe yi-CAC, okutjengisa bona ukusetjenziswa kwemihlobo le yemikhiqizo yobisi akubeki ingozi epilweni yabantu.
Zoke iinsetjenziswa zamakhemikhali ezisetjenzisiweko bezisezingeni lokuhlaziya: i-melamine (2,4,6-triamino-1,3,5-triazine) 99% emsulwa (Sigma-Aldrich, St. Louis, MO); I-HPLC-grade acetonitrile (Merck, Darmstadt, Germany); amanzi ahlwengileko khulu (i-Millipore, e-Morfheim, e-France). Iinhlungi zesirinji ezilahlwako (i-Chromafil Xtra PVDF-45/25, ubukhulu be-pore 0.45 μm, ububanzi be-membrane 25 mm) (Macherey-Nagel, Düren, Germany).
I-ultrasonic bath (Elma, Germany), i-centrifuge (Beckman Coulter, Krefeld, Germany) kanye ne-HPLC (KNAUER, Germany) kwasetjenziselwa ukulungiselela amasampula.
Kwasetjenziswa i-chromatograph ye-liquid esebenza kuhle khulu (i-KNAUER, e-Germany) ene-UV detector. Ubujamo bokuhlaziywa kwe-HPLC bebunje: kwasetjenziswa ihlelo le-UHPLC Ultimate elifakwe ikholomu yokuhlaziya ye-ODS-3 C18 (4.6 mm × 250 mm, ubukhulu beenhlayiya 5 μm) (MZ, i-Germany). I-HPLC eluent (isigaba esihambako) bekuyinhlanganisela ye-TFA/methanol (450:50 mL) enezinga lokugeleza le-1 mL min-1. Ubude begagasi lokuthola bekungu-242 nm. Ivolumu yomjovo beyiyi-100 μL, izinga lokutjhisa lekholomu belingu-20 °C. Njengombana isikhathi sokugcina umuthi side (imizuzu eli-15), umjovo olandelako kufanele wenziwe ngemva kwemizuzu ema-25. I-melamine yabonwa ngokumadanisa isikhathi sokugcinwa kanye ne-UV spectrum peak yamazinga we-melamine.
Isixazululo esijayelekileko se-melamine (10 μg/mL) salungiswa kusetjenziswa amanzi begodu sagcinwa esiqandisini (4 °C) kude nokukhanya. Hlikihla isisombululo sesitoko ngesigaba esihambako bese ulungiselela iinsombululo ezijayelekileko ezisebenzako. Isisombululo ngasinye esijayelekileko sajovwa ku-HPLC amahlandla ali-7. I-ikhweshini yokulinganisa 10 yabalwa ngokuhlaziywa kokubuyela emuva kwendawo ephezulu enqunywe kanye nokugxila okunqunyiwe.
Ipuyere yebisi lenkomo etholakala emabhizinisini (amasampula ama-20) kanye namasampula wamabhrendi ahlukileko webisi lenkomo elisekelwe ebantwaneni (amasampula ama-20) athengwe emasuphamakethe wendawo kanye namakhemisi e-Iran ukondla abantwana beminyaka ehlukileko (0–6 iinyanga, 6–12 iinyanga, kanye >>12 iinyanga) begodu agcinwe efrijini (4°C) bekube kulapho kuhlaziywa khona. Bese, i-1 ± 0.01 g ye-homogenized milk powder yalinganiswa begodu yahlanganiswa ne-acetonitrile:amanzi (50:50, v/v; 5 mL). Umxube lo wavuselelwa umzuzu owodwa, bese utjhugululwa nge-ultrasonic imizuzu ema-30, bese ekugcineni wanyakaziswa umzuzu owodwa. Umxube lo wabese utjhugululwa ku-9000 × g imizuzu eli-10 emazingeni womtjhiso wegumbi begodu okusezingeni eliphezulu kwahlungwa ngaphakathi kwe-2 ml ye-autosampler vial kusetjenziswa i-0.45 μm ye-syringe filter. I-filtrate (250 μl) yahlanganiswa namanzi (750 μl) bese yajovwa ku-HPLC system10,42.
Ukuqinisekisa indlela, siqunte ukubuyiselwa, ukunemba, umkhawulo wokuthola (LOD), umkhawulo wokulinganisa (LOQ), nokunemba ngaphasi kwemibandela emihle. I-LOD yachazwa njengokuqukethwe kwesampula okunezinga eliphezulu eliphindwe kathathu izinga lomsindo wesisekelo. Ngakelinye ihlangothi, okuqukethwe kwesampula okunezinga eliphezulu eliphindwe kali-10 isilinganiso sesiginali-kuya-nomsindo kwachazwa njenge-LOQ.
Ipendulo yedivayisi yanqunywa kusetjenziswa ijika lokulinganisa elinamaphuzu wedatha alikhomba. Kwasetjenziswa izinto ezihlukahlukeneko ze-melamine (0, 0.2, 0.3, 0.5, 0.8, 1 no-1.2). Ukulandelana kwenqubo yokubala i-melamine kwatholakala. Ukungezelela, amazinga ahlukileko we-melamine afakwa emasampula anganalitho. Ikhefu lokulinganisa lakhiwa ngokuragela phambili nokujova i-0.1–1.2 μg mL−1 yesisombululo se-melamine esijayelekileko kumasampula wobisi lwabantwana kanye nobisi oluyimpuphu begodu i-R2 yayo = 0.9925. Ukunemba kwahlolwa ngokuphindaphindeka nokukhiqizwa kwenqubo begodu kwafezwa ngokujova amasampula emalangeni wokuthoma namathathu alandelako (ngokuphindaphindwe kathathu). Ukuphindaphindeka kwendlela kwahlolwa ngokubala i-RSD % yamazinga amathathu ahlukileko we-melamine eyengeziweko. Iimfundo zokubuyisela zenziwa ukuthola ukunemba. Izinga lokubuyiswa ngendlela yokukhipha labalwa emazingeni amathathu wokugxila kwe-melamine (0.1, 1.2, 2) kumasampula wefomula yomntwana nebisi elomileko9,11,15.
Ukudla okulinganiselweko kwansuku zonke (i-EDI) kwatholakala kusetjenziswa ifomula elandelako: i-EDI = Ci × Cc/BW.
Lapho i-Ci isilinganiso se-melamine, i-Cc iyindlela yokusetjenziswa kwebisi begodu i-BW iyisilinganiso sesisindo sabantwana.
Ukuhlaziywa kwedatha kwenziwa kusetjenziswa i-SPSS 24. Ukujayelekileko kwahlolwa kusetjenziswa i-Kolmogorov-Smirnov test; yoke idatha bekuyizivivinyo ezingekho emthethweni (p = 0). Ngalokho-ke, i-Kruskal-Wallis test kanye ne-Mann-Whitney test kwasetjenziselwa ukuthola umehluko oqakathekileko hlangana namaqembu.
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