仪器分析实验 (11).pdf

Food Chemistry Advances 1(2022)100017 Contents lists available at ScienceDirect Food Chemistry Advances journal homepage: Functionalization of biogenic silver nanoparticles with Vitamin B 12 for the detection of iron in food samples Sayali S.Harke a,Reshma V.Patil a,Mudasir A.Dar b,Sneha R.Pandit b,Kiran D.Pawar a,a School of Nanoscience and Biotechnology,Shivaji University,Kolhapur,Maharashtra,India b Department of Zoology,Savitribai Phule Pune University,Pune,Maharashtra 411007,India a r t i c l e i n f o Keywords:FAgNPs Fe+3 ions detection RSD UV-Vis spectrophotometry Atomic absorption spectroscopy a b s t r a c t A comprehensible,validated,and simple method was developed for the determination of Fe+3 ions in food sam-ples.To accomplish this,Vitamin B 12-functionalized biological silver nanoparticles(FAgNPs)were synthesised and employed.The test of sensitivity showed 2 mgL 1 as the limit of detection for Fe+3 ions by FAgNPs.The intra-day and inter-day recoveries of Fe+3 were observed in the range of 7888%and 7494%,respectively.Moreover,the procedure was successfully applied for Fe+3 ion detection in some cereals and commercially available baby food products.The application of FAgNPs-based methods showed high specificity and sensitivity,providing a promising strategy to detect low Fe+3 ion concentration in the range of 210 mgL 1.When compared to atomic absorption spectrophotometry,the detection efficiency of FAgNPs-based method was comparable and acceptable.The proposed methodology is a low-cost and portable nanoparticle-based technology for rapid assessment of Fe+3 ions with promising potential for practical implementation,beside being sustainable due to its biogenic nature.1.Introduction As an essential element for life,iron(Fe+3)plays a very important role in biochemical and metabolic pathways by acting as cofactor in many enzymatic reactions that take place in the mitochondria(Cai et al.,2011).As one of the most important and essential trace elements for both,plants and animals including humans,the insufficient intake of Fe+3 ions can lead to its deficiency causing anemia(Brugnara,2003).On the other hand,the high levels of Fe+3 ions are associated with an increased risk of cancer,heart disease,and other illnesses such as en-docrine problems,arthritis,diabetes,and liver disease(Niederau et al.,1996).Recently,Pawlak et al.(2018)studied the consumption of iron and its impacts on the overall health conditions of vegetarian and non-vegetarian people.The food-based approaches that help increase iron intake depend on reliable and relevant data about the iron composi-tion(content,as well as availability)of a food.Generally,there are two types of iron ions present in the food items that are distinguished as heme(from stable porphyrin complexes)and non-heme ions(from weak complexes or free iron).These forms differ markedly in their molecu-lar mechanisms such as absorption as well as bioavailability.Thus,from a nutritional point of view,both the total amount of iron and its chem-ical nature in foods are pivotal for proper metabolism(Schnfeldt&Hall,2011).Therefore,the development of sensitive and selective ana-Corresponding author.E-mail address:kdp.snstunishivaji.ac.in(K.D.Pawar).lytical methods for the detection of Fe+3 ions has received a great deal of interest in recent years.Currently,the presence of Fe+3 ions is analysed by using different techniques such as atomic absorption spectrometry(AAS),voltamme-try,colorimetry,spectrophotometry(Chereddy et al.,2012)and induc-tively coupled plasma-optical emission spectrometry(ICP-OES).Among these methods,ICP-OES provides a robust,rapid,and higher detec-tion limit.The atomic absorption spectrometry is another method that is commonly used to measure the concentration of elements at parts per million(ppm or mgL 1)levels,making it a sensitive technique.Al-though AAS is used extensively in industries and commercial laborato-ries,it is costly,difficult to handle,and requires trained analysts.Due to these limitations,researchers have utilized fluorescence quenching mechanism-based techniques for the detection of Fe+3 ions by fiber op-tic and fluorescence-based sensors.However,it is believed that sensors with a fluorescence enhancement signal are more effective while inter-acting with the analyte(Jung et al.,2010).These probes are not only hydrophobic and incompatible with aqueous environments,but also de-liver low detection limits with complicated instrumentation.Therefore,it becomes imperative to design simple,highly sensitive,and selective sensors for Fe+3 detection and establish an easy method for the deter-mination of trace Fe+3 ions.Due to their unique properties and simple synthesis methods,nanoparticles(NPs)are being explored for the pos-https:/doi.org/10.1016/j.focha.2022.100017 Received 30 October 2021;Received in revised form 30 December 2021;Accepted 24 January 2022 2772-753X/2022 The Author(s).Published by Elsevier Ltd.This is an open access article under the CC BY-NC-ND license(http:/creativecommons.org/licenses/by-nc-nd/4.0/)S.S.Harke,R.V.Patil,M.A.Dar et al.Food Chemistry Advances 1(2022)100017 sible applications in the development of analytical methods and sen-sors for selective and sensitive detection of metal ions,including Fe+3(Ganesharajah,2018).A variety of NPs possess several distinctive physical and chemical at-tributes that make them promising synthetic scaffolds for the creation of novel chemical and biological detection systems(Rosi&Mirkin,2005).Indeed,in the last few years,nanostructured materials such as noble metal NPs,quantum dots,and magnetic NPs have been employed in a broad spectrum of highly innovative approaches for assays of metal ions(Alivisatos,2004).Likewise,water-soluble carbon nanoparticles(CNPs)were also described for selective and sensitive detection of iron(III)ions in water,which is a simple,green,and cost-effective fluorescence-based analytical procedure(Singh&Mishra,2016).Notably,the colorimetric detection techniques are being employed to detect the metal ions in an aqueous solution because they are quick and cheap(Lee et al.,2014).At present,the development of metal NPs-based colorimetric methods for the detection of metal ions has attracted a great deal of attention due to their desirable features such as high surface plasmon resonance(SPR),stable dispersion,biocompatibility,and tuneable physical and chemi-cal properties(Dong et al.,2014).Among the NPs,gold nanoparticles(AuNPs)and silver nanoparticles(AgNPs)have fascinated researchers in the field of sensors.Due to SPR bands and tuneable optical proper-ties,silver nanoparticles have a strong absorption band in the visible region.Similarly,functionalized AuNPs have also been proven suitable to serve as sensitive and selective colorimetric probes for the detection of Fe+3 ions(Wu et al.,2011).Silver NPs have a growing popularity in sensing applications because of their physical,chemical,and biolog-ical properties that allow their use in the detection of various metal ions(Fe+3,Hg+2,Mn+2,Cu+2,Pb+2,Mg+2 ions)in various aqueous so-lutions from industrial or environmental wastes(Ganesharajah,2018).Additionally,AgNPs are more efficient and sensitive than AuNPs due to the higher molar extinction coefficient(Farhadi et al.,2012;Kar et al.,2016).Previously,a few groups of scientists detected Fe+3 content from maize flour,beans,and potatoes,etc.using AAS and ion chromatog-raphy techniques(Da-Col et al.,2009).However,to date,no attempt has been made to detect Fe+3 ions using NPs with a spectrophotometric approach.Vitamins are vital substances that are pivotal for the normal growth and development of animals.Among vitamins,the cyanocobalamin(Vi-tamin B 12)is essential for the development of red blood cells,cell metabolism,neuron functioning,and the production and processing of genetic materials like DNA within cells.However,the functionalization of nanoparticles by Vitamin B 12 is still elusive.In view of this objective,we attempted to functionalize silver nanoparticles with Vitamin B 12 for the efficient determination of Fe+3.To accomplish this,AgNPs were bi-ologically synthesised using plant extract,characterized,and then func-tionalized with Vitamin B 12 for increased surface functionality to enable their use in the development of a colorimetric probe for the detection of Fe+3 ions.After validating the assay by studying accuracy and pre-cision,its applicability was tested and extended for possible use in the detection of Fe+3 ions in food samples.The performance of the devel-oped assay was also compared with that of AAS-based detection of Fe+3 ions in the same food samples.The functionalized AgNPs probe might be considered as a cost-effective,and time-saving spectrophotometric assay for the detection of Fe+3 ions in food samples.2.Materials and methods 2.1.Chemicals,reagents and food products Silver nitrate(AgNO 3,A.R.99.9%)was purchased from SRL chemi-cals(Sisco Research Laboratories Pvt.Ltd.,India),whereas ferric chlo-ride anhydrous(FeCl 3,98%),sodium hydroxide(NaOH,98%),and Vita-min B 12(C 63 H 88 CoN 14 O 14 P,96%)were obtained from Hi-media(HiMe-dia Pvt.Ltd.,India).The hydrochloric acid(HCl,3538%)and Whatman filter paper grade 1 were procured from Thomas Baker(Thomas Baker Chemicals,Pvt.Ltd.India)and Cam Lab Limited(Cambridge,UK),re-spectively.Nine different food samples that included pulses:whole red lentil(WRL),black lentil(BL),petite yellow lentil(PYL),split chick-peas(SCP),split pigeon peas(SPP);legumes:groundnuts(GN);cress:garden cress seeds(GCS);commercially available baby food products(BFP)and Nachanisatva(NS)were purchased from the local markets.All aqueous solutions were prepared using sterile double distilled water(SDDW).2.2.Biogenic synthesis and characterization of AgNPs Plant-mediated biogenic AgNPs were synthesised using a previously reported method with slight modifications(Sadalage et al.,2020).Briefly,almond seeds were soaked in SDDW for 24 h,seed coats were manually segregated using surgical forceps,air-dried,and then crushed into a fine powder.Afterwards,46 g of seed coat powder were sus-pended in 100 mL of SDDW,boiled for 2 h,filtered through a Whatman filter paper grade 1,and then centrifuged at 10,000 rpm for 10 min.In a usual biogenic synthesis reaction,almond seed coat(ASC)extract was added to AgNO 3 solution(1 mM)in a 4:1 ratio.The pH was adjusted to 6 with 1 N NaOH and the reaction was incubated at 70 C for 15 min.The progress of the reaction and the synthesis of AgNPs were monitored visually by observing the change of color from colourless to brownish-yellow and recording the UV-Vis spectrum in the range of 250800 nm on a Bio-spectrophotometer(Eppendorf,Hamburg,Germany).To study the functional groups on the surface of AgNPs,Fourier transform in-frared(FTIR)spectra were recorded over the range of 4004000 cm 1 on an FTIR spectrometer(Shimadzu,Japan).The size and morphology of the synthesized AgNPs were imaged using a high-resolution transmis-sion electron microscope(HR-TEM),Jeol/JEM 2100(Jeol Ltd.,Tokyo,Japan).2.3.Functionalization of AgNPs with Vitamin B 12 and characterization To better employ AgNPs and increase the sensitivity of Fe+3 ion detection,AgNPs were functionalized with Vitamin B 12.One milliliter functionalization reaction was set up by mixing the Vitamin B 12(80 g/mL)from an aqueous stock solution of 1000 g/mL with col-loidal AgNPs solution in a 1:1 ratio and stirring for 10 min at room tem-perature(RT).This reaction was monitored and confirmed by recording the UV-Vis spectra in the range of 300600 nm for the study of spectral shift.Furthermore,the effects of parameters such as Vitamin B 12 con-centration and pH were investigated by varying the concentrations and pH in the ranges of 4080 g/mL and 210,respectively.The Vitamin B 12 functionalized AgNPs(FAgNPs)were then characterized and con-firmed by recording and comparing the FTIR spectra over the range of 4004000 cm 1 and the EDS spectra.2.4.Detection of Fe+3 ions by Vitamin B 12 functionalized silver nanoparticles The Fe+3 ions were determined by FAgNPs probe-based methods us-ing UV-Vis spectrophotometry.To achieve this,the Fe+3 ions in the con-centration range of 110 mgL 1 were reacted with colloidal FAgNPs solutions in a 1:1 ratio at pH 7.The reaction mixture was incubated for 10 min,and then SPR shifts of 10 nm in the range of 300600 nm were monitored as a mark of Fe+3 ion detection.To determine the limit of detection(LOD)and limit of quantification(LOQ),the colloidal FAg-NPs solution was reacted with Fe+3 ions in the range of 110 mgL 1 and 26 mgL 1,respectively followed by monitoring the SPR shifts.Based on the initial few experiments,the concentration range of Fe+3 ions was ascertained to be 110 mgL 1.The LOD was expressed as the lowest concentration of an analyte in the sample that can be detected,but not necessarily quantified,under the stated conditions of the test,whereas the LOQ was the lowest concentration of an analyte in a sample that can 2 S.S.Harke,R.V.Patil,M.A.Dar et al.Food Chemistry Advances 1(2022)100017 Fig.1.Characterization of ASC mediated biogenic AgNPs synthesis by(a)UV-Vis Spectroscopy(b)FTIR(c)TEM imaging.be determined with acceptable precision and accuracy under the stated conditions of the test.2.5.Quantitative determination of Fe+3 ions in real food samples To extend the applicability of our FAgNPs based assays,its perfor-mance for the quantitative determination of Fe+3 ions in real food sam-ples were demonstrated and compared with AAS-based assays.Briefly,10 g of each of nine food samples such as GN,GCS,WRL,BL,PYL,SCP,SPP,BFP,and NS were weighed and finely powdered using mortar and pestle for ashing.Then the powder was heated at 400 C in a muffle fur-nace(Bio-Technics,India)for 2 h to prepare ash.This step was carried out in a well-ventilated room and the heating time was varied depend-ing on the amount of sample and the rate at which the sample burnt to the ash.The samples of each food product under study were heated until greyish or blackish ash was formed.The produced ash contents were fur-ther powdered by using a mortar and pestle,and cooled subsequently.About 0.5 g of ash was added to the 5 mL of SDDW and mixed properly.The solution was further sonicated using an ultra-probe sonicator(Lab-man Scientific Instruments,India)for 5 min.The prepared ash solution was then centrifuged at 15,000 rpm for 15 min and the supernatant was taken as a food sample solution for Fe+3 ions detection.To study the effect of Vitamin B 12 functionalization on the efficacy of detection,we set up the quantitative detection reactions with both bare AgNPs and FAgNPs.The solution of the tested food sample was added in separate reactions to the AgNPs and FAgNPs solutions in a 1:1 ratio,in-cubated for 10 min,and the presence of Fe+3 ions was confirmed by the spectral shifts within the range of 300 to 600 nm.The standard graph of concentration(mgL 1)of Fe+3 ions versus absorption ratio(A 4