8. UV-vis spectra of (a) AgNO3, (b) COL, (c) mixture of AgNO3 and COL and (d) COL-AgNPs.
300 400 500 600
0.0
0.3
0.6
0.9
d
c
a
b
Absorbance
Wavelength (nm)
7
9. UV-vis spectra of (a) freshly prepared and (b) 5-months aged COL-AgNPs. Inset: (A) and (B), Photograph of
corresponding NPs.
a
b
8
12. HR-TEM images of COL-AgNPs with different magnifications. Inset: crystal lattices of COL-AgNPs.
The obtained COL-AgNPs are monodispersed and the range of particles diameter was calculated to be
16.37 ± 0.15 nm, by HR-TEM. 11
13. pH effect of the only COL-AgNP at various pH.
3 4 5 6 7 8 9 10 11 12
0.5
0.6
0.7
0.8
0.9
1.0
Absorbance
pH
12
14. Time effect of the COL-AgNPs at different Time Vs absorbance.
13
16. UV-vis spectra of COL-AgNPs in the presence of different concentration of I- (a) 0, (b) 0.498, (c) 0.998, (d) 1.48, (e)
1.9, (f) 2.44, (g) 2.91 and (h) 3.38×10-6 M I- in PBS at pH 7.2. Inset: Photographs of (i) before and (ii) after the
addition of 3.38×10-6 M I-. The detection limit (LOD) was found to be 108.5×10-9 (S/N=3). 15
17. DPV of the COL-AgNPs record before addition of iodide (a) and after addition of concentration (b), 0.5 and (c), 2
micro molar iodide in 0.05 NaCl supporting electrolyte at a scan rate 0.1Vs-1 scan from -0.2 to 1 V
16
18. TEM image of COL-AgNPs in the presence of 0.998 uM Iodide. 4.61 ± 0.12 nm
17
19. UV- vis spectrum of only of COL solution (a) and addition of I- solution various(b), 0.744 (c),1.48 (d),2.20
(e),2.91 (f),3.61 and (g), 4.31×10-5 M I- concertation.
200 400 600
0
1
2
a
b
c
d
e
f
g
Absorbance
Wavelenth (nm)
18
22. 1.22 × 10-2M of common interferences such as Br-, F-, Cl-, NO2-, NO3-, H2PO4-, SO4-, CN-, AcO-, CO3-, SCN- and
Interest 1.22 × 10-2M of above mention common potential interference did not interact for the
detection of 1.48 × 10-5M of iodide (825) fold higher. 21
25. UV-vis spectra of COL-AgNPs in the presence of different concentration of I- (a) 0, (b) 0.498, (c) 0.998, (d) 1.48, (e)
1.9, (f) 2.44, (g) 2.91 and (h) 3.38×10-6 M I- in PBS at pH 7.2. Inset: Photographs of (i) before and
(ii) after the addition of 3.38×10-6 M I-. 24
26. Fig. 3. UV-vis spectra of COL-AgNPs in the presence of different concentration of I- (a) 0, (b) 0.498, (c) 0.998, (d)
1.48, (e) 1.9, (f) 2.44, (g) 2.91 and (h) 3.38×10-6 M I- in PBS at pH 7.2. Inset: Photographs of (i) before
and (ii) after the addition of 3.38×10-6 M I-. 25
Editor's Notes
I am maruthu pandi, I am doing research nanomaterials based sensor under the superviser of dr. n. vasimalai.
Today I happy to discus my first research work
Iodide is essential micro minerals human body and it is supporting valuable function of growth of human body
Total body contains 20 mg of iodide, predominantly 80 % of iodide present thyroid gland (Adam apple)
WHO reported 86% people and 30% child affected iodide deficiency ( Indian country 92.7% people )
WHO is recommend level take 150 microgram / day and great special organization is iodine global network
Rich sources of iodide see foods, eggs, dairy products and iodized salt
So iodide level detection very important in biological science
I think, Now days few number of articles present iodide sensor
So I have interest iodide using Silver Nano
These days, silver nanoparticles are extensively used for the sensor applications. Because properties of silver nanoparticle following
Recent days, there are reports available for the detection of iodide, such as voltammetry 16, fluorescence 17, flame atomic absorption spectrometc., Whilst, these methods have some demerits, which includes long measuring etry 18, Gas Chromatography-Mass Spectrometry 19 and ion chromatography 20 time, lengthy procedure, high cost instrument etc., On the other hand, spectrophotometric and colorimetric detection method has gained momentum, due to their simple experimental setup, high sensitivity, less time consumption
The paper based kit also was prepared by using wax-printed paper and test for on-site monitoring of iodide.
Then I discuss synthesise nanoparticles
The COL-AgNPs was synthesized by wet chemical method. Briefly, a solution AgNO3 (2 mL 0.01M), Then, 25 mL of water was added in to a 50 mL beaker. Under mixture solution allowed vigorous stirring. After 5 min (3 mL 1%) of Chitosan oligosaccharide lactate transferred into 50 mL beaker and allowed to stirrer for 5 min. Then, 0.3 mL of 0.25% NaBH4 added to the above mixture with constant stirring, after 5 min later a brownish-yellow solution was obtained. The resulted COL-AgNPs were purified by centrifugation, Finally, purified COL-AgNPs was stored 4o C.
The synthesised col-Agnps centrifuge and dills lysis purification method
Then use characterisation teqnices likes that
First I was take uv-vis spectra 400 nm and colour of agnps was yellow brown , this result is primilary conformed silver nano formation.
Next I was optimized silver nanoparticles synthesis procedure
I was use uv-vis spectra absence of excess of silver and ligand
The synthesised silver Nano check stability every month
Our nano 5 month stable
The synthesised silver nano dyring take xrd patten
Our col-agnps xrd patten is perfect matches previous JCPDS file No. 04-0783
functional groups of COL and COL capped AgNPs were characterized by
FT-IR spectral technique, presenc col agnps spectrum various s funtional group like that
These results are confirmed that the presence of COL on the surface of AgNPs
The size, dispersity and morphology were examined by HR-TEM images. (Fig-3 A) shows the HR-TEM image with different magnification
This HR-TEM image was indicate that the synthesis COL-AgNPs are crystalline nature and highly pure
The effect of on COL-AgNPs in was monitor UV-vis spectrophotometer by using phosphate buffer solution (0.2M) the pH of COL-AgNPs solution was fixed pH 3 to pH 12
Neutral ph higly stable silver nano
The effect of on COL-AgNPs in the was monitor UV-vis spectrophotometer by using phosphate buffer solution (0.2M) the pH of COL-AgNPs solution was fixed pH 3 to pH 12
The effect of on COL-AgNPs in was monitor UV-vis spectrophotometer by using phosphate buffer solution (0.2M) the7.2 pH varies time interval
we have optimized 15 min reaction time as suitable time for the formation AgI
Then chractersatrized silver nano used futher going application
The interaction of iodide and COL-AgNPs was monitored by UV-vis spectrophotometer
of COL-AgNPs exhibits the SPR band at 400 nm (Fig-4; curve a) and the colour of solution is brownish-yellow.
After the various addition of iodide in Ph 7.2 condition and reaction time was 15min
Increasing of iodide and spr band is disappeared and formation of new peak agI 424 nm
Finally nano was colour disapped and formation Agi
Further we have studied the interaction of COL-AgNPs with iodide by Differential pulse voltammetry (DPV) technique. Shows the DPV of COL-AgNPs in the presence and absence of iodide.
It well now that the oxidation peak of AgNPs will be shifted to lower peak potential and their current intensity will be enhanced
Iodide is one the surface of iodide is preventing the oxidation of AgNPs, and next one
second addition 2 µM of iodide gives new oxidation peak 0.7935 V excess of amount iodide
This is result indicates nano size reduce like itchig effet and formation AgI
We have characterized the COL-AgNPs after the addition of 0.998 of iodide by HR-TEM.
This is result was indicate iodide itching of nanoparticles and formation Agi
And we have take ligand only and addition of iodide was not change any peak
This result was indicated ligand does not interact this senor manganisum
In the Presence of iodide sensing of UV-Vis , DPV and tem studeisi
Then we were cothoru privous repoted drew the shrmatic respresnetation of iodide
Silver react ligand formation of nanoparticle and added of known quantity of iodide to form Agi
It is very impertinent effect of co-existing ion for a new detection method iodide sensor
We have take above mention common potential interference did not interact silver nano
The COL-AgNPs was successfully applied for the detection of iodide in water sample (Tap water, River water, Pound water), urine sample, blood serum sample and food sample of Kelp. Water, blood serum and urine sample did not have iodide content
we spiked the known amount iodide in to the real sample, which was decreased the absorption of SPR band. A good recovery was observed from 97 % and 99.7 %, with an real sample spiked with iodide
We weare take microplate and add Known amount of Nano
And addition of various concentration of iodide , colour nano slowly disappeared
Further we have take microplate reader absorbance
This is result good linear r2 very good match Uv-Vis sperctrum
chromatography paper sheet solid ink printer and well diameter 1 cm
Cut it wax-printed paper was placed onto a hot plate at 150°C for 2 min
100 μL of COL-AgNPs were added and allowed to dry at room temperature for 30 min and addition iodide known concentration
Colour was disappeared all well cut and put microplate plate
Finally, the absorbance intensity of the paper (each well area) was measured using a Synergy HT microplate reader
The result are conformed that our paper based platform provides advantage including low cost, simple experimental step, test screening and good ability to performing real sample on site monitor of iodide in the biological and environmental samples.
