24.4 Characterization of Biosynthesized Nanoparticles

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Table 24.2

Procedure for preparation of metal salt solutions, extract and storage.

Procedure

Storage

Metal salt solution

Prepared by dissolving the

required metal Ag, Au, Cu,

ZnO, Ag in 0.1, 0.5, 1 mM of

their metal salts in distilled

water

Prepared solution to be

retained in dark condition to

avoid photodegradation.

Cocoa pod shell

1 g in 100 ml distilled water,

boiled and filtered using

Whatman paper

Filtrate to be stored at 4 ^∘C.

Leaves

Required quantity of leaves

are boiled in distilled water.

Extract cooled and filtered

using Whatman paper.

Stored at 4 ^∘C prior to the

synthesis of the desired

nanoparticle.

Flower

1 g of dried flowers are added

to 100 ml of deionized water

and boiled in water bath for

10 min.

The extract is cooled to room

temperature prior to synthesis

of nanoparticles [13].

Fruit peel

10 g of processed peel is

transferred to 250 ml of

double distilled water.

Further heated at 60 ^∘C for

30 min

Extract cooled to room

temperature, filtered and

stored at 4 ^∘C [12].

washed several times to remove the excess extract and unreduced ions present in

the respective salt solution. Further, the pellets are used for characterization of the

biosynthesized nanoparticle.

24.4

Characterization of Biosynthesized Nanoparticles

Characterization protocol is an important tool in determining the size, shape, com-

position, and functional groups capped on the biosynthesized nanoparticles. The fol-

lowing are the specific instrumental approach used in the study of characterization:

24.4.1

UV Spectrophotometer

Colloidal solutions of biosynthesized nanoparticles exhibit SPR under ultraviolet–

visible spectrum. SPR is the total oscillation prevailed by surface electrons for

the range of incident wavelengths of light. When the size of a nanoparticle is

smaller than the wavelength of incident radiation, SPR is generated. At a specific

wavelength, maximum oscillation is recorded where SPR peak corresponds to the

unique characteristic feature of the synthesized nanoparticles at corresponding

wavelength of light. SPR can be determined by using a UV spectrophotometer.

Nanoparticles such as silver and gold exhibit characteristic SPR peak in the visible

region (400–700 nm).