The determination of Silver Nanoparticles in

Water sources

Norah AlmadaniChem 4101

12/04/2009

What are Ag Nanoparticles

Nanoparticles could be of the same dimension as some biological molecules like proteins and nuclic acids therefore, functulized nanoparticles might intrude into the fold of biomolecules structures.

It is possible that nanosilver could pose a threat to the balance of human health. The toxicity of silver exhibited in liver cells was also shown to be mediated by oxidative stress, and silver nanoparticles were found to induce toxicity in germline stem cells2.

Reduction in size to the nanoscale level results in an enormous increase of surface to volume ratio, therefore, more molecules of the chemical are present on the surface, thus enhancing the intrinsic toxicity

Bactirial Inhibition of Ag Naonoparticles

Different shapes of Silver nanoparticles have different affects on bacterial cells; Ag NP’s in the sub 50 nm exhibit increase efficiency in inhibiting wide range of bacteria.

Ag NP’s of 10nm interact with bacterial cell producing electronic effect enhancing the reactivity of the NP’s.

Depending on the geometry of Ag NP’s the toxicity ranges 1-100 microgram.

The Problem

silver is known to have an anti-microbial activity, and if presence

in high concentration in water sources silver may be highly toxic

to living systems

Hypothesis

Engineered silver nanoparticles having the size 20nm-200nm have the toxicity to

destroy living systems cells and can be found in water sources using analytical

techniques.

Method of Choice ICP-MS8

Sample is pumped in to the nebulizer mixes with argon where the sample aresole forms, large droplets are removed from the aerosol as it passes through the cool chamber where the fine aerosol are swept to the Chanel of the plasma due to the electric field and travel through high temperature Ar plasma; there aerosol droplets are dried and decomposed and finally ionized.

Analyte ions are then focused by a series of ion lenses into a quadrupole mass analyzer, which separates the ions based on their m/z ratio. The mass analyzer consists of four parallel stainless steel rods to which a combination of AC and DC voltages are applied. The combination of these voltages allows the analyzer to transmit only ions of a specific m/z ratio.

The detector used is an electron multiplier

**American Society of Mass Spectrometry

**www.cartage.org.lb/.../ Inductively/icp-sche.gi

Calibration standards microgram/L

0, 0.025, 0.05, 0.0, 0.25, 0.5, 1.0,2,5, 5.0, 10, 20, 50, 100, 500, 1000, 2500, 5000

R2 0-5000 microg/L

0.9992

R2 0-100 0.9969

R2 0-5 0.9984

Experimental Design

*Calibration standards

Recovery 88.8%

RDS 5,6%

Detection limit s/n=3

0.006 micg/L

*Then having 6 samples spiked with 100 micg/L Ag

Sample Preparation4

Solution containing 10ng/mL Ag, Triton X-144 (0.2%) v/v, dithizone (1X10-3

molL-1

Buffer solution of pH 4 (100 mM acetate buffer)

Kept in 45°C thermostatic bath for 15min

Centrifuging at 3500 rpm for 10 min.

Cool in ice bath

Formation of two layers

aqueous

Surfastant rich phase

Remove by syringe

To reduce viscosityAdd 1.0 molL-1

HNO3 in MeOH

Sampling Procedure

Key features of instrument:High sensitivity.Speed.Removal of Ar- bace interfering species such

as Ar2 using H2 reaction mode.The removal power of the Octapol Reaction

System of matrix interference.

Agilent 7500ce ICPMS

Instrument Selection8

ConclusionAg nanoparticles could pose a threat to the balance of

human health

Ag NP”s of different shape cause bacterial inhibition, where the toxicity depends on the geomery

Analytical problem Ag NP’s presence in water sources

Flouresence, FAAS and ICPM are possible methods of determing the concentration of Ag NP’s

Mettod of choice ICPMS

Ag NP’s are extracted from water by (CPE) solid extraction phase

Quantitative measurment of Ag concentration is determined using standards and calibration curves.

Reference 1. EUROPEAN COMMISSION HEALTH & CONSUMER

PROTECTION DIRECTORATE-GENERAL SCIENTIFIC COMMITTEE ON EMERGINGAND NEWLY IDENTIFIED HEALTH RISKS (SCENIHR) “The appropriateness of existing methodologies to assess thepotential risks associated with engineered and adventitious products of nanotechnologies” Adopted by the SCENIHR during the 10th plenary meeting of 10 March 2006

2. “Unique Cellular Interaction of Silver Nanoparticles: Size-Dependent Generation of Reactive Oxygen Species” C. Carlson, S. M. Hussain, A. M. Schrand, L. K. Braydich-Stolle, K. L. Hess, R. L. Jones, and J. J. Schlager† “J. Phys. Chem. B 2008, 112, 13608–13619” 

3.”Silver nanoparticles as a new generation of antimicrobials” Mahendra Rai, Alka Yadav, Aniket Gade

4.”Cloud Point Extraction as an Advantageous Preconcentration Approach for Analysis of Trace Silver Nanoparticles in Environmental Waters” Jing-fu Liu, Jing-bo Chao, Rui Liu, Zhi-qiang Tan, Yong-guang Yin, Yuan Wu, and Gui-bin Jiang

6. “Fluorescence properties of Ag nanoparticles in water”, methanolandhexane Om ParkashSiwach,P.Sen _

 7. “Off-line determination of trace silver in water samples and standard reference materials by cloud point extraction–atomic absorption spectrometry” Ersin Kilinca*, Viia Lepaneb, Anu Viitakb, and Bahattin Gumgum

 8. aiglent 7500ce https://cp.chem.agilent.com/en-US/Newsletters/accessagilent/2009/jun/pages/envirolab.aspx

9. Skoog, Holler and Crouch, “Principles of Instrumental Analysis”, 6th