Anal. Method Environ. Chem. J. 3 (2) (2020) 21-33

Separation and determination of mercury from nail and hair

in petrochemical workers based on silver carbon nanotubes

by microwave-assisted headspace sorbent trap

Daniel Soleymania, Sahar Zargarib and Ali Faghihi-Zarandia,*

a Occupational Health Engineering Department, Modeling in Health Research Center, Institute

for Futures Studies in Health,Kerman University of Medical sciences, Kerman, Iran

bSoftware Engineer, Statistical sciences and engineering, Department of Web development and software engineering,

Research Institute of Petroleum Industry, Tehran, Iran

ABSTRACT

In this work, the occupational analytical chemistry was developed

for determination of chronic exposure of mercury in nail and hair in

petrochemical workers (Age: 30-50, Men). By experimental procedure,

100 mg of hair and nail of workers was prepared by washing / grinding

and then the powder was dried in oven for 20 min at 95oC. 20 mg of hair

or nail samples added to reagents (HNO3/H2O2; 5:1) in polyethylene

tube (PET) of microwave digestion and the mercury in resulting

solution was removed with silver nanoparticles pasted on multi-walled

carbon nanotubes (Ag-MWCNTs) which were placed in head space of

separator. After microwave digestion for 25 min, the mercury vapor was

removed by Ag-MWCNTs as the headspace sorbent trap (HSST) under

hood conditions. Finally, the mercury in sorbent was online determined

by cold vapor atomic absorption spectrometry (CV-AAS) after heat

process at 250oC in presence of Ar gas. The capacity adsorptions of Ag-

MWCNTs and MWCNTs for mercury removal from air were obtained

205.4 mg g-1 and 63.7 mg g-1, respectively. The mean of mercury in nail

and hair in workers and healthy peoples was achieved (15.2±3.7 μg g-1;

11.6± 2.6 μg g-1) and (0.16±0.05 μg g-1; 0.24± 0.03 μg g-1), respectively

(RSD<5%). The validation of method was done by certied reference

material (CRM).

Keywords:

Mercury,

Nail and Hair,

Silver multi-walled carbon

nanotubes,

Microwave-assisted headspace

removal

ARTICLE INFO:

Received 29 Feb 2020

Revised form 17 Apr 2020

Accepted 14 May 2020

Available online 27 Jun 2020

* Corresponding Author: Ali Faghihi-Zarandi

Email: alifaghihi60@yahoo.com

https://doi.org/10.24200/amecj.v3.i02.99

1. Introduction

Mercury, as a trace heavy metal element, is the

only common metal which is liquid at ordinary

temperatures and has a high vapor pressure [1].

Atmospheric mercury is present in three forms:

metallic or elemental mercury (Hg0), oxidized or

inorganic mercury (Hg2+) and particulate-bound

mercury with organic materials such as methyl (R-

Hg) [2]. Each of these forms has different impacts

on health surveillance and requires different

countermeasures to avoid exposure. Hg0 is oxidized

to inorganic forms of Hg2+, when entering the

atmosphere. Elemental mercury in its gaseous form

is the main form of mercury in the atmosphere with

atmospheric lifetime of approximately 6–24 months

[3]. It is a pollutant of great concern due to its volatility,

toxicity, persistence, and bioaccumulation in the

environment and its neurotoxic impact on human

health [4,5]. Mercury vapors are well absorbed into

blood through the lungs (approximately 80%) and can

easily cross the blood-brain barrier as a lipid-soluble

substance in human body tissues such as brain and

Research Article, Issue 2

Analytical Methods in Environmental Chemistry Journal

Journal home page: www.amecj.com/ir

AMECJ

------------------------

renal [6]. Chlor-alkali factories using mercury metal

as a liquid electrode in the manufacturing of chlorine

(Cl2) and sodium hydroxide (NaOH) by electrolysis

release of the mercury vapor in air and so, it causes

to disease in workers by exposure of the workers to

mercury [7]. Chlor–alkali plants (CAP) which use

mercury (Hg) in electrolytic cell manufacture has

been identied as one of the main sources of Hg

pollution in environmental air. Although alternative

methods were established to replace the Hg-cell

process, many older plants are still in operation in

some undeveloped areas. In addition, many amounts

of mercury enter to environment by different

sources such as chemical factories, petrochemical

activity, volcanoes, forest res, and fossil fuels [8].

Bioaccumulation of mercury in the human body

changes the normal cell/tissues/organs and cause to

cancer. It can damage the physiological activities of

the human body especially in the brain and renal,

even at very low concentrations of mercury [9]. The

primary target for Hg exposure is the central nervous

system (CNS) and then, it can also damage many organ

systems such as liver and renal through its ephemeral

and residual systemic distribution [10] Finally, the

chronic mercury exposure can be damaged the cells

of kidney [11] and central nervous system (CNS)

[12]. In addition, the other organs/systems such as

the immune system, reproduction and cardiovascular

system can also be affected by mercury exposure

[13]. The mercury exposure has adverse health effect

in human body and can depend on the form of the

mercury, time and dose of exposure [14]. Acute, high-

dose exposure to elemental mercury vapor may cause

to pneumonitis. At low levels, the acute lung injury,

insomnia, headaches, disturbances in sensations and

changes in nerve responses is obtained and then, the

chronic inhalation cause to many problems include,

tremor, gingivitis, particularly irritability, depression,

short-term memory loss, fatigue, anorexia, and

sleep disturbance [15]. In the general population,

the total blood mercury concentration is due mostly

to the dietary intake of organic forms, particularly

methyl mercury and urinary mercury consists mostly

of inorganic mercury forms [15]. Several studies

identied a signicant positive association between

mercury in hair samples and hypertension (blood

pressure); whereby the exposure dose is an important

factor for determining the toxic effects of mercury

[16]. Hair mercury concentration as a biomarker

of organic and inorganic mercury exposure can be

provided the information over a denable period

of time, based upon sequential analyses of hair

segments, to represent both the magnitude and timing

of past exposure. However, the mercury analysis in

hair have two problems. The rst concerns the origin

of the measured elements, and the second concerns

the biological signicance that may be given to the

level of the elements. Unlike hair, total blood mercury

levels also include inorganic mercury, which may

be of importance in certain contexts. It is generally

considered the appropriate indicator of the absorbed

dose. Urinary mercury concentrations are widely used

as a biomarker of mercury exposure from elemental or

inorganic mercury [17]. Note, the inorganic mercury

can be changed to organic forms by high concentration

of mercury or chronic exposure of mercury. It is

very important to develop a novel analytical method

for determination of heavy metals in environment

and biological samples for monitoring the severity

of heavy metal pollution. At the present time, the

most well-known methods for detecting heavy

metals are atomic absorbance spectrometry (AAS)

[18], atomic uorescence spectrometry (AFS) [19],

electrochemical analysis, inductively coupled plasma

(ICP) [20], high performance liquid chromatography

(HPLC) [21] and capillary electrophoresis [22].

However, these methods generally need a sample

preparation or extraction procedure [23]. Recently,

the cold vapor atomic absorption spectrometry (CV-

AAS) was used as a favorite analytical technique for

mercury analyses in various types of samples [24], but

it has been necessary to develop with preconcentration

methods that allow mercury determination at ultra-

trace levels [25]. Liquid-liquid extraction/micro

extraction (LLE/LLME) and solid-phase extraction/

micro solid-phase extraction (SPE&MSPE) are the

most commonly employed methods to achieve the

separation and preconcentration of metal ions [26-28].

In this study, the chronic exposure of mercury in nail

and hair of petrochemical workers was determined

Anal. Method Environ. Chem. J. 3 (2) (2020) 21-33

by microwave-assisted headspace removal procedure

(MAHR). By procedure, the microwave based on

silver nanoparticles passed on multi-walled carbon

nanotubes (Ag-MWCNTs) was used as head space

removal and mercury concentration was determined

by CV-AAS.

2. Experimental

2.1. Instrumental

Mercury was measured by an atomic absorption

spectrometer (AAS, GBC 932, Australia) equipped

with a ow injection cold vapor accessory (FI-CV).

The background correction with a deuterium-lamp

and hollow-cathode lamp of mercury was used. The

circulating cooling unit (CCU) caused to generation

of vapour of mercury in cold conditions. NaBH4 /

NaOH or SnCl2/HCl was used as reduction agents

for generating of mercury hydride which was moved

to liquid –gas separator by Ar. The conditions of

FI-CVAAS were shown in Table 1. The pH ranges

in liquid phase were adjusted and determined by a

Metrohm pH meter (744, Switzerland). The multi-

wave microwave system (MMS, Anton Paar 3000,

Austria) was used for digestion of hair and nail

samples which was converted the organic mercury

to inorganic mercury. Anton Paar’s 8-position rotor

(8SXQ80) and respective reaction vessels individually

equipped with variable temperature and ultraviolet

(UV) radiations. The temperature and pressure of

MMS were 220°C and 35 bar, respectively.

2.2. Reagents

All reagents with high purity as an analytical

grade were purchased from Merck (Darmstadt,

Germany). All samples were prepared with the

deionized water (DW) from Millipore water system

(USA). The standard stock solution of inorganic

mercury (1000 mg L-1 Hg(II) in 1% nitric acid) was

purchased from Fluka, Switzerland. The working

standard solutions were prepared daily by diluting

of standard solutions with DW. The solutions

were freshly prepared and stored just in a fridge

(4 °C) to prevent decomposition. First, 0.6% (w/v)

NaBH4 solution was prepared daily by dissolving

in 0.5% (w/v) sodium hydroxide (NaOH) and used

as a reducing agent. The glassware and plastics of

laboratory were cleaned by nitric acid (15%, v/v)

for at least 12 h and then washed with DW. Silver

nitrate, ammonia, formalin, and ethanol were

purchased from Merck Company (Germany).

2.3. Synthesis of AgNPs-MWCNTs

The silver nanoparticles passed on MWCNTs have

prepared. First, the mixture of MWCNTs (10 mg)

in 100 mL of DW solution was prepared and then,

0.3 g of T-X100 as a surfactant was dispersed in

mixture at 300 rpm stirring speed. The 0.5 g of

silver nitrate was added to the mixture (MWCNTs/

AgNO3/TX-100/DW) without heat in same stirring

speed (300 rpm). Finally, 2 mL of the ammonia

solution was added to above solution and diluted

with DW up to 0.5 L by stirring at 15 minute. Then,

12 mL of formalin as a reducing agent was added

to product in 5 min and by increasing the speed of

stirring (600-800 rpm), the AgNPs (20-100 nm)

were coated on the MWCNTs. For cleaning of the

MWCNTs from CH2O and NH3, the product was

washed with DW for 10 times. For preventing of

silver oxidation, the product (AgNPs-MWCNTs)

washed with Ethanol or increasing temperature up

to 180oC.

2.4. Procedure

As Figure 1, 20 mg of hair or nail samples and

reagents (HNO3 / H2O2; 5:1) was put into PET of

microwave digestion at UV/@220oC for 30 min.

Table 1. The conditions of mercury determination by

FI-CVAAS with closed cell

Features Value

Linear range 0.5-65 μg L-1

Working range 0.5-150 μg L-1

Wavelength 253.7 nm

Lamp current 4.0 mA

Slit 0.5 nm

Mode Peak Area surface

HCl carrier solution 37% 3.4 mol L-1

NaBH4 reducing agent, % (m/v) 0.6 (0.5% NaOH)

Argon ow rate 15.0 mL min-1

Sample ow rate 4.0 mL min-1

Reagent ow rate mL min-1

Silver carbon nanotubes for measuring mercury Daniel Soleymani et al

After digestion, the resulting solution was diluted

with DW up to 10 mL mixed with reducing reagents

(NaBH4/NaOH) in mixer. Then, the hydride form of

mercury in liquid phase was generated by reaction

loop before moved to separator by owrate of 100 ml

min-1. As ultra-trace mercury (sub ppb), the mercury

was preconcentrated by Ag-MWCNTs trap in head

space of separator. Finally, the concentration mercury

was online determined by closed cell FI-CV-AAS

after thermal desorption by heat accessory at 185oC

in presence of Ar gas. The peak area of absorption

was calculated as concentration of mercury in nail

or hair samples by Avanta software of FI-CV-AAS.

The conditions of procedure were shown in Table 2.

Fig.1. Determination mercury in nail and hair based on Ag-MWCNTs by HSST method

Table 2. The conditions of the headspace sorbent trap (HSST) method in nail, hair and water samples

by Ag-MWCNTs sorbent

Parameter Nail/Hair sample Water sample

PFa 32.2 35.1

LODb (n=10, ng L-1) 5.3 4.5

RSDc (%) 2.4 1.9

Linear range (μg L−1) 0.015– 2.1 0.013-1.85

Working range(μg L−1) 0.015– 4.7 0.013-4.4

Correlation coefcient 0.9991 0.9995

a Preconcentration factor, b Limit of detection,

c Relative standard deviation.

Anal. Method Environ. Chem. J. 3 (2) (2020) 21-33

The Ethical Committee of Kerman University of Medical Science (E.C.:IR.KMU.REC.1400.143) was

approved the project of human nail and hair samples which was considered based on guiding physicians in

human body research in human tissue by the world medical association declaration of Helsinki.

3. Results and Discussion

As chronic exposure of mercury in nail and hair

in petrochemical workers, the novel method based

on Ag-MWCNTs sorbent was used for mercury

determination by microwave-headspace sorbent

trap (MW-HSST) procedure. For optimization

recovery, the parameters such as, temperature,

owrate, adsorption capacity was studied. On the

other hand, validation of proposed method was

achieved based on spiking samples and Microwave

digestion coupled to gold MC-3000 as ultra-trace

analyzer of mercury (ppt). Based on results,

the recovery of Ag-MWCNTs and MWCNTs

sorbents was obtained 38.5 and 98.3, respectively.

The recoveries in Ag-MWCNTs and MWCNTs

sorbents were determined by MW-HSST procedure

(equation I). Furthermore, the adsorption capacity

of sorbents was considered by equation of II.

(Eq. I)

(Eq. II)

As equation I, a is the primary concentration of

mercury and b is the nal concentration of mercury,

the adsorption capacity (mg g-1) was shown in

equation of II and and (mg L-1) are before and

after adsorption of mercury concentration by Ag-

MWCNTs, V is the air volume as owrate and (g)

is the mass of Ag-MWCNTs.

3.1. Characterization

The specic surface area (SBET) of Ag-MWCNT

and MWCNTs were obtained from the BET

equation at 20oC. Decreasing of BET surface area of

Ag-MWCNT in comparison with initial MWCNT

was due to the grafting of silver nanoparticles on

walls of MWCNTs.

The SEM micrographs of MWCNTs and Ag-

MWCNTs were shown in Figure 2a and 2b. The

diameter of MWCNTs and Ag-MWCNTs is

approximately between 30-100 nm. The XRD

patterns of MWNTs and Ag-MWCNTs were shown

in Figure 3. The TEM micrographs (Germany,

Philips CM30, 250 kV) showed the morphology

of the MWCNTs and Ag-MWCNTs particles.

Nano particles of MWNTs and Ag-MWCNTs were

dissolved in ethanol by shaking for 15 min and a

drop of the ethanol was used by TEM instrument.

The similar TEM micrographs for MWNTs and

Ag-MWCNTs were obtained about 40 nm (Fig. 4a

and 4b).

Fig. 2a. The SEM of MWCNTs.

Fig. 2b. The SEM of Ag-MWCNTs.

Silver carbon nanotubes for measuring mercury Daniel Soleymani et al

Fig. 3. The XRD of MWCNTs and Ag-MWCNTs

Fig. 4a. The TEM of MWCNTs. Fig. 4b. The TEM of Ag-MWCNTs

Anal. Method Environ. Chem. J. 3 (2) (2020) 21-33

3.2. Effect of temperature

The effect of temperature for absorption and

desorption mercury by Ag-MWCNTs sorbent was

investigated. The temperatures between 20-2000C

was studied for procedure. As results, the recovery

of Ag-MWCNTs and MWCNTs was decreased in

high temperature and the mercury can be desorbed

from Ag-MWCNTs and MWCNTs at 185oC and

more than 80oC. The results showed, the optimum

temperature for adsorption and desorption mercury

from Ag-MWCNTs sorbent was obtained 25-35oC

and 185oC (Fig. 5).

At temperature more than 35oC, the removal

efciency of mercury by Ag-MWCNTs were

decreased. Temperature had more effected on

mercury removal by Ag-MWCNTs as compared to

humidity.

3.3. Effect of ow rate

The main factor for adsorption of mercury on Ag-

MWCNTs sorbent was depended on owrate of Argon

gas which was caused to increase interaction Hg with

Ag as amalgamation form (Ag-Hg). As optimized

conditions for removal of mercury by headspace

sorbent trap (HSST) method, the ow rates must be

evaluated. So, the ow rates between 50 - 500 mL min-

1 were optimized for Ag-MWCNTs and MWCNTs at

room temperature. The ow rate was determined by

a rotameter accessory in room temperature. In high

and low owrate, the rate of adsorption was reduced

and increased, respectively. The results showed

that maximum recovery for mercury removal was

achieved by Ag-MWCNTs at owrate 100 ml min-1.

Figure 6 showed the effects of ow rate on the removal

efciency of mercury by HSST method.

Fig. 5. The effect of temperature on desorption mercury from

Ag-MWCNTs and MWCNTs sorbents by HSST method.

Fig. 6. The effect of ow rate on removal of mercury vapor from liquid

phase by Ag-MWCNTs and MWCNTs sorbents

Silver carbon nanotubes for measuring mercury Daniel Soleymani et al

3.4. Adsorption capacity

In this study, the adsorption capacity of mercury

by Ag-MWCNTs, and MWCNTs in batch system

has obtained 205.4 mg g-1, 63.7 mg g-1, respectively

which was shown in Figure 7. The closed special

vial (10 mL) was used with 5 mL of liquid standard

mercury value (100 mg), 0.2 g of Ag-MWCNTs,

and MWCNTs sorbents in head space of vial and

reducing agents which was added by syringe with

beside input port. After 5, 10, 15, 20 min, the mercury

in sorbent determined by CV-AAS. The results

showed us, the maximum removal was achieved by

Ag-MWCNTs after 15 min. By procedure, the nal

concentration in sorbent was obtained 41.1 mg of

mercury after thermal desorption.

3.5. Validation

The accurate and precise results for mercury

determination in nail /hair are important factor for

human samples. So, the mercury results based on

Ag-MWCNTs must be validated by MW-HSST

procedure. First, the different concentration of

standard mercury solutions from 0.5 to 5 μg L-1 was

prepared. For validation, the different concentrations

of mercury were used for spiking of nail, hair and

water samples by Ag-MWCNTs sorbents (Table

3). The removal efciency of sorbents based on

MW-HSST was evaluated. For method validation

ICP analyzer was used for nail and hair samples

after sample digestion (Table 4). In addition, the

removal efciency of mercury in water and gas

phase by different sorbents was compared to MW-

HSST procedure (Table 5). According to table5,

the Ag-MWCNTs have more efficiency than other

sorbents. The Ethical Code for human nail and

hair samples approved by Kerman University of

Medical Science (E.C.: IR.KMU.REC. 1400.143).

Fig. 7. The absorption capacity of mercury by Ag-MWCNTs and MWCNTs sorbents by HSST method

Table 3. Validation of MW-HSST procedure for total mercury determination in nail, hair and water samples by

spiking of real samples

Sample Added (μg L−1)Found (μg L−1) Recovery(%)

Human Nail ------ 1.43 ± 0.05 ------

1.5 2.91 ± 0.12 98.6

Human Nail ------ 0.17 ± 0.01 ------

0.2 0.36 ± 0.02 95.0

Human Hair ------ 1.98 ± 0.08 ------

2.0 4.02 ± 0.17 102

Human Hair ------ 0.55 ± 0.02 ------

0.5 1.03 ± 0.04 95.8

Well Water ------ 0.38 ± 0.01 ------

0.5 0.86 ± 0.03 96.0

Anal. Method Environ. Chem. J. 3 (2) (2020) 21-33

3.6. Discussion

Krawczyk et al was used TiO2 nanoparticles (NPs)

as adsorbent for preconcentration and determination

of mercury species (Hg total, Hg2+ and CH3Hg+) in

biological, environmental and water samples. The

mercury extracted based on ultrasound-assisted

dispersive micro solid-phase extraction (USA

DMSPE) and determined by cold vapor atomic

absorption spectrometry (CV AAS). The detection

limit of the method for Hg2+ and relative standard

deviations (RSD%) was obtained 4 ng L−1 and

4–20%, respectively. The mercury was separated

from liquid phase with 10 mg of TiO2 at pH 7.5[39].

In addition, Ma et al showed that the mercaptopropyl

Table 4. ICP analyzer was used for validation of proposed method for mercury

determination in nail and hair samples after sample digestion

Sample ICP-MS (μg L−1)Added (μg L−1)Found (μg L−1) Recovery (%)

Nail 1.24 ± 0.03 ------ 1.20 ± 0.05 96.8

------ 1.0 2.17 ± 0.09 97.0

Hair 0.52 ------ 0.54 ± 0.03 103.8

------ 0.5 1.02 ± 0.04 96.0

Table 5. Comparing of Ag-MWCNTs based on MW-HSST procedure with different sorbents

by published method

ReferenceRecovery

Absorption Capacity

( mg g−1)

TechniqueMatrixSorbents

[29]----0.70–3.83 AdsorptionReal waters

Solid-phase extraction

with multiwalled carbon

nanotubes

[30]----9.3 AmalgamationFlue gasesAg-CNT

[31]98%91.8

Amalgamation/

SPGE

Air/Articial air

Silver nano particles/

MGBs

[32]35.3%----

Microwave

assisted catalytic

Flue gas

Mn/zeolite catalyst

[33]98.5%--------

Gas Porous carbon-supported

CuCl2

[34]----497.84 (μg·g–1)Adsorption

Coal Combustion

Fuel Gas

Nano-ZnS

[35]75.58%----Chemisorption Flue gasnano-ceramic

[36]97%145 (μmol g-1) Adsorption Natural Waters Au NP–Al2O3

[37]96%376.3 ----Aqueous solutions

Silver/quartz

nanocomposite

[38]75%----ComplexationWater

magnetic nanoparticles

coated with yam peel

biomass (MNP-YP)

[40]96.477.0

SPE/Anodic

Stripping

Voltammetry

WaterReduced graphene oxide

This work98.8205.4MW-HSSTNail/HairAg-MWCNTs

Silver carbon nanotubes for measuring mercury Daniel Soleymani et al

trimethoxysilane (MPTS) modied on Fe3O4@SiO2

as a magnetic nanoparticles (MNPs) can used for

the speciation of mercury in environmental water

and human hair samples. The characterization of

(MPTS-MNPs) was obtained by Fourier transform

infrared spectrometer (FT-IR), transmission

electron microscope (TEM) and vibrating sample

magnetometer (VSM). In the optimized conditions,

the limits of detection (LOD) for CH3Hg+ and total

Hg were achieved 1.6 and 1.9 ng L-1, respectively.

This method successfully applied for the speciation

of CH3Hg+ and Hg2+ in water and hair samples [40].

A novel Fe3O4@SiO2@polythiophene magnetic

nanocomposite was synthesized by Abolhasani

et al. They could determine the Hg(II) ions in sea

food samples. After sample digestion, the mercury

was determined by cold vapor atomic absorption

spectrometry (CV AAS). Under the optimum

condition, the LOD (20 ng L−1) and RSD% (9.2 %)

were obtained. The capacity adsorption of Fe3O4@

SiO2@polythiophene magnetic nanocomposite

was 59 mg g−1 which was lower than our proposed

method base on Ag-MWCNTs (184.3 mg g-1)

[41]. In other study, Akbar et al was reported a

SPE method based on mGO@SiO2@2-MPATD

nanocomposite for determination of mercury in the

water and seafood samples. The characterization

was obtained by FT-IR, SEM, and elemental

analysis techniques. After adsorption and elution

steps, the concentration of Hg (II) was measured

by CV-AAS. Under the optimized conditions,

the limit of detection was 8 ng L−1. The capacity

adsorption of mGO@SiO2@2-MPATD was

obtained 236 mg g−1 which was higher than

proposed method by Ag-MWCNTs [42]. Also,

Krawczyk et al introduced the silver nanoparticles

(AgNPs) as solid sorbent for preconcentration and

determination of Hg2+ ions in water samples. The

limit of detection and RSD% was achieved 5 ng L-1

and 6-11%, respectively [43].

4. Conclusions

In this study, a robust analytical method based

on microwave coupled to headspace sorbent trap

(HSST) was developed for determination mercury

in nail and hair in petrochemical male workers

aged 30 to 60 years. Results showed the capacity

adsorptions of Ag-MWCNTs and MWCNTs for

mercury removal from the air were obtained 205.4

mg g-1 and 63.7 mg g-1, respectively. It means

that mercury removal from the air was increased

dramatically by silver nanoparticles pasted on

multi-walled carbon nanotubes. After nail/hair

digestion, the mercury in liquid phase converted

to hydride form (HgH2) and captured by silver

nanoparticles on MWCNTs as a sorbent trap in

head space of separator. The LOD and LOQ of

proposed procedure was obtained 5 ng L-1 and 15

ng L-1, respectively. Also, the mean of mercury

in nail and hair in workers and control group was

achieved (15.2 ±3.7 μg g-1; 11.6 ± 2.6 μg g-1) and

(0.16 ± 0.05 μg g-1; 0.24 ± 0.03 μg g-1), respectively

(RSD<5%). Regardless of the interfering factors,

the difference between these values is due to high

exposure with mercury.

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