Solid Phase Extraction to On-Line Preconcentrate Trace Cadmium Using Chemically Modified Nano-Carbon Black with 3-Mercaptopropyltrimethoxysilane

Zappielo, Caroline D.; Nanicuacua, Daniel M.; Santos, Walter N. L. dos; Silva, Daniel L. F. da; Dall'Antônia, Luiz H.; Oliveira, Fernanda M. de; Clausen, Débora N.; Tarley, César R. T.

doi:10.5935/0103-5053.20160052

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Articles • J. Braz. Chem. Soc. 27 (10) • Oct 2016 • https://doi.org/10.5935/0103-5053.20160052 copy

Solid Phase Extraction to On-Line Preconcentrate Trace Cadmium Using Chemically Modified Nano-Carbon Black with 3-Mercaptopropyltrimethoxysilane

Authorship SCIMAGO INSTITUTIONS RANKINGS

Carbon black (CB) grafted with 3-mercaptopropyltrimethoxysilane (3-MPTMS) was used as solid phase extractor for Cd²⁺ in a flow injection system coupled to flame atomic absorption spectrometry (FAAS). The influence of pH, buffer concentration, preconcentration flow rate and eluent concentration on preconcentration of Cd²⁺ were investigated by means of chemometric tools. The characterization of the adsorbent chemically modified was performed by Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, Raman spectroscopy and textural analysis. To perform the on-line preconcentration, 20.0 mL of a pH 7.0 Cd²⁺ solution at a flow rate of 4.0 mL min⁻¹ was loaded through 30.0 mg of modified CB and then eluted with 1.0 mol L⁻¹ HCl toward the FAAS instrument. The limits of detection and quantification were found to be 0.20 and 0.66 µg L⁻¹, respectively. Addition and recovery tests carried out in real samples (mineral, tap and saline waters, and cigarette sample) and the analysis of certified reference material (TORT-2, lobster hepatopancreas reference) attested the applicability of proposed method.

Keywords:
nano-carbonaceous material; silanization; Cd²⁺; atomic absorption spectrometry

Material	Surface area / (m² g^-1)	Pore volume / (cm³ g^-1)	Pore diameter / nm
3-MPTMS-grafted CB	455.9	1.02	10.28
Oxidized CB	1010.0	1.09	5.99
CB	1573.0	2.08	6.99

Factor	Level
Factor		(-)			(+)
pH		4.5^a a Acetate/acetic acid buffer;			7.5^b b phosphate buffer. BC: Buffer concentration; EC: eluent concentration; PFR: preconcentration flow rate. The values in parentheses are the real values of factors.
PFR / (mL min^-1)		4.0			8.0
BC / (mol L^-1)		0.01			0.10
EC / (mol L^-1)		1.0			1.5
Assay	pH	PFR	BC	EC	Absorbance / (peak height)	Absorbance / (peak height)
1	+(7.5)	+(8)	+(0.1)	+(1.5)	0.404	0.391
2	-(4.5)	+(8)	+(0.1)	+(1.5)	0.322	0.304
3	+(7.5)	-(4)	+(0.1)	+(1.5)	0.438	0.419
4	-(4.5)	-(4)	+(0.1)	+(1.5)	0.410	0.369
5	+(7.5)	+(8)	-(0.01)	+(1.5)	0.310	0.325
6	-(4.5)	+(8)	-(0.01)	+(1.5)	0.247	0.257
7	+(7.5)	-(4)	-(0.01)	+(1.5)	0.259	0.262
8	-(4.5)	-(4)	-(0.01)	+(1.5)	0.260	0.251
9	+(7.5)	+(8)	+(0.1)	-(1.0)	0.342	0.311
10	-(4.5)	+(8)	+(0.1)	-(1.0)	0.305	0.325
11	+(7.5)	-(4)	+(0.1)	-(1.0)	0.422	0.404
12	-(4.5)	-(4)	+(0.1)	-(1.0)	0.347	0.388
13	+(7.5)	+(8)	-(0.01)	-(1.0)	0.349	0.347
14	-(4.5)	+(8)	-(0.01)	-(1.0)	0.250	0.247
15	+(7.5)	-(4)	-(0.01)	-(1.0)	0.262	0.256
16	-(4.5)	-(4)	-(0.01)	-(1.0)	0.304	0.289

Possible interferent	Variation of analytical signal of Cd²⁺ / %
	Cd²⁺:interferent
	1:1	1:5	1:10	1:50	1:200
Co²⁺	12	9	-16	-12	NI
Zn²⁺	3	10	-7	-7	NI
Ni²⁺	2	8	8	-3	NI
Cu²⁺	12	10	-4	-2	NI
Sb²⁺	-7	3	-4	-2	NI
Pb²⁺	13	-9	7	0	NI
Fe³⁺	-8	-1	2	2	NI
As³⁺	-10	-1	-1	5	NI
Ca²⁺	NI	NI	NI	-6	-2
Ba²⁺	NI	NI	NI	1	-1
Mg²⁺	NI	NI	NI	3	5

Material	Modifier	Preconcentration modality	Eluent	LOD / (µg L^-1)	Linear range / (µg L^-1)	PV / mL	PF	CI / mL	Reference
MWCNT	PAN	off-line	HNO₃ in acetone	0.43	5.0-120.0	200	40.0	5.00	⁴⁹49 Tavallali, H.; Fakhraee, V.; Int. J. ChemTech. Res. 2011, 3, 1628.
MWCNT	oxidized with KMnO₄	off-line	HNO₃	0.15	0.5-50.0	250	-	-	⁵⁰50 Jun-Ping, X.; Qing-Xiang, Z.; Hua-Hua, B. J.; J. Environ. Sci. (Beijing, China) 2007, 19, 1266.
MWCNT	3-MPTMS	on-line	HCl	0.15	1.0-60.0	20	31.5	0.63	⁷7 Corazza, M. Z.; Somera, B. F.; Segatelli, M. G.; Tarley, C. R. T.; J. Hazard. Mater. 2012, 243, 326.
MWCNT	P2AT	off-line	HNO₃	0.30	1.0-100.0	500	-	-	⁵¹51 Nabid, M. R.; Sedghi, R.; Bagheri, A.; Behbahani, M.; Taghizadeh, M.; Oskooie, H. A.; Heravi, M. M; J. Hazard. Mater. 2012, 203, 93.
Graphene nanosheet	reduction of oxidized graphite with hydrazine	off-line	HCl	0.20	0.3-28.8	50	100.0	2.00	⁵²52 Hallaj, R.; Bahar, S.; Babamiri, B.; Zandi, S.; Can. J. Chem. 2014, 92, 62.
Carbon black	3-MPTMS	on-line	HCl	0.20	2.0-40.0	20	37.0	0.54	Present work

Sample	Amount added of Cd²⁺ / (µg L^-1)	Amount found of Cd²⁺ / (µg L^-1)	Recovery / %
Mineral water	0 10 30	0.85 ± 0.08 10.62 ± 0.15 30.26 ± 0.39	- 98 98
Tap water	0 10 30	0.97 ± 0.04 10.39 ± 0.28 30.03 ± 0.19	- 95 97
Saline	0 10 30	0.87 ± 0.04 10.05 ± 0.09 30.21 ± 0.24	- 92 98
Lake Igapó III^a a Located in Londrina, Paraná, Brazil;	0 10 30	0.79 ± 0.04 9.92 ± 0.15 30.10 ± 0.35	- 92 98
Cigarette^b b units in µg g-1. Results are expressed as mean value ± standard deviation based on three replicates.	015^b b units in µg g-1. Results are expressed as mean value ± standard deviation based on three replicates.	1.17 ± 0.07 16.10 ± 0.20	-99

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