Paper
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Analytical application
Acknowledgements
Intra-day precision was determined by performing four
repeated analysis of the three standard Cu2+ solutions on the
same day under the same conditions. Inter-day precision of the
method was assessed by carrying out the determination of Cu2+
in standard solutions on three different days in the same
laboratory. The mean, standard deviation and relative standard
deviation was determined in order to assess the precision of the
method (Table 6).
This study was supported by the Scientic Grant Agency VEGA
of the Ministry of Education of the Slovak Republic and the
Slovak Academy of Sciences (Grant No. 1/0253/16). A. Tupys
would like to thank to the International Visegrad Fund for
providing a ve-month scholarship (Grant No. 51501721).
Notes and references
To check the practicability of the suggested method with
BnTAN, the certied reference material SPS-WW2 Batch 113 was
used. According to the certicate, the concentration of Cu(II) in
this reference material for measurement of elements in waste-
waters was 2.000 ꢃ 0.010 mg Lꢀ1. The result for the determi-
nation of Cu(II) using the proposed method (n ¼ 5, P ¼ 0.95)
showed that the amount of copper in this material is 1.959 ꢃ
0.088 mg Lꢀ1 (RSD ¼ 3.6%). This corresponds well with the
reference documentation and proves the practical validity of the
technique.
As a supplementary conrmation of the applicability of the
method, model samples containing various quantities of Cu(II)
were prepared and tested. Among them were tap water and river
water samples. As can be seen in Table 7, the repeatability of the
technique is good (1.32–1.88%).
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Conclusions
This work presents a new approach for the determination of
Cu(II) in water samples. The possible application of two azo dyes
in the analysis of copper was investigated and ligand 1-[(5-
´
´
12 A. Rıos, M. De Dolores Luque Castro and M. Valcarcel,
benzyl-1,3-thiazol-2-yl)diazenyl]naphthalene-2-ol
(BnTAN)
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dye BnTAN in the presence of Triton X-100 has been developed.
According to the results of the intra-day and inter-day deter-
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A low LOD value of
0.044 mg Lꢀ1 enables the determination of Cu2+ ions in envi-
ronmental samples. The proposed method was successfully
used in the analysis of different water samples and a reference
material containing Cu(II). This technique offers a green alter-
native to a previously published extractive technique28 that
applied 25 mL of toluene. The combination of the spectropho-
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advantages in accordance with the requirements of green
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reagents; (2) no need to use toxic organic solvents; (3) reduced
risk of the analyte loss and sample contamination; (4) better
accuracy and precision. Furthermore, the total sample
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which is high enough in comparison with other methods.
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Conflicts of interest
24 S. L. C. Ferreira, N. M. L. Araujo, A. B. Santos, A. F. Dantas
and A. C. Spinola Costa, Mikrochim. Acta, 1995, 118, 123.
There are no conicts to declare.
This journal is © The Royal Society of Chemistry 2018
RSC Adv., 2018, 8, 15940–15950 | 15949