Additions and corrections
Supramolecular dispersive liquid–liquid microextraction based solidification of floating organic drops for speciation and spectrophotometric determination of chromium in real samples
Malihe Dehghani Mohammad Abadi, Mahmoud Chamsaz, Mohammad Hossein Arbab-Zavar and Farzaneh Shemirani
Anal. Methods, 2013, 5, 2971–2977 (DOI: 10.1039/C3AY00036B). Amendment published 17th April 2014.
The corrections below should be applied to the above article, these corrections result from an error during the publication process, which led to the incorrect version of the above manuscript being published on-line.
The title of the manuscript should be revised such that the word “on” is placed before “solidification”. The corrected title should thus be: “Supramolecular dispersive liquid–liquid microextraction based on solidification of floating organic drops for speciation and spectrophotometric determination of chromium in real samples.”
In the first sentence of the abstract, grammatical and spelling changes should be made such that the sentence reads: “A novel, sensitive and inexpensive supramolecular dispersive liquid–liquid microextraction method based on the solidification of floating organic drops (SM-DLLME-SFO) is proposed for the speciation and preconcentration of trace quantities of chromium as a precursor to its determination by UV-Vis spectrophotometry for the first time.”
In the Introduction section, a grammatical change should be made in the first full sentence of page 1, column 2; the revised sentence should thus read: “However, there are some shortcomings in these techniques e.g. long extraction times and high stirring rates causing the suspended organic drop to become unstable in SDME; the long pretreatment time and creation of air bubbles on the surface of the HF decreases the transport rate and also manual cutting of the membrane resulting in poor reproducibility in HF-LPME; hazardous organic solvents with densities greater than water are also employed in the DLLME method.”
A grammatical change should be made in the penultimate sentence of page 1, column 2; the sentence should thus read: “Coacervates are water immiscible liquids which are separated out from the bulk of colloidal solutions with the aid of dehydrating agents.”
In the fourth full sentence of page 2, column 1, a comment regarding the convenience of the method should be added, such that the sentence reads: “The method, beside the advantages of DLLME (simplicity of operation, high recovery, very short extraction time due to the very large surface area between the organic and aqueous phases), benefits from other useful factors such as employing nontoxic, in flammable and less expensive decanoic acid as an extraction solvent whereby it is handled when dissolved is very convenient and does not have the limitations associated with applying solvents with densities higher than water.”
In the subsection “Determination of chromium content”, the third sentence should be revised for clarity to read: “The beaker was covered with a watch glass and heated gently (50 °C) for about 15 min to complete the oxidation process.”
In the subsection “Sample preparation”, the fourth sentence of the first paragraph should be replaced in its entirety by the following: “It was followed by addition of 6 mL of concentrated nitric acid and the solution was heated to almost dryness. In this process nitric acid was vaporized and most of sulphuric acid was removed from the bulk of solution. The final solution was then treated with water to give a clear solution and finally made to 100 mL with deionized water.”
In the second paragraph of the subsection “Sample preparation”, there is a spelling error in the name of the city from which the well waters were sourced. The correct spelling is “Mashhad”.
In the section “Results and discussion”, there is an error in the final term of the first equation. 8H2SO4 should be replaced by 8H2O, such that the equation reads:
2CrO42− + 3H4L + 8H+ → Cr(III)(HL)2+ + Cr3+ + H2L + 8H2O
At the end of the second paragraph of the section “Results and discussion”, the following sentence should be added: “Each optimization experiment was carried out for three replicates.”
In the subsection “DPC and SDS concentrations”, the final sentence should be altered for clarity such that it reads: “Absorbance increased up to 0.005% (w/v) and was slightly decreased afterwards and hence 0.01% (w/v) was chosen as the optimum value.”
The current Figure 2 should be replaced by the following figure, in which error bars have been added.
Fig. 2:
The unit of concentration in the captions to Figures 2, 3, 4 and 5 should be expressed as mol L−1 rather than M; the relevant statement in each figure caption should therefore read: “volume of 1 mol L−1 H2SO4, 0.5 mL;”
In the second sentence of the subsection “Amount of extraction solvent”, the quantity of decanoic acid mentioned should be amended and some further detail added; the sentence should therefore be revised as: “The results show that the absorbance increased with the increase of decanoic acid up to 70 mg and then nearly levelled off to 100 mg and after that it started slightly to diminish (Fig. 3).”
The current Figure 3 should be replaced by the following figure, in which error bars have been added.
Fig. 3:
In the subsection “Volume of disperser solvent”, a grammatical change should be made to the third sentence such that it reads: “The results indicate (Fig. 4) that the maximum absorbance signal was obtained for 0.6 mL of THF.”
In the subsection “Ionic strength”, the upper quantity of NaNO3 is incorrect. The sentence should be amended to read: “To investigate the influence of ionic strength on the microextraction efficiency, various experiments were performed by adding different amounts of NaNO3 (0–20% w/v) to the standard solution (25 mg L−1 of Cr(VI)), while other experimental conditions were kept constant.”
The current Figure 4 should be replaced by the following figure, in which error bars have been added.
Fig. 4:
The current Figure 5 should be replaced by the following figure, in which error bars have been added and the values on the x axis have been corrected.
Fig. 5
In the subsection “Interference studies”, the third sentence should be replaced in its entirety by the following: “An ion is considered to interfere if it causes more than ±5% relative error in the determination of Cr(VI).”
In Table 1, the heading of the second column should be amended to read “Interference/Cr(VI)ratio”. Additionally, the percentage recovery given in the third column for Cd2+ should be amended to 94%.
In the subsection “Analysis of standard reference material and water samples”, the number of determinations upon which the results are based should be quoted in the final sentence. The sentence should thus be replaced by the following: “The results are given in Table 2, which are based on three determinations”.
In the subsection “Comparison to other methods”, the grammar of the second sentence should be altered such that the sentence reads: “In the recommended method, a better LOD was obtained for Cr(VI) ions in comparison with other methods”.
In the fifth sentence of the subsection “Comparison to other methods”, an abbreviation for CPE should be added such that the sentence reads: “In comparison with cloud point extraction (CPE) this method requires no heating step, and the extraction time would be greatly decreased.”
In the third column of Table 3, the two entries “CCL4” should be corrected to read “CCl4”.
The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.
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