Preparation of Modified MWCNT with Dithiooxamide for Preconcentration and Determination of Trace Amounts of Cobalt Ions in Food and Natural Water Samples

Abstract

A fast, sensitive and simple method using multi wall carbon nanotube (MWCNT) coated with dithiooxamide as nanostructure sorbent has been effectively established for extraction and pre‐concentration of trace amounts of cobalt ions before their determination by FAAS (flame atomic absorption spectrometry). Modified MWCNT was synthesized by the reaction of dithiooxamide with functionalized MWCNT. Initially, the surface of MWCNT was oxidized by a mixture of nitric and sulfuric acid and then was functionalized using thionyl chloride, following the ligand was attached to the MWCNT. The properties of nanostructure sorbent were characterized by SEM, BET, TGA, elemental analysis CHNS and FT‐IR techniques. Some effective parameters on extraction and complex formation, such as pH, modified MWCNT dosage, concentration and type of eluent, contacting time, salt effect and sample volume have been optimized. We achieved the calibration graph in linear range of 3–2000 ng mL−1 with limit of detection (LOD) of 0.64 ng mL−1. Relative standard deviation (RSD) for Co (II) ions is calculated to be 2.2 %. The projected technique has been used to assay of cobalt ions at ng mL−1 levels in real samples such as tomato, potato, wheat flour, red beans, oat, tap water, river water and seawater with suitable fallouts.

The synthesis of nitrogen and sulfur co-doped graphene quantum dots for fluorescence detection of cobalt(ii) ions in water

“…It was reported that carboxyl, amino, and thiol groups can interact with cobalt(II) ions via the metal-ligand interaction. 32,36,39,40,42,45,46,57,58 In this work, we observed that the color of the solution changed from colorless to yellow-brown (Fig. S4, ESI ‡), likely due to complexation of Co 2+ with the N,S-GQDs via carboxyl, amino, and thiol groups as shown in Fig.…”

“…A value greater than 5 mg L À1 (0.085 mM) can be toxic. 36 Thus, the procedures for the determination of Co 2+ which have a higher limit of detection than the normal level of Co 2+ in the body are important as they can indicate abnormal excess of Co 2+ . For instance, if Co 2+ levels in serum reach 7 ng mL À1 (0.12 mM), peripheral neuropathy, sensorineural hearing loss, visual loss due to retinal-optic nerve damage, hypothyroidism, and cardiomyopathy are possible.…”

“…Up to the present time, many analysis methods have been developed to detect cobalt ions, for example, electrochemical methods, 36,37 inductively coupled plasma optical emission spectrometry (ICP-OES), 38 and colorimetric methods. 32,[39][40][41] Among these techniques, fluorometry has attracted much interest for metal sensing owing to its simplicity, high sensitivity, rapid response, low-cost detection, and convenience.…”

Ni/Zn Layered Double Hydroxide (LDH) Micro/Nanosystems and Their Azorubine Adsorption Performance

“…For this, extensive varieties of adsorbents with higher uptake ability are available to remove the dyes from wastewater, such as SBA-15/graphene oxide nanocomposites, functionalized SBA-15 [18,19] and ceramic membrane [20]. In addition, many nanomaterials with enhanced porosity and higher specific surface area such as MWNTs [19,21,22] and SBA-15/diphenyl carbazon/SDS nanocomposite [19], Zn/Al LDHs intercalated by dodecylsulfate and carbonate using hydrothermal method without calcination [23] have shown also excellent uptake ability. Synthesized starch coated magnetic nanoparticles and polymeric nanocomposites have been also used for the removal of the unspent dyes from the industrial effluents [24].…”

In-situ hydrothermal synthesis of CNT decorated by nano ZnS/CuO for simultaneous removal of acid food dyes from binary water samples

“…On the other hand, researchers have demonstrated that these chemicals are detrimental to human health 4 . Having continuous usage or absorption via the skin, many synthetic dyes, particularly those with azo functional groups and aromatic rings in their structure, can cause chromosomal damage 5 , allergies 6 , asthma 7 , thyroid tumors 8 , and respiratory illnesses 9 . Research has also shown that daily consumption of foods containing food additives has also been found to lower children's IQ by five points, according to research 10 .…”