The Estimation of Small Metal Traces of Cd (Ii) From the Alloy and Water Effluents using Fast and Accurate Extractive Spectrophotometric Method with Newly Developed DBA Reagent

Experimental research was reported on the extraction and the spectrophotometric determination of minute quantities of Cd(II), using a fresh novelligand 2, 4-dimethyl -3H- 1, 5 benzodiazepine (DBA) from given sample of alloy. In this work, thefresh ligand was developed and its characterization was conducted using mass spectrophotometer and IR, NMR. A developed analytical ligand (DBA) when reacts with cadmiumproduces colored compound, this red colored complex, maintained at constant pH 8.9 and again extracted usingn-butanol as a selected solvent. Beers law is also validated in the selected concentration range. The optimum parameters like absorption maxima, molar extinction coefficient and sandell’s sensitivity to the red compound were also reported to be 450 nm,1960 L mol -1 cm -2 and 0.01879μgcm -2 , respectively. A prepared analytical ligand DBA is found to be effective and efficiently employed for determination of small quantities of Cd (II) metal ions.


Introduction
The accurate identification of cadmium in the samples of industrial liquid effluents, medical, pharmaceutical samples are important because of its toxicity and contribution towards the number of diseases and deaths (Fergusson et.al 1989 andVenugopal et.al.1979).All these above findings indicates that even a small traces of cadmium metal has an adverse effects on human health, Therefore, an accurate and simple identification of this cadmium metal at trace level is challenging task.

Analytical
Table 1 presents the comparison between the current and earlier spectrophotometric extraction methods.
The aim of this research isto extract traces of Cd (II) with newly developed DBA ligand.Efforts have been also done to determine Cd (II) in the small quantities from synthetic and alloy samples.Besides, the effects of pH, wavelength, and choice of optimum molar ratio on the extraction of Cd (II) have been also conducted.

Experimental Techniques Instruments used
In this work,a calibrated Ultra violet visible spectrophotometer (Model: Shimadzu 2450, 10 mm quartz cell) was used in the measurement of absorbance and pH measurement were done with a calibrated digital pH meter (Make: Elico LI-120).The important experimental parameters have been reported and are presented in Table 2 Formulation of DBA Ligand A reaction between one mole of o-phenylenediamine and one moles of Acetyl acetonein presence of Ethanol (solvent) were carried out for formulation of novel ligand (Fig. 1).The product achieved is then heated in water bath at constant temperature of 100 o C in a round bottom glass flask, maintain under total reflux for 2 hrs.The acquired solution is then transferred in ice bath to produce crystals.A resultant solid productis then further recrystallized by using solvent as ethanol.After the reagent (M.P. 274 o C) is synthesized, it is then characterized by NMR and IR spectrum and easily employed in the determination small Cd (II) traces using spectrophotometry extraction.A stock solution of devisedligand in the 0.05% concentration in a methanol is ready for further investigations.The newly devised reagent DBA and Cadmium have strong complex formation tendency due to presence of electron donor nitrogen atom present in the reagent.

pH selection for Extraction
In this study, various Buffer solutions with varying pH was used for Cd (II) extraction, andmolar ratio between organic and aqueous phase was constantly monitored at 1:1.The impact of pH on the variation of absorbance as indicated in the figure 2.A same figure depicts that the values of absorbance are increasing with rise in pHand attains a highest magnitude at pH 8.9 and further increase in pH beyond the 8.9, the absorbance decline sharply.
Hence, the buffer of pH 8.9 was selected in future research work.

Method of Experiment
The mixtureof 1 cm 3 solution of cadmium sulphate with 0.05% DBA novel ligand in methanol was prepared.The solution pH was constantly monitored at 8.9 with slowly addition of buffer solution (A buffer was prepared by mixing 1 mole L -1 of NH 4 OH with 1.8 mole L -1 of NH4Cl).This solution is then subjected to gravity separation in a separating glass funnel with additional of 10 mln-butanol.Due to effect of gravity the phases are separated in to organic and aqueous phase.Out of these two phases, an organic phase placed under a UV Spectrophotometer at wavelength of 450 nm, to record the absorbance.

Formulation of Calibration Curve
As discussed above, the similar procedure was followed in the development of calibration curve.The Cd (II) samples of various concentrations (1-10 ppm) were prepared, mixed with the DBA reagent, and extracted with n-butanol.Further, its absorbance measured, and Calibration curve was developed (Fig. 5).

Choice of Mole Ratio of Cd (Ii) to Novelligand
The perfect selection of molar ratio of Cd (II) to DBA ligand, using different methods has been predicted and presented in Figure 6.The Job's continuous variation is one of the commonly used methods in most of the cases to fix up the composition ratio between metal ions and analytical reagent.The result achieved from Job's continuous variation method was further verified using other recommended methods namelyslope ration and mole ratio.In this work, appropriate mole ratio of Cd (II) to DBA ligand was fixed to be 1:1.

Fig. 5: Calibration curve of Cd (II) Influence of Diverse Ions
To validate the potentialvaried applications of the developed analytical techniques, the impact of various diverse ions are experimentally examined by carrying out determination of 100 µg /mL Cd (II) ions with a small quantity of diverse ionsolutions, using the developed experimental methodology.The limits of tolerance between higher value of actual absorbance of given ions and value expected for plain Cd (II) ion was set to be within ±2% discrepancy.The results clearly depicts that utmost of the metal ions can be accepted in considerable set limit of tolerance (Table 3).The interference effects of these ions are suppressed with several agents in the actual determinations of Cd (II), as indicated in the Table 4.

Different Analytical Reagents for Cd (Ii) Determination and their Drawbacks
Table 5 shows the assessment between various analytical reagents used by the previous workersand DBA ligand forthe estimation of Cd(II).A present experimental work confirms thatthe developed DBA reagent seems to be betterthan that of some reported reagents.

Testing of Precision and Accuracy
The precision of the present method was determined by testing different concentrations of cadmium (each sample was analyzed minimum at least three times).The relative standard was in the limit of 0 -2% confirms that this method is highly precise and reproducible, the average percentage extraction in tested samples were indicated in Table 5. PATIL, Curr.World Environ., Vol. 17 The relative standard deviation is found to be in the limit of 0 to 2 % The % extraction and % relative standard deviation Figure 7 presents the % Extraction and % relative standard deviation with various samples tested.The % extraction was found to be 98.5, 99.7 and 96 % for solder alloy, Nichrome alloy and drinking water samples respectively.Whereas the % standard deviations were observed to be 1.5,1,03 and 1.3 for solder alloy, Nichrome alloy and drinking water samples respectively.

Applications of Present Work
The present work demonstrates the development of new fresh analytical ligand for effective and efficient estimation of Cd (II) metal ions from given mixture.This analysis method was employed for estimation of Cd (II) traces in an area like alloy, water treatment, food industries.The newly developed analytical ligandis appears to be bestover the other reagents.PATIL, Curr.World Environ., Vol.17(3) 815-825 (2022)

Conclusion
The present experimental investigations demonstrates that a newly synthesized, fresh analytical reagent was showed to be accurate, cheap, less time consuming for spectrophotometric estimation of Cd(II).
Advantages of the developed method are as follows:-• Reagent is easily synthesized and purified.

Fig. 2 :
Fig. 2: pH Solvent Selection for Extraction In this laboratory experiments various organic solvents were tested to forright selection of extraction solventand experimental results achieved to the various solvents are summarized in Figure 3. From presented results, n-butanol was found to be best solvent for extraction of Cd (II).

Fig. 6 :
Fig. 6: Choice of molar ratio of Cd (II) to novel reagent

Table 2 : Important Experimental variables Parameter maintained Remark
Stock SolutionThe stock solutionof 100 ppm concentration of Cd +2 was ready by adding 0. 2282mg of cadmium sulfate (3 CdSO 4 , 8 H 2 O) (Merck) crystals in a 100 ml distilled water.Moreover, additional sets of dilute solutions were made by adopting standard operating procedure.

Table 6 : Applications of present study Sr. No. Samples Cd(II) determined Cd(II) determined % extraction % standard by standard method by present method Deviation
• The process of extraction is one step, fast and accurate.• It require very low reagent concentration of analytical reagent • The developed method used DBA reagent by maintaining constant pH 8.6 is seems to be better as compared to earlier method of 1,10-phenanthroline analytical reagent with varying pH 8.2 to 9.8 • In this developed method most of the ions do not interfere in the extraction process.• This developed method possesses main benefits like simple, single step, fast, accurate and cost effective.Hence, it can be used forestimation of small traces of Cd(II)from the alloy and water effluents.