**3.10. Analytical applications**

302 Polyurethane

Microcrystalline benzophenone

Microcrystalline naphthalene

Octylsilane (RP-8) cartridge

Amberlite XAD-7 resin Modified Chitosan

**3.9. Interference study** 

Ca2+, Mg2+, Cl-

ng L**-1**

**3.8. Figure of merits of the PQ+.Cl- immobilize PUFs packed column** 

versus bismuth (III) concentration (C) has the regression equation:

HG-ICP-OES ICP-MS

and electrochemical techniques for bismuth determination in water

The LOD, LOQ, enrichment and sensitivity factors and relative standard deviation, (RSD) under the optimized conditions were determined. The plot of signal intensity of ICP- OES (I)

According to IUPAC [46, 47], the LOD = *3Sy/x*/*b* and LOD = *10Sy/x*/*b* were 0.9 and 3.01 ngL-1, respectively (V sample = 100 mL) where, Sy/x is the standard deviation of *y*- residual and *b* is the slope of the calibration plot [46]. The LOD of the developed method is much better than direct measurement by ICP – OES (5.0 μg mL-1). The enrichment factor (Fc = Vs,b /Ve,v) was defined as the ratio between the volume of analyte sample (Vs,b = 1000 mL) before preconcentration and the eluent volume (Ve,v) after retention and recovery. An average value of Fc of 100 was achieved. The sensitivity factor (the ratio of the slope of the preconcentrated samples to that obtained without preconcentration) was 33.3. The RSD of the method for the determination of standard bismuth (III) solution (50 μg L-1) was ± 2.5% (n= 5) confirming the precision of the method. The figure of merits of the developed method were compared satisfactorily to the reported methods e.g. ICP-OES [45], spectrophotometric [47] and electrochemical [49 -51] (Table 5) in water confirming the sensitivity and applicability of the proposed method. The LOD of the method could be improved to lower values by prior pre concentration of bismuth (III) species from large sample volumes of water (>1.0L). Thus, the method is simple and reliable compared to other methods [50 -52].

SPE Technique Linear range,μgL-1 LOD, μgL-1 Reference

PQ+ .Cl – loaded PUFs ICP – OES 0.01 – 100 2.7\* Present

**Table 5.** Figure of merits of the developed and some of the reported SPE coupled with spectrochemcal

The influence of diverse ions relevant to wastewater e.g. alkali and alkali earth metal ions

concentrations (0.5 -1.0 mg/ 100 mL sample solution) on the sorption of 10 μg bismuth (ІІІ)

, Zn2+, Mn2+, Cu2+, Hg2+, Fe2+, Fe3+, Pb2+, Al3+, Ni2+, Co2+ and nitrate at various

UV – Vis 0 – 2 X104 \_\_\_ 34

DPP 180 – 135x102 55 35

ASV 10.5 – 1000 0.73 36

Up to 100 0.02

0.1\*

6 15

work

I= 4.19 x103C (ng L-1) + 12.96 (r=0.9995) (21)

The validation of the developed method was performed using the certified reference materials (CRM-TMDW). Good agreement between the concentration measured by the proposed method (8.9 ± 0.9 μgL-1) and the certified value (10.0 ± 0.1 μgL-1) of the total bismuth was achieved confirming the accuracy of the method for trace analysis of bismuth in complex matrices.

The method was also applied for the determination of bismuth in wastewater samples (1.0 L) after digestion and percolation through the PUFs packed columns as described. Complete retention of bismuth was achieved as indicated from the ICP-MS analysis of bismuth in the effluent. The retained [BiI4] species were recovered with HNO3 (10 mL, 3.0 mol L-1) and analyzed by ICP-OES. Various concentrations of bismuth (III) were spiked also onto the tested wastewater samples and analyzed (Table 6). Bismuth (ІІІ) determined by the method and that expected (Table 6) in the tested water samples revealed good recovery percentage (98.4± 2.3 – 104 .3 ± 2.8 %) confirming the accuracy and validation of the method.


\* Average recovery of five replicates ± relative standard deviation.

**Table 6.** Recovery study applied to the analysis of bismuth in wastewater by the developed method

The selectivity of the procedure was further tested for the analysis of bismuth in Red sea water at the coastal area of Jeddah City, Saudi Arabia following the standard addition. as described..The results are summarized in Table 7. An acceptable recovery percentage of 107.01 ±3.5 -108.1 ±2.7 was achieved confirming the selectivity, accuracy and validation of the method.


\* Average recovery of five replicates ± relative standard deviation

**Table 7.** Recovery test for bismuth in sea water by the developed method
