Determination of bismuth in different samples by dispersive liquid–liquid microextraction coupled with microvolume β-correction spectrophotometry

Journal of Molecular Liquids 212 (2015) 635–640

Contents lists available at ScienceDirect

Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq

Determination of bismuth in different samples by dispersive liquid–liquid microextraction coupled with microvolume β-correction spectrophotometry H.M. Al-Saidi a, M.A. Abdel-Fadeel b, A.Z. El-Sonbati b, A.A. El-Bindary b,⁎ a b

Chemistry Department, University College in Al–Jamoum, Umm Al-Qura University, Makkah 21955, Saudi Arabia Chemistry Department, Faculty of Science, Damietta University, Damietta 34517, Egypt

a r t i c l e

i n f o

Article history: Received 7 July 2015 Received in revised form 4 October 2015 Accepted 7 October 2015 Available online 11 November 2015 Keywords: Microvolume β-correction spectrophotometry Liquid–liquid microextraction

a b s t r a c t A novel microvolume β-correction spectrophotometric method was proposed for the sensitive and selective determination of bismuth coupling with dispersive liquid–liquid microextraction (DLLME). The basis of the method is a quantitative colorimetric reaction between Bi3+ ions and dithizone, and the orange–brown colored complex of Bi(HDz)3 was then extracted into CCl4 phase by DLLME. Parameters related to the efficiency of microextraction, such as pH, complexant concentration, the volume ratio of disperser solvent and extraction solvent were discussed and optimized in detail. Under the optimized conditions, the real absorbance was in proportion to bismuth concentration in the range of 3–100 μg·L−1 with a correlation coefficient (R) of 0.993. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.54 μg·L−1 and 1.80 μg·L−1, respectively. Good recoveries of bismuth were obtained in the range of 96.3–103.6% in different real samples confirming the accuracy of developed procedure and its independence from matrix interference. © 2015 Elsevier B.V. All rights reserved.

1. Introduction Bismuth and its compounds have several applications in our daily life. In medicine, bismuth subsalicylate is used as cytoprotective agent for the treatment of gastritis, while, bismuth citrate is recently employed in the preparation of cosmetic and hair dyes. In industry, bismuth compounds are used as catalysts in the synthesis of methanol, and in metallurgical process for production of low melting alloys [1–4]. Therefore, the appearance of bismuth in environment become significant. Until recently, it was believed that bismuth is nontoxic; however, some recent researches have reported that bismuth compounds after oral intake enter the nervous system of mice, in particular, in motor neurons, therefore, bismuth species may be included in the list of potential toxins [5]. In last years, many analytical methods e.g. atomic absorption spectrometry (AAS) [6], hydride generation atomic absorption spectrometry [7], electro thermal atomic absorption spectrometry [8], cathodic and anodic adsorptive stripping voltammetry [9–11], hydride generationatomic fluorescence spectrometry (HG-AFS) [12], inductively coupled plasma atomic emission spectrometry (ICP-AES) [13] and inductively coupled plasma mass spectrometry (ICP-MS) [14] have been reported for the determination of bismuth in different samples. However, the

⁎ Corresponding author. E-mail address: [email protected] (A.A. El-Bindary).

http://dx.doi.org/10.1016/j.molliq.2015.10.015 0167-7322/© 2015 Elsevier B.V. All rights reserved.

low cost and simple techniques like spectrophotometry are still preferred because of easy to use and availability in many laboratories. The pretreatment of sample is sometimes necessary prior to the application of such technique for overcoming sample matrix interference and preconcentration of analyte. Liquid–liquid extraction (LLE) is one of the most widely used pretreatment techniques for separation and preconcentration of both organic and inorganic species from variety of samples [15–17]. However, this technique has number of disadvantages like emulsion formation and the use of large volumes of toxic organic solvents. Therefore, its use became limited in recent years. Thus, microextraction techniques, based on minimization of toxic organic solvents volume, and free — solvent techniques e.g. cloud point extraction (CPE) has become commonly employed as alternatives to LLE. Among microextraction methods, dispersive liquid–liquid microextraction (DLLME) introduced by Assadi et al. in 2006 has found wide applications to the analysis of heavy metals, pesticide residues and so on [18–20] due to easy application and excellent analytical performance compared to other microextraction techniques. However, when chromogenic reagent and its complex with analyte have strong trend to dissolve in organic phase, the sensitivity of DLLME combined with UV–Vis spectrophotometry reduces dramatically due to the interference of the excess of chromogenic reagent with the analyte at λmax. This interference may be solved employing the β-correction spectrophotometry to calculate the real absorbance of the complex [21–25]. Therefore, the method developed in the present work is based upon DLLME coupled

636

H.M. Al-Saidi et al. / Journal of Molecular Liquids 212 (2015) 635–640

with β-correction spectrophotometry for the determination of bismuth in variety of samples. 2. Experimental 2.1. Reagents and materials Unless otherwise stated, all chemicals and solvents used in the present work were of analytical reagent-grade quality and were used without further purification. A stock solution of bismuth ions (1000 μg·mL−1) was prepared from Bi(III) nitrate (Aldrich Chemical Co. Ltd., Milwaukee, WC, USA). More diluted standard (0.01–10 μg·mL−1) solutions were prepared by diluting the stock solution with deionized water. A stock solution of dithizone (Fluka A G) with concentration (5 × 10−3 mol·L−1) was prepared by dissolving the required weight in carbon tetrachloride (100 mL). Stock solutions (1000 μg·mL−1) of metal ions employed to test the selectivity were prepared from their nitrate or chloride salts in deionized water. A series of Britton–Robinson (BR) buffer of pH (2–11), and mixture of NaOH/H2SO4 to adjust the pH of the aqueous solution in the range of 2–11 were prepared. The organic solvents used either as extraction solvents or disperser solvents were purchased from Merck (Darmstadt, Germany). 2.2. Apparatus All spectrophotometric measurements were recorded by Perkin– Elmer UV–visible (190–1100 nm) spectrophotometer (model Lambda 25, USA) with a quartz micro cell (45 mm high, internal width 4 mm and path length 10 mm) with 800 μL internal capacity. A digital micropipette (Volac) and an Orion pH meter (model EA 940) were employed for the preparation of standard bismuth and test solutions and pH measurements, respectively. A digital sensitive balance ADP 110 L with three decimal numbers. Safety-Head centrifuge (Clay Adams) with 6000 rpm has been used for collecting fine droplets. Deionized water was obtained from Milli-Q Plus system (Millipore, Bedford, MA, USA) and was used for preparation of solutions. A Perkin–Elmer ICP-MS Sciex model Elan DRC II (California, CT, USA) was used as a reference procedure for bismuth determination at the operational parameters shown in Table 1. 2.3. Recommended analytical procedure Various concentrations of Bi3 + ions in the range of 3–100 μg·L−1 were adjusted to pH 5 by mixture of H2SO4/NaOH and then transferred into 15 mL calibrated conical tube. All solutions were diluted to 10 mL with deionized water. Then, mixture of 150 μL of dithizone (1 × 10− 4 mol·L− 1) dissolved in CCl4 and 500 μL of methanol was rapidly injected using a 2.0 mL syringe. The extraction tube was closed and shaken by vortex until the solution became turbid, then the extraction mixture was centrifuged for 2 min at 3000 rpm. After phase separation, the bulk aqueous phase solution was removed by a syringe, while the

sediment phase was diluted to 0.5 mL with methanol and subjected to absorbance measurements at 610 (λ1) and 497 nm (λ2) against reagent blank. Calibration plot of Bi3+ ions concentration versus the real absorbance calculated by dual wavelength (λ1 = 610 and λ2 = 497 nm) β-correction spectrophotometric method was used for all subsequent measurements to determine bismuth in real samples and test the selectivity of method. 2.4. Sample preparation 2.4.1. Water samples Three different water samples, including; tap water collected from the laboratories of Chemistry Department, King Abdulaziz University, Jeddah City, KSA, and drinking water, commercially available in Saudi market, and wastewater sample taken from the waste water treatment plant at King Abdulaziz University, Jeddah City KSA, were filtered through 0.45 μm cellulose membrane filter prior to the analysis and stored in LDPE sample bottles (250 mL) at 5 °C in the dark. Few drops of KCN & NaF (0.1% m/v) were added into all samples solutions to overcome potential interferences prior to the application of recommended procedure. 2.4.2. Human hair Human hair sample was washed with water, immersed in acetone for 45 min, and then in a 1% neutral scouring agent for 3 min, the sample was rinsed with water and deionized water several times, and then dried at 110 °C. 0.5 g of sample dried was weighed accurately, digested by 30.0 mL of a mixture of HClO4 and HNO3 (1:8 v/v). The solution obtained was evaporated until dryness, and then several drops of H2SO4 (1:1 v/v) were added to dissolve the residue. The solution was transferred to a 100.0 mL measuring flask, and diluted to the mark with deionized water. An aliquot of solution was selected for applying recommended procedure mentioned above. 2.4.3. Drug sample A tablet of De–Nol drug containing 120 mg bismuth as bismuth tripotassium dicitrate and used for the treatment of peptic ulcers was dissolved in 10 mL of perchloric acid and the solution was then evaporated nearly to dryness. The residue was dissolved in deionized water containing 1 mL of HNO3, and then diluted to 100 mL in measuring flask. The solution was diluted to 100-fold prior to the analysis by the recommended procedure. 2.5. Statistical treatment All experiments were carried out three times and the data was expressed as mean ± SD (standard deviation). The statistical F and T tests were used for evaluation of the results statistically. Treatment of data and statistical analysis (average value and recovery) were carried out employing datasheets prepared by Microsoft Excel 2010. 3. Results and discussion

Table 1 ICP-MS operational conditions for bismuth determination. Parameter

Value

ICP RF power (W) Nebulizer gas flow (L.min−1) Plasma gas (Ar) flow rate (L·min−1) Auxiliary gas (Ar) flow rate (L·min−1) Lens voltage (V) Analog stage voltage (V) Pulse stage voltage Quadrupole rod offset std. Discriminator threshold Cell path voltage std. (V) Cell rod offset (V) Atomic mass (am) Sample flow rate, mL

1100 0.94 15 1.2 0.9 −1750 800 0 22 −13 −18 209 93

3.1. Application of β-correction spectrophotometry It is well-known that, once mixing dithizone (H2Dz) with Bi3+ ions in aqueous media, the orange–brown colored complex of Bi(HDz)3 is developed immediately [26]. The electronic spectrum of the reagent H2Dz recorded after applying DLLME against methanol showed one well-defined peak at 610 nm (Fig. 1A), while, the spectrum of the Bi(HDz)3 extracted by DLLME and recorded against methanol showed one absorption peak at 495 nm with molar absorptivity (ε) of 4.44 × 105 L·mol−1·cm−1 (Fig. 1B). However, Fig. 1 demonstrated a strong overlap between electronic spectra of H2Dz and Bi(HDz)3 at 495 nm (λ2), and therefore, the excess of H2Dz in organic phase will cause severe spectral interference decreasing the sensitivity of

H.M. Al-Saidi et al. / Journal of Molecular Liquids 212 (2015) 635–640

Fig. 1. Electronic spectra of the reagent H2D2 and its complex with Bi3+ after applying DLLME at the optimum conditions. Curve A represents the spectrum of the reagent blank against methanol; curve B is the electronic spectrum of Bi(HDz)3 recorded against methanol; curve C is absorption spectrum of Bi(HDz)3 recorded employing reagent blank as a reference.

spectrophotometric method based upon this reaction. Although use of reagent blank (conventional spectrophotometry) reduces the effect of such interference, the sensitivity will be improved dramatically after the application of the β-correction spectrophotometry to calculate real absorbance (Ac) of Bi(HDz)3 at λ2 [21–25]. Thus, the β-correction technique is used for the first time with DLLME in the present work to improve the sensitivity of DLLME-spectrophotometry. To calculate Ac, the spectrum of Bi(HDz)3 complex should be recorded against regent blank after applying DLLME, and Ac is then calculated using the minimum and maximum absorption peaks of Bi(HDz)3 at 610 (λ1) and 495 nm (λ2), respectively as shown (Fig. 1C) and with the aid of the following equation [21–25]: Ac ¼

ΔA  ΔA΄ 1  αβ

ð1Þ

where, the spectrophotometric parameters α, β were also calculated employing the equations: β¼

Ao 0

Ao

ð2Þ

0

α¼

Aα Aα

ð3Þ

where, ΔA’ and ΔA, are the absorbance's of the Bi(HDz)3 versus reagent blank at λ1 and λ2 respectively. The values of A'o and AO represent the absorbance's of the blank solution against methanol at λ1 and λ2 and A'α and Aα are the absorbance's of the Bi(HDz)3 complex versus

Fig. 2. The influence of pH on extraction efficiency of Bi3+ ions as a function of absorbance of organic phase diluted after applying DLLME. Bi3+ concentration = 150 μg·L−1.

637

Fig. 3. The influence of the extractant type on DLLME efficiency. Condition of DLLE: Bi(III) = 150 μg·L−1; dithizone = 1.5 μmol·L−1; disperser solvent = 0.5 mL of methanol; pH = 5.

methanol at λ1 and λ2, respectively. Based on Eqs. (2) and (3), the parameter β calculated from curve (a) was equal to 0.566 while, the numerical value of α calculated from curve (2) was 0.285. 3.2. Optimization of parameters Optimization of experimental parameters affecting the extraction efficiency of DLLME combined with β-correction spectrophotometry was carried out employing a step-by-step approach in which each factor is varied sequentially. This approach is simple and effective when the number of influencing factors is relatively little. 3.2.1. Effect of pH The pH of the sample solution is one of the most important factors affecting the efficiency of DLLME. Therefore, the real absorbance of the organic phase after applying DLLME was measured using Britton– Robinson buffer (2–11), and mixture of H2SO4/NaOH. As demonstrated in Fig. 2, the maximum absorbance was achieved over wide range of pH (2–5), therefore, this provides wide pH interval to work which is one of proposed method features. The fact that the formation of the complex was incomplete in more acidic media (pH b 2) due to competition of hydrogen ions with Bi3+ for reaction with H2Dz reagent. While, in alkaline media (pH N 6), the extraction recovery was low owing to precipitation of bismuth hydroxide. Moreover, the absorbance was more stable when using mixture of H2SO4/NaOH compared to Brittone–Robinson buffer. Therefore, the pH of 5 adjusted using mixture of H2SO4/NaOH was selected as the optimum value for subsequent work. 3.2.2. Effect of type and volume of extractant For obtaining high efficiency of DLLME, careful attention should be paid to the selection of the type and volume of the extractant. The

Fig. 4. The effect of disperser solvents on the absorbance of diluted organic phase after DLLME. condition of DLLE: Bi(III) = 150 μg·L−1; dithizone = 1.5 μmol·L−1; extractant = 150 μL of CCl4; pH = 5.

638

H.M. Al-Saidi et al. / Journal of Molecular Liquids 212 (2015) 635–640 Table 3 Analytical characteristics of DLLME-spectrophotometry (A) and DLLME-β-correction spectrophotometry (B).

Fig. 5. Effect of chelating reagent on the absorbance of bismuth(III).condition of DLLME: Bi(III) = 150 μg·L−1; disperser solvent = 0.5 mL of methanol; extractant = 150 μL of CCl4; pH = 5.

solvents used in normal DLLME as extraction solvent should have lower solubility in water and high ability of extraction of analyte. Thus, dichloromethane, chloroform and carbon tetrachloride were investigated as extractant and in the presence of methanol as disperser solvent. As shown in Fig. 3, the highest corrected absorbance was observed using carbon tetrachloride. This behavior is most likely attributed to the low solubility of CCl4 in water (0.08 g/100 mL) compared to other used solvents and the high partition coefficient of Bi(HDz)3 complex between CCl4 and water which is equal to 2.5 × 104. Therefore, CCl4 was selected as an extractant in the recommended procedure. It should be noted that the final organic phase obtained after centrifugation will increase with increasing the extractant volume, but enrichment factor (EF) will decrease. Thus, the optimal extracting solvent volume should ensure both high EF and enough volume of the sedimented phase for the subsequent analysis after centrifugation. Therefore, different volumes of carbon tetrachloride were employed with fixed volume of methanol as disperser solvent for extraction of 150 μg·L−1 bismuth(III) ions. The absorbance intensity increased by increasing the volume of CCl4 to 150 μL and then remained approximately constant by further increasing. Thus, 150 μL of CCl4 was used in the recommended procedure. 3.2.3. Effect of type and volume of disperser solvent In DLLME, the selection of disperser solvent is critical and it affects strongly on the efficiency of extraction. In fact, miscibility of disperser with organic phase (extraction solvent) and aqueous phase (sample solution) is the most important point for the selection of a disperser. Thus, proper solvents including acetone, methanol, ethanol and acetonitrile were studied to select the best disperser solvent. The results shown in Fig. 4 proved that methanol was the best disperser solvent for the extraction of bismuth. Therefore, the effect of the volume of methanol on the extraction efficiency was investigated in the range of 0.1– 1.5 mL and using 150 μL CCl4 as the extracting solvent. The obtained results showed that in the case of using 0.5 mL of methanol, the highest absorbance was attainable. 3.2.4. Effect of H2Dz concentration It is highly important to establish the minimal reagent concentration which leads to achieve the highest efficiency. Therefore, the influence of the dithizone concentration on the corrected absorbance was studied by using 100 μL of H2Dz dissolved in CCl4 at different concentrations in the Table 2 Tolerance limits of interfering species in bismuth(III) (1.0 mL−1) determination by the developed method. Interfering species +

+

+

+

−

−

−

SO2− 4 ,

Li , Na , K , Ag , Cl , F , NO3 , − CO2− 3 ,CN , tartrate Hg2+, Mn2+, Ca2+, Cu2+, Ni2+, Al3+ Mg2+, Fe3+, Co2+, Cr3+ Pb2+, Zn2+, Cd2+

Analytical performance

A

B

Linear range (μg·L−1) Correlation coefficient (R2) Molar absorptivity (ε) (L·mol−1.cm−1) The Sandell's sensitivity(μg·cm−2) Slope Limit of detection, LOD (μg·L−1) Limit of quantification, LOQ (μg·L−1)

3–100 0.991 4.44 × 105 0.002 1.884 1.43 4.78

3–100 0.993 1.078 × 106 0.0005 5.07 0.54 1.80

range of 0.23 × 10−6–0.8 × 10−4 mol·L−1. As shown in Fig. 5, the absorbance increased with increasing concentration of dithizone until reaching to its constant value at 1.5 × 10−6 mol·L−1 (1.5 μmol·L−1). Thus, 150 μL of H2Dz solution at concentration level of 1 × 10−4 mol·L−1 was used in the recommended procedure.

3.2.5. Effect of centrifugation parameters Centrifugation is usually employed to collect the droplets dispersed in the solution after shaking completely. Therefore, the speed and time of centrifugation have been investigated in the range of 2000 to 5000 rpm and 1–5 min, respectively. The droplets were completely collected and sedimented to the bottom of tube after using centrifugation with speed 3500 rpm for 2 min.

3.2.6. Effect of extraction time In DLLME, extraction time is defined as the time between the injection of extraction mixture and starting centrifugation. The effect of extraction time was investigated in the range of 30 s to 15 min with constant experimental conditions. The obtained results showed that the extraction is accomplished in a very short time after the formation of cloudy solution. This is due to the infinitely large surface area between extraction solvent and aqueous phase after the formation of cloudy solution, and therefore, the equilibrium state was achieved quickly. Thus, one minute was chosen as the optimum condition for the extraction time for the proposed method.

3.3. Interferences The selectivity of the developed method was examined in the presence of various cations and anions under the established conditions. The tolerance limits of the coexisting ions, defined as the largest amount of foreign ion that causes an error in the bismuth determination larger than ±5%, are given in Table 2. The 17 common ions did not interfere even when they are present in 100-fold excess over the bismuth. Only Pb2 +, Zn2 +, Cd2 + interfered seriously with bismuth determination. However, the interference of Zn2+ and Cd2+ were eliminated by adding few drops of KCN (0.1% m/v) and the interference of Mg2+, Fe3+ and Al3 + were eliminated by adding few drops of NaF (0.1% m/v). The tolerance of the interfering ions was improved after modification to an acceptable limit (98 ± 2%).

Table 4 The determination of bismuth in certified reference materials and De–Nol drug by the developed procedure.

Interfering to analyte ratio

Sample

Certified valuea

Found valueb

Recovery (%)

t-valuec

1000:1

SRM 3106 De–Nol drug

10.00 mg/g 120 mg each tablet

9.72 ± 0.3 mg/g 119 ± 1.3 mg for drug

97.2 99.1

1.86 1.54

200:1 50:1 10:1

a b c

Certified value as reported in certificate. Mean value ± standard deviation (n = 4) and 95% confidence limit. Tabulated t-value at 3° of freedom at 95% confidence level is 3.18.

H.M. Al-Saidi et al. / Journal of Molecular Liquids 212 (2015) 635–640 Table 5 Determination of bismuth in water and hair samples by the developed spectrophotometric (A) and ICP-MS (B) methods (mean ± standard deviation, n = 5). Sample

Bismuth added (μg·L−1)

Tap water

– 25 50 – 25 50 – 25 50 – 25 50

Bismuth found (μg·L−1)

Recovery (%)

A

B

A

B

ND 25.4 ± 1.1 48.7 ± 1.3 ND 25.7 ± 0.9 51.8 ± 1.9 ND 24.4 ± 1.2 48.3 ± 1.8 ND 25.5 ± 0.8 48.8 ± 1.5

ND 25.9 ± 1.4 49.2 ± 0.9 ND 25.3 ± 0.8 50.7 ± 0.8 1.3 ± 0.9 23.9 ± 1.5 49.4 ± 0.8 – 24.2 ± 1.1 51.1 ± 1.4

– 101.6 97.4 – 102.8 103.6 – 97.6 96.6 – 102 97.6

– 103.6 98.4 – 101.2 101.4 – 95.6 98.8

639

by the proposed procedure and the results are given in Table 4. The obtained results were validated by statistical treatment using Student's t-test. As can be seen in Table 4, the calculated t values were less than tabulated value at 95% confidence level confirming no significant difference between the results obtained and the certified values.

The analytical characteristics of the proposed procedure including dynamic linear range, limit of detection (LOD), and limit of quantification (LOQ) were calculated as reported in [27], and summarized in Table 3. By the comparison between the values of molar absorptivity (ε), Sandell's sensitivity index, LOD, and LOQ of DLLME-spectrophotometry and DLLME-β-correction spectrophotometry, we can conclude that the sensitivity of developed method have been improved dramatically after applying β-correction technique. Another advantage of βcorrection spectrophotometry was the improvement of the relative standard deviation and the relative error of the developed method where these values were 1.5% and 1.1% respectively with β-correction technique, while, the relative standard deviation and the relative error of DLLME-spectrophotometry were 2.4% and 7.0%, respectively. The regressions of the linear plots without and with the use of β-correction spectrophotometry are given by Eqs. (4) and (5), respectively:

3.5.2. Analysis of bismuth in water and biological samples The validation of the proposed method was carried out by analyzing bismuth content in water samples (tap water, drinking water and wastewater) and biological sample (hair) with the aid of the direct calibration plot and the standard addition method. The tested water samples were processed at the optimum experimental conditions of the developed procedure as mentioned in the experimental section. Moreover, different concentrations of the Bi3 + ions in the range of 3–100 μg·L− 1 were spiked onto the tested water and hair samples, and the bismuth content in each sample was then determined via the developed spectrophotometric (A) and IC-MS (B) methods. The results summarized in Table 5 revealed that, the percentage recoveries of both methods were in good agreement and always higher than 95% confirming the accuracy of developed procedure and its independence from matrix. Finally, the proposed method largely minimized toxic organic solvent consumption and greatly increased the sensitivity of bismuth estimation. A comparison of the analytical features of the proposed method with many previously published methods e.g. flame atomic absorption spectrometry (FAAS) with slotted quartz tube (SQT) [28], adsorptive stripping voltammetry [29], flow injection-potentiometric [30], spectrophotometric methods [31–34], Sol–gel Bi(III) sensor [35], fluorescence quenching [36] and cloud point extraction coupled with thermo spray flame furnace atomic absorption spectrometric [37] are given in Table 6. From the table, we can conclude that, simplicity of operation, sensitivity, use of a few sample volume, minimizing the volumes of toxic organic solvents, and low cost are some of advantages of the proposed method. Therefore, this procedure is economic and environmentally friendly due to low organic solvent consumption, and low instrumentation cost.


A ¼ 1:884 Cx þ 0:022 r2 ¼ 0:991

ð4Þ

4. Conclusion


Ac ¼ 5:070 Cx þ 0:008 r2 ¼ 0:993

ð5Þ

In the present work, we have developed a simple, sensitive and economic procedure for preconcentration and determination of bismuth employing DLLME combined with microvolume β-correction spectrophotometry. Parameters related to the efficiency of microextraction, such as pH, complexant concentration, the volume ratio of disperser solvent and extraction solvent were discussed and optimized in detail. The real absorbance was in proportion to bismuth concentration in the range of 3–100 μg·L−1 with a correlation coefficient (R) of 0.993. The limit of detection (LOD) and limit of quantitation (LOQ) were

Drinking water

Waste water

Human hair⁎

96.8 102.2

⁎ In aqueous solution.

3.4. Figure of merits

3.5. Analytical application 3.5.1. Analysis of bismuth in the standard reference material 3106 and De–Nol drug To test the accuracy of the method, standard reference material (SRM) 3106 and De–Nol drug were analyzed for bismuth determination

Table 6 Comparison of the proposed method with other reported methods for determination of bismuth. Analysis method

LOD (μg·L−1)

Linear range (μg·L−1)

Remarks

References

FAAS with SOTa Cathodic adsorptive stripping voltammetry flow injection-potentiometric micro extraction-spectrophotometry First-derivative spectrophotometry β-correction spectrophotometry Modified (AgNPs)b-spectrophotometric Sol–gel Bi(III) sensor Fluorescence determination CPE-(TS-FF-AAS)c DLLME-microvolume β-correction spectrophotometry

1.6 – 2500 300 50 200 2.1 70 50 8 0.54

– 5–50 4200–2.1 × 106 1000–60,000 500–2500 200–3200 83.6–1672 125–875 130–2090 20–1000 3–100

Low sensitive and expensive and required large volume of toxic materials Low sensitive and use of hanging mercury dropping electrode Low sensitivity, high LOD, expensive and used toxic organic material Low sensitivity Low sensitivity and used toxic organic material Less sensitivity Low sensitivity and required large volume of toxic materials Less sensitivity and expensive Low sensitivity and required large volume of toxic materials less sensitivity and used toxic organic material Sensitive, simple, low cost, selective and environmentally friendly

[28] [29] [30] [31] [32] [33] [34] [35] [36] [37] Present work

a b c

Flame atomic absorption spectrometry (FAAS) with slotted quartz tube (SQT). Modified silver nanoparticles. Cloud point extraction coupled with thermospray flame furnace atomic absorption spectrometry.

640

H.M. Al-Saidi et al. / Journal of Molecular Liquids 212 (2015) 635–640

0.54 μg·L−1 and 1.80 μg·L−1, respectively. Good recoveries of bismuth were obtained in the range of 96.3–103.6% in different real samples confirming the accuracy of developed procedure. References [1] N. Yang, H. Sun, Coord. Chem. Rev. 251 (2007) 2354–2366. [2] N. Yang, H. Sun, Bismuth: Environmental Pollution and Health Effects, Encyclopedia of Environmental Health, Elsevier, Burlington, UK, 2011 414–420. [3] P. Thirupathi, S.S. Kim, Tetrahedron 65 (2009) 5168–5173. [4] S. Moyano, R.G. Wuilloud, R.A. Olsina, J.A. Gasquez, L.D. Martinez, Talanta 54 (2001) 211–219. [5] R. Pamphlett, M. Stottenbery, J. Rungby, G. Danscher, Neurotoxicol. Teratol. 22 (2000) 559–563. [6] H. Ashkenani, M.A. Taher, Int. J. Environ. Anal. Chem. 93 (2013) 1132–1145. [7] A.S. Ribeiro, M.A.Z. Arruda, S. Cadrore, Spectrochim. Acta B 57 (2002) 2113–2120. [8] O. Acar, Z. Kilic, A.R. Turker, Anal. Chim. Acta 382 (1999) 329–338. [9] H. Guo, Y. Li, P. Xiao, N. He, Anal. Chim. Acta 534 (2005) 143–147. [10] H.Y. Yang, W.Y. Chen, I.W. Sun, Talanta 50 (1999) 977–984. [11] M. Grabarczyk, A. Koper, Environ. Monit. Assess. 185 (2013) 5515–5522. [12] B. Liu, F. Wu, X. Li, Z. Fu, Q. Deng, C. Mo, J. Zhu, Y. Zhu, H. Liao, Microchem. J. 97 (2011) 20–24. [13] D.D. Afonso, S. Baytak, Z. Arslan, J. Anal. At. Spectrom. 25 (2010) 726–729. [14] Y. Okamoto, T. Fujiwara, H. Notake, Appl. Spectrosc. 55 (2001) 514–516. [15] A.P. Argekar, A.K. Shetty, Analyst 120 (1995) 1819–1822. [16] D.T. Burns, C.D.P. Dangolle, Anal. Chim. Acta 337 (1997) 113–116. [17] D.T. Burns, M.D. Dunford, Anal. Chim. Acta 334 (1996) 209–213.

[18] M.A. Farajzadeh, D. Djozan, R.F. Bakhtiyari, Talanta 81 (2010) 1360–1367. [19] S.R. Yousefi, F. Shemirani, Anal. Chim. Acta 669 (2010) 25–31. [20] M. Rezaee, Y. Yamini, A. Khanchi, M. Faraji, A. Saleh, J. Hazard. Mater. 178 (2010) 766–770. [21] H.W. Geo, Talanta 42 (1995) 891–895. [22] H.W. Gao, P.F. Zhang, L. Wang, J. Anal. Chem. 55 (2000) 863–869. [23] A. Hamza, A.S. Bashammakh, A.A. Al-Sibaaia, H.M. Al-Saidi, M.S. El-Shahawi, J. Hazard. Mater. 178 (2010) 287–292. [24] A. Abbaspour, L. Baramakeh, Talanta 57 (2002) 807–812. [25] A. Hamza, A.S. Bashammakh, A.A. Al-Sibaai, H.M. Al-Saidi, M.S. El-Shahawi, Talanta 57 (2002) 807–812. [26] Z. Marczenko, M. Balcerzak, Separation, Preconcentration and Spectrophotometry in Inorganic Analysis, 10 rd edn Elsevier, 2000 113. [27] J.C. Miller, J.N. Miller, Statistics for Analytical Chemistry, 4th edn Ellis Horwood, New York, 1994. [28] E. Kilinc, S. Bakirdere, F. Aydin, O.Y. Ataman, Spectrochim. Acta B 73 (2012) 84–88. [29] R. Hajian, E. Shams, Anal. Chim. Acta 491 (2003) 63–69. [30] M.F.S. Teixeira, O. Fatibello-Filho, Int. J. Pharm. 221 (2001) 115–121. [31] K. Wrobel, K. Wrobel, E.M. Colunga Urbina, Microchim. Acta 135 (2000) 87–90. [32] G. Gumus, H. Filik, B. Demirata, Anal. Chim. Acta 547 (2005) 138–143. [33] A. Abbaspour, L. Baramakeh, Talanta 65 (2005) 692–699. [34] S. Mohammadi, G. Khayatian, Spectrochim. Acta A 148 (2015) 405–411. [35] P.C.A. Jeronimo, A.N. Araujo, M.C.B. Montenegro, D. Satinsky, P. Solich, Anal. Chim. Acta 504 (2004) 235–241. [36] M.A. Taher, M. Rahimi, H. Fazelirad, J. Lumin. 145 (2014) 976–980. [37] C. Zeng, L. Ji, C. Zhou, F. Zhang, M. Liu, Q. Xie, Microchem. J. 119 (2015) 1–5.