Muneera Alrasheedia,
Salah M. El-Bahyb,
Refat El-Sayedcd,
Khaled F. Debbabide and
Alaa S. Amin*c
aDepartment of Chemistry, College of Science, Qassim University, Buraidah, 51452, Saudi Arabia
bDepartment of Chemistry, Turabah University College, Taif University, Taif, Saudi Arabia
cChemistry Department, Faculty of Science, Benha University, Benha, Egypt. E-mail: asamin2005@hotmail.com
dDepartment of Chemistry, Univ. College in Al-Jamoum, Umm Al-Qura University, 21955 Makkah, Saudi Arabia
eDepartment of Chemistry, High Institute of Applied Science & Technology of Monastir, Monastir, Tunisia
First published on 7th April 2025
Although modern reported methods, such as AAS, ICP-AES, ICP-MS, have good sensitivity, the high cost of equipment, the need for sophisticated instruments, separation and preconcentration steps and experienced technicians along with lack of precise methods make them cumbersome. Solid phase extraction (SPE) emerges as an attractive technique that reduces solvent consumption, minimizes exposure, shortens extraction time, and lowers disposal costs. Herein, a pioneering methodology for the quantification of minute amounts of silver is introduced, using 2-nitro-6-(thiazol-2-yl-diazenyl)phenol (NTDP) as a complexing agent and Triton X-100 as a nonionic surfactant within a ternary surfactant system at a pH of 5.3. This novel extraction strategy demonstrated selective preconcentration. The enriched solution was subjected to spectrophotometric analysis for the quantification of the analyte. After refining extraction and complexation parameters, a remarkable 250-fold increase in the enrichment factor was attained, highlighting a sensitivity boost of 509 times compared with traditional extraction approaches relying solely on nonionic surfactants. The key parameters of molar absorptivity and Sandell sensitivity were determined to be 6.04 × 106 L mol−1 cm−1 and 0.0018 ng cm−2, respectively. The calibration plot was observed from 5.0–175 ng mL−1, whereas Ringbom optimum concentrations ranged from 15–160 ng mL−1. The detection and quantification limits were 1.63 and 4.95 ng mL−1, respectively. The relative standard deviation (RSD) of the complex was 2.27. The suggested method was efficiently utilized for assessing the Ag+ concentration in real samples, producing acceptable outcomes.
Silver, which is a non-essential component in the human body, can be deposited on the skin and mucous membranes following ingestion or prolonged topical use. This accumulation may result in a persistent blue-gray discoloration and, in extreme instances, may lead to sudden death.6 Hence, the determination of silver has become a pivotal process in environmental surveillance and for the prevention of health epidemics.
Moreover, silver holds significance as a valuable precious metal7 owing to its outstanding thermal and electrical conductivities. However, there are concerns related to the interaction of silver with vital nutrients, especially selenium, vitamins E and B12, and copper, emphasizing its potential harm.8 Consequently, precise and accurate measurement of silver in diverse matrices mandate an approach of heightened sensitivity.
Globally, substantial amounts of silver are annually discarded as waste by galvanizing or photographic facilities and via engineering, manufacturing, and medical processes.9 Considering the exceedingly low concentrations of numerous elements in environmental samples (including silver), the precise determination and separation of these elements require the utilization of preconcentration or trace enrichment techniques.10–12
In the contemporary era, various analytical techniques are available for the direct identification of silver in authentic samples, including spectrophotometry,13–17 flame atomic absorption spectrometry (FAAS),18 spectrofluorometry,19,20 inductively coupled plasma atomic emission spectrometry (ICP-AES),21 electrothermal atomic absorption spectrometry (ETAAS),22,23 graphite furnace atomic absorption spectrometry (GFAAS),24,25 and inductively coupled plasma mass spectrometry (ICP-MS).26,27 These different approaches have been created for evaluating silver levels in various environmental samples. However, prior to precisely measuring low concentrations of silver in complex sample analyses, it is crucial to execute separation and preconcentration steps.
Solid-phase extraction (SPE) emerges as an attractive technique that reduces solvent consumption, minimizes exposure, shortens extraction time, and lowers disposal costs.28–37 Cloud point methodology has been successfully utilized for the preconcentration and extraction of metal ions following the formation of sparingly water–soluble complexes. Spectrophotometric determination of various elements, including iron,28 vanadium,29 gold,30 nickel,31 uranium,32 cobalt,33 bismuth,34 boron,35 gallium,36 and palladium,37 has been accomplished following solid-phase extraction utilizing complexing agents.
Various methods encompassing electrochemical and spectrometric techniques have been suggested for the assessment of silver in diverse environmental samples.38–42 Nevertheless, except for spectrophotometry, these methods generally involve higher expenses and greater instrument complexity, restricting their broad application for routine analytical tasks. Directly detecting trace metal ions in specific samples via spectrophotometry proves challenging due to their low sensitivity. Consequently, preconcentration procedures are often necessary. Different techniques have been employed for the enrichment of silver(I) ions and their separation from potential interferences, including liquid–liquid extraction,43 cloud point extraction,44 solid-phase extraction,45–48 and dispersive liquid–liquid microextraction.49–51
Until now, nonionic surfactants have been predominantly utilized in cloud point extraction (CPE), although zwitterionic surfactants and combinations of nonionic and ionic surfactants have also found application.52,53 The occurrence of clouding is ascribed to the effective dehydration of the hydrophilic segment of micelles under elevated temperature conditions. Additionally, there have been indications of several substances causing phase separation in aqueous solutions of bile salts, such as sodium cholate (NaC), even at room temperature.54 Conversely, among cationic surfactants, cetyltrimethyl ammonium bromide (CTAB) undeniably serves as an example of a self-assembled ordered medium with micelles, along with other structures and phases. CTAB has been extensively utilized in analytical chemistry for various purposes.55–58
Our literature survey did not reveal any instances of the application of NTDP as a complexing agent for metal ions in SPE. The current study is mainly focused on the suitability of SPE combined with UV-vis spectrophotometry to determine Ag+ ions. The effects of various experimental factors on the complex formation, enrichment, and extraction processes were thoroughly examined. To assess the feasibility of the developed method, it was applied to the quantification of Ag+ in samples of water, medical radiology waste, blood, food, and urine.
Diverse solutions covering a pH spectrum from 2.75 to 10.63, including universal, phosphate, acetate, and thiel buffers, were created using the method outlined previously.59 Acetonitrile solvent and potassium iodide salt were sourced from Merck. The NTDP employed in this investigation was synthesized following the method detailed in a prior report.60 A specific quantity was dissolved in 100 mL of absolute ethanol (2.5 × 10−3 M). The resulting solution exhibited stability for a period exceeding one month.
A mixture weighing 10 g underwent a heating process for 3.0 hours in a silicon crucible on a heated plate. The resulting charred material was treated according to our previous research.64 The obtained material was then placed in a furnace and heated overnight at 650 °C. Once cooled, the remaining substance was mixed with 3.0 mL of 30% H2O2 and 10 mL of concentrated HNO3.
This was followed by an additional 2.0 hours furnace treatment at the same temperature to ensure the complete elimination of any remaining traces of organic compounds. The definitive residue encountered treatment with 3.0 mL of concentrated hydrochloric acid and 2.0–4.0 mL of 70% perchloric acid, and heated to vaporize the fumes, ensuring the conversion of all metals into their corresponding ions.65 The compact residue was dissolved in water, sieved, and adjusted to 25 mL in a volumetric flask, maintaining a pH of 5.3 through the introduction of diluted KOH. Blank digestions were also executed. In sequence, the previously delineated preconcentration methodology was implemented.
In an aqueous medium containing Triton X-100, Ag+ forms a complex with NTDP, displaying its peak absorbance at 608 nm. The addition of iodide ions induces turbidity in the solution, facilitating extraction via the solid phase extraction (SPE) technique. The ternary complex developed in the phase rich in surfactant displays a maximum absorbance at 623 nm [Fig. 1], as opposed to the absorbance of NTPD at 486 nm. Absorbance measurements were taken at 623 nm, with a reagent blank serving as the reference after separation of the surfactant-rich phase.
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Fig. 1 Absorption spectra for NTDP and its complex with 10 mg mL−1 Ag+ without SPE and 100 ng mL−1 Ag+ with SPE at optimum conditions. |
The impact of NTDP concentration on the preconcentration, determination, and extraction of Ag+ was investigated within the 0.5–15 × 10−5 M range, as illustrated in Fig. 2. The complex that was formed exhibited an increase with rising NTDP concentration up to 7.5 × 10−5 M, followed by a decline at higher concentrations. It was anticipated that an elevation in NTDP concentration would lead to an augmentation in the complex's absorbance. Nevertheless, for concentrations ≥ 9.0 × 10−5 M, a significant rise in the uncomplexed NTDP concentration was observed in the phase rich in surfactant. As a result, the reduction in absorbance change at concentrations ≥ 9.0 × 10−5 M is probably due to increased competition between unbound NTDP and the complexes during extraction into the surfactant-rich phase. The optimal NTDP concentration was identified as 7.5 × 10−5 M.
The influence of pH (2.75–10.63) on the generated hue was tested at a consistent concentration of the complex within the surfactant-rich phase. Various buffer solutions (universal, borate, acetate, phosphate, and thiel buffers) were employed. Optimal outcomes were observed with acetate buffers, displaying high conformity and stable results. The absorbance of the Ag+–NTDP-Triton X-100 system at 623 nm within the surfactant-rich phase was assessed in relation to the reagent blank. Within the 5.0–5.6 range, the absorbance remained relatively unchanged. Consequently, pH 5.3 was identified as the most suitable [Fig. 3]. To ascertain the optimal volume, the amount at pH 5.3 was assessed, and the peak absorbance value was achieved with the addition of 11–14 mL. Consequently, for all subsequent examinations, a volume of 12.5 mL of pH 5.3 per 100 mL was utilized.
The impact of 5.0% Triton X-100 concentration on the complexation of Ag+ was explored within the volume range of 0.5–5.0 mL. Absorbance demonstrated an increase with escalating Triton X-100 concentration, reaching a peak at 2.5 mL of 5.0%, followed by a decline at higher concentrations. Simultaneously, the absorbance of the blank also rose with an increasing concentration of Triton X-100. This phenomenon is attributed to the heightened extraction of NTDP due to the increased Triton X-100 concentration. However, the disparity between the sample and blank (ΔA) showed an escalation up to 2.5 mL of 5.0% Triton X-100 and diminished at higher concentrations (Fig. 4). Hence, 2.5 mL of 5.0% Triton X-100 was considered as the optimal concentration.
Conversely, progressively increasing the concentration of Triton X-100 leads to a gradual decline in the absorbance of the tested solution. This effect can be attributed to the expansion of the micellar phase, which in turn causes dilution after the surfactant dissolves in the organic solvent. Therefore, the Triton X-100 concentration was kept constant at 0.1% for all subsequent analyses to ensure consistency in sample preparation.
The introduction of salt has the potential to induce the separation of non-ionic surfactant solutions into immiscible surfactant-rich and surfactant-poor phases. A variety of inorganic salts underwent examination, including KBr, NaCl, KI, KNO3, and NaF, with KI emerging as the optimal choice. Consequently, iodide was incorporated to facilitate the extraction of the complex and stimulate the growth of micelle. The impact of iodide concentration was examined within the 0.005–0.08 M range. The introduction of 5.0 mL of 0.4 M iodide into the prepared 100 mL solution significantly enhanced the efficiency of complex extraction. However, an increase in iodide concentration led to a noticeable decline in absorbance. As a result, a final iodide concentration of 0.02 M within the 100 mL solution was determined to be optimal for subsequent experiments.
Another important factor that affected the complex formation yield was the heating temperature in the water bath. Determining the optimal incubation duration and equilibration temperature played a pivotal role in ensuring the culmination of the reaction and attaining maximum efficiency for seamless phase separation and Ag+ preconcentration. The influence of the temperature of equilibration on Ag+ extraction recovery was explored across the 20–70 °C spectrum. A discernible increase in extraction recovery was noted within the 35–45 °C range, stabilizing up to 50 °C. Consequently, 40 °C was singled out as the temperature for achieving peak absorbance. Subsequently, the experiment proceeded with a fixed equilibration temperature of 40 °C, and the impact of time of incubation on solid phase extraction (SPE) was scrutinized within the 1.0–15 min range. The results demonstrated that a 5.0 min incubation period was adequate for the separation process. Additionally, the time of centrifugation and cooling was also checked to complete the optimization process of the method for Ag+ determination. Centrifugation at 3800 rpm for 5.0 min was established as satisfactory for ensuring a successful SPE.
In relation to sensitivity, different solvents were explored to pinpoint the most appropriate one for achieving optimal outcomes, given the tendency of the surfactant-rich phase to precipitate. Between methanol, acetonitrile, ethanol, acetone, and DMF, acetonitrile produced the most advantageous results because of its elevated sensitivity and limited overlap of spectral elements. As a result, acetonitrile was selected to guarantee a suitable quantity of the specimen for transfer and absorbance measurements, along with an ideal preconcentration factor. A volume of 0.4 mL of acetonitrile was determined to be adequate for dissolving the precipitated ternary complex. Thus, the proposed procedure achieved a preconcentration factor of 250.
The absorbance of acetone-based solutions exhibited a continuous increase, likely due to solvent evaporation caused by its high volatility, leading to a rise in complex concentration within the container. In contrast, monoatomic alcohols caused the gradual degradation of the NTDP-Ag+ complex. Specifically, the ethanol solution became completely colorless after 12 hours, whereas the methanol solution lost its color within 2.0 hours. Meanwhile, the solution prepared in DMF remained stable over time; however, the blank sample also absorbed light at the selected wavelength, which was likely linked to the solvent's basic nature and the conversion of the ligand into its anionic form. Among the tested solvents, acetonitrile exhibited the lowest volatility, ensuring the highest stability of the complex over time. Furthermore, acetonitrile significantly reduced the viscosity of the surfactant-rich phase while maintaining minimal absorbance in the blank solution. Due to these advantages, acetonitrile was chosen for further experimentation.
Regarding the ternary compound with Triton X-100, the results indicated the creation of a 1:
1 complex between the [(NTDP)Ag] compound and Triton X-100. Consequently, the findings pointed to a stoichiometric balance of 1
:
1
:
1 [(NTDP)Ag][Triton X-100], as illustrated in the following equations. The computed conditional formation constant (log
K) utilizing the Harvey and Manning formula with data derived from the two previously mentioned techniques was established at 5.17, whereas the actual constant was 5.05.
Ion added | Tolerated, mg |
---|---|
K+, Na+, tartaric acid, acetate | 12.0 |
Li+, Al3+, N, P, Cl, S, oxalic acid | 10.0 |
Ca2+, Mg2+, S, Sr2+, Ba2+, Br− | 9.0 |
Ce4+, Mn2+, UO22+, W6+ | 7.5 |
F−, Cr6+, B3+, ClO3− | 6.0 |
Bi3+, Ti4+, V5+ | 5.0 |
Cr6+, Mo6+ | 3.8 |
Cd2+, Tl3+, Sn4+, Pd2+ | 3.2 |
Ru3+, Pb2+, Hg2+ | 2.75 |
Os8+, Zr4+ | |
Cr3+, La3+, Sb3+, Co2+, Ni2+ | 2.25 |
Se4+, Te4+, Au3+, Sn2+ | 1.5 |
Rh3+, Ir3+, Th4+, Ru3+ | 0.75 |
Pt4+, Cl−, Zn2 | 0.20 |
I−, CN−, SCN− | 0.08 |
Fe2+, Fe3+, Cu2+ | 0.02 |
The results suggest that increased concentrations of specific common anions and cations do not interfere with the determinations of the analyte, underscoring the satisfactory selectivity of the developed approach. However, Fe2+, Fe3+ and Cu2+ can cause interference in the assessment of Ag+, even at a ratio of 20:
1. To enhance the specificity of Ag+ detection in the presence of Fe2+, Fe3+, and Cu2+ ions, the potential use of masking agents—including sodium thiosulfate, potassium thiocyanate, ascorbic acid, o-phenanthroline, and thiourea—was investigated. The results indicated that a 200-fold excess of Fe2+ and Fe3+ did not interfere with Ag+ analysis when o-phenanthroline and thiocyanate were utilized as masking agents. Similarly, a 2.0% ascorbic acid solution effectively masked the presence of Cu2+ at the same concentration ratio. Additionally, EDTA, along with sodium salts of tartrate and thiosulfate, demonstrated the ability to suppress interference from various ions; however, they also contributed to a reduction in solution absorbance.
Parameters | After CPP | Before CPP |
---|---|---|
a Average of sex determination. | ||
Amount of acetonitrile | 0.4 | — |
pH | 5.3 | 5.3 |
Optimum [CPAHPD] (M) | 7.5 × 10−5 | 7.5 × 10−4 |
Reaction time (min) | 5.0 | 5.0 |
Stirring time (min) | 5.0 | — |
Beer's range (ng mL−1) | 5.0–175 | 500–15000 |
Ringbom range (ng mL−1) | 15–160 | 800–14400 |
Molar absorptivity (L mol−1 cm−1) | 6.04 × 106 | 1.19 × 103 |
Sandell sensitivity (ng cm−2) | 0.0018 | 9.09 |
Intercept | ||
Slope | 5.6 | 0.011 |
Intercept | −0.006 | 0.009 |
Correlation coefficient (r) | 0.9995 | 0.9980 |
RSDa (%) | 2.27 | 3.76 |
Detection limits (ng mL−1) | 1.63 | 175 |
Quantification limits (ng mL−1) | 4.95 | 515 |
Preconcentration factor | 250 | — |
Improvement factor | 509 | — |
The detection limit,66 computed as CL = 3SB/m (where CL, SB, and m denote the limit of detection, standard deviation of the blank, and slope of the calibration graph, respectively), was found to be 1.63 ng mL−1. When analyzing Ag+ in a 100 mL sample solution that undergoes preconcentration into a final volume of 0.4 mL acetonitrile, the concentration is amplified by a factor of 250. The enhancement factor was found to be 509, calculated as the ratio between the slope of the calibration curve obtained through the CPE technique and the slope of the calibration curve in micellar media without preconcentration.
The relative error and RSD were calculated for six repeated analyses of 100 ng mL−1 of Ag+, resulting in values of 2.43% and 2.14%, respectively. Similarly, for 150 ng mL−1 of Ag+, the RSD and relative error were found to be 2.54%, and 2.27%, respectively.
The attributes of the recommended method have been compared with those of alternative approaches. Table 3 and 4 contrast the analytical quality parameters of the proposed method with those previously reported for Ag+ determination. The comparison reveals that the recommended technique exemplifies analytical characteristics on par with previous studies focused on Ag+ determination. As a result, the combination of solid-phase extraction (SPE) with spectrophotometric detection stands out as a straightforward, sensitive, and selective approach for the determination and preconcentration of Ag+.
Reagent | Characteristicsa | Ref. |
---|---|---|
a Remarks: ε/L mol−1 cm−1; linear range μg mL−1. | ||
5-[p-Dimethylamino) benzylidene]rhodanine | Absorbance coefficient (ε): 3.5 × 104. Measurable range: 10–40. The reagent cost is high. Addition of poly(vinyl alcohol)-200 is necessary for enhanced ε, and color development takes 15 min. Restricted aqueous phase volume. Interference observed from a few metal ions | 67 |
4-(2-Hydroxy-4-substituted-azobenzene)-2-methylquinoline | Measurable range: 2.5–23.0. Restricted aqueous phase volume. Significant interference observed from certain metal ions. Primarily employed in photographic fixing solutions | 63 |
Dithizone | Absorbance coefficient (ε): 3.45 × 104. Measurable range: 0.1–6.0. Extraction into polyurethane and elution with Me2CO. Restricted aqueous phase volume. Interference observed from certain metal ions. Utilized in glass analysis | 68 |
Dithizone immobilized in a polymethacrylate matrix | Solid phase spectrophotometric determination of silver; with a detection limit of 0.01 μg L−1. The methodology was employed for the analysis of mineral waters and protargol medication | 69 |
5-[4-(2-Methyl-3-hydroxy-5-hydroxy-methyl)pyridylene] rhodanine | ε: 1.5 × 104. Linear range: 0.25–4.0. The reagent is costly. There is a constraint on the volume of the aqueous phase, and interference is observed from Au3+, Hg2+, I−, Pd2+, Br−, and S2O32−. The determination of silver was carried out in drug and ore samples | 70 |
2-Carboxybenzalaldehyde thiosemicarbazoneoctylmethyl-ammonium chloride | Linear range: 10–70. The method is time-consuming, and there is interference from common metal ions. It was applied to ore samples | 71 |
4,7-Dimethyl-2-thiol-2-thion-1,3,2-dioxophosphorinan (DOPh111) | Linear range: 1.0–18.0. The method includes replacing Cu2+ from Cu(DOPh111)2 with silver and measuring the decrease in the absorbance of the Cu(DOPh111)2 toluene solution. SCN−, F−, S2O32−, and Hg2+ seriously interfered. It was applied to some standard samples | 72 |
2-Nitroso-1-naphthol -4-sulfonic acid | ε: 6.47 × 103. Dynamic range: 0.2–30. Preconcentration factor: 80, sensitivity: 0.198 (d4A dλ4)/μg mL−1; detection limit: 0.15 μg mL−1. The method exhibits high selectivity for Ag+, and the utilization of derivative spectrophotometry significantly enhances both sensitivity and selectivity. Applied successfully to standard alloys and biological samples | 73 |
2-(8-Hydroxyquinolin -5-ylazo)benzoic acid | ε: 3.65 × 104. Dynamic range: 0.05–0.65. The reagent is costly. Separation of various metal ions as hydroxide is necessary due to interference. Applied to specific geological samples | 74 |
Bromopyrogallol red cetylpyridinium chloride | ε: 3.2 × 103. Linear range: 2.15–8.6. Limited aqueous volume, a few metal ions interfered. Applied to silver amalgam and dental prosthesis | 75 |
NTDP | ε: 6.04 × 106. Linear range: 5.0–175 ng mL−1. Limited aqueous volume, a few metal ions interfered. Applied to silver in environmental samples | This work |
Reagent | Medium/solvent | Interfering ions | λmax (nm) | ε (×104) L mol−1 cm−1 | Linear range (μg mL−1) | Ref. |
---|---|---|---|---|---|---|
Dithizonate | Extraction with Chloroform | Hg2+, Cd2+, Pb2+, CN−, I− | 565 | 5.5 | 0–1.0 | 75 |
2-(2-Quinolylazo)-5-diethylaminophenol | Aqueous (SDS), pH = 5.0 | I−, CN−, Pt4+, Br− | 590 | 13.3 | 0.01–0.6 | 76 |
2-Carboxybenzaldehyde thiosemicarbazone | Extraction with toluene | Hg2+, Cu2+, CN−, I− | 350 | 1.7 | 0.1–0.7 | 71 |
2-(3,5-Dibromo-2-pyridylazo)-5-diethylaminophenol | Aqueous (pH = 5), SDS | Zn2+, Co2+, Fe3+, Cu2+, Pb2+, Hg2+ | 565 | 6.4 | 0.02–0.48 | 77 |
1,10-Phenanthroline, tetrabromophenolphthalein ethyl ester | Extraction with 1,2-dichloroethane | I−, Sn4+, Hg2+, Co2+, Ni2+, Fe2+, Zn2+,Cd2+ | 610 | 36.5 | 0.0004–0.032 | 78 |
o-Carboxylbenzene diazoaminoazobenzene | Aqueous (pH = 11), OP | Fe3+, Cd2+, Ni2+ Cu2+, Zn2+ | 540 | 8.2 | 0–0.48 | 79 |
Sulfochlorophenolazothio-rhodanine | Aqueous pH = 2.8, Triton X-100 | Hg2+, Pd2+, Pt4+, Au3+ | 540 | 6.3 | 0–0.8 | 80 |
Thio-Michler's ketone | Aqueous (pH = 5), SDS | Au3+, Pd2+, Hg2+, Pt4+, Ir2+ | 535 | 9.4 | 0–0.4 | 81 |
Meloxicam | Aqueous pH 4.6 and Triton X-100 | Fe3+, Cd2+, Ni2+, Cu2+, Zn2+ | 412 | 1.1 | 1.0–15.0 | 82 |
2-(2-Quinolylazo)-5-diethylaminoaniline | Aqueous (pH = 6.5), SDS | 580 | 13.9 | 0.01–0.6 | 83 | |
NTDP-SPE | Aqueous pH = 5.3, Triton X-100 | Fe3+, Cu2+ | 623 | 604 | 0.005–0.175 | This work |
Sample | Added ng mL−1 | Founda (ng mL−1) | Recovery (%) | t-test | F-value | |
---|---|---|---|---|---|---|
Proposed | FAAS | |||||
a Mean of five extractions.b From a rinse water of photography.c From Sewa mineral water.d Not detected.e Collected at Zagazig city, Egypt (Dec. 2024).f From drinking water system of Beha, Egypt.g From Benha river water (Nile river).h Mediterranean sea water. | ||||||
Waste waterb | — | 63.0 ± 1.8 | 62.5 ± 1.6 | — | 1.32 | 2.71 |
10 | 72.4 ± 1.6 | 72.9 ± 1.7 | 99.18 | 1.19 | 2.39 | |
20 | 84.1 ± 1.4 | 83.3 ± 1.8 | 101.33 | 1.06 | 2.25 | |
Mineral waterc | — | NDd | — | |||
50 | 49.3 ± 0.24 | 65.7 ± 0.9 | 98.60 | 1.82 | 3.33 | |
100 | 100.8 ± 0.47 | 98.7 ± 0.8 | 100.80 | 1.17 | 2.36 | |
Rain watere | — | ND | — | |||
60 | 59.3 ± 0.22 | 60.8 ± 0.7 | 98.83 | 1.37 | 2.98 | |
120 | 121.7 ± 0.45 | 118.7 ± 1.0 | 101.42 | 1.25 | 2.81 | |
Tap waterf | — | ND | — | |||
75 | 76.2 ± 0.21 | 73.9 ± 0.9 | 101.60 | 1.87 | 3.26 | |
150 | 149.1 ± 0.43 | 151.6 ± 1.0 | 99.40 | 1.77 | 3.06 | |
River waterg | — | ND | — | |||
40 | 40.8 ± 0.23 | 39.0 ± 0.8 | 102.00 | 1.31 | 2.65 | |
80 | 78.8 ± 0.45 | 81.5 ± 0.9 | 98.50 | 1.13 | 2.39 | |
Sea waterh | — | ND | — | |||
70 | 69.2 ± 0.26 | 71.5 ± 1.1 | 98.86 | 0.96 | 2.18 | |
140 | 138.8 ± 0.48 | 141.7 ± 1.3 | 99.14 | 1.11 | 2.34 |
To gauge the reliability of the proposed technique, the procedure was employed to quantify trace amounts of Ag+ in various biological and food samples (Table 6). To confirm the precision of the established protocol, recovery experiments were conducted by adding different quantities of silver ions to the samples prior to any pre-processing. The outcomes are presented in Table 6, indicating recoveries ranging between 98.0% and 102.0% (±2.0% due to the interference of some diverse ions), affirming the precision of the suggested approach. The method was successfully employed for the determination of Ag+ ions in samples of radiological film and sulphadiazine cream (Table 7). The analysis of Ag+ in both samples was carried out using the cloud point precipitation with spectrophotometric analysis employing the standard additions method, as detailed in Table 3. The results were in good agreement with the data obtained from flame atomic absorption spectrometry (FAAS).
Sample | Added (ng mL−1) | Founda (μg mL−1) | Recovery (%) | |
---|---|---|---|---|
Proposed | FAAS | |||
a Mean ± SD (n = 6). | ||||
Human blood (ng mL−1) | — | 0.00 | 0.00 | — |
10 | 10.2 ± 0.20 | 9.7 ± 0.56 | 102.00 | |
20 | 19.7 ± 0.15 | 21.0 ± 0.43 | 98.50 | |
30 | 29.6 ± 0.33 | 31.2 ± 0.68 | 98.67 | |
Human urine (ng mL−1) | — | 0.00 | 0.161 | — |
20 | 19.6 ± 0.26 | 19.3 ± 0.71 | 98.00 | |
40 | 40.2 ± 0.55 | 39.2 ± 0.39 | 100.50 | |
60 | 59.4 ± 0.19 | 61.1 ± 0.46 | 99.00 | |
Green tea sample (ng g−1) | — | 0.00 | 0.00 | — |
25 | 25.1 ± 0.32 | 24.8 ± 0.55 | 100.40 | |
50 | 49.7 ± 0.41 | 51.6 ± 0.67 | 99.40 | |
75 | 76.2 ± 0.28 | 74.3 ± 0.74 | 101.60 | |
Rice (ng g−1) | — | — | ||
40 | 40.6 ± 0.51 | 41.0 ± 0.63 | 101.50 | |
80 | 79.6 ± 0.72 | 81.6 ± 0.63 | 99.50 | |
120 | 119.0 ± 0.31 | 122.2 ± 0.63 | 99.17 | |
Lentils (ng g−1) | — | — | ||
30 | 29.7 ± 0.32 | 30.7 ± 0.63 | 99.00 | |
60 | 59.1 ± 0.47 | 61.9 ± 0.63 | 98.50 | |
90 | 91.4 ± 0.52 | 88.8 ± 0.63 | 101.55 | |
Wheat (ng g−1) | — | — | ||
50 | 50.7 ± 0.55 | 49.1 ± 0.63 | 101.40 | |
100 | 101.2 ± 0.62 | 99.0 ± 0.63 | 101.20 | |
150 | 148.3 ± 0.76 | 152.2 ± 0.63 | 98.87 | |
Spices (ng g−1) | — | — | ||
45 | 44.7 ± 0.37 | 45.8 ± 0.63 | 99.33 | |
90 | 91.0 ± 0.51 | 89.0 ± 0.63 | 101.11 | |
135 | 133.8 ± 0.82 | 137.5 ± 0.63 | 99.11 | |
Corn (ng g−1) | — | — | ||
55 | 55.9 ± 0.56 | 54.0 ± 0.63 | 101.64 | |
110 | 111.5 ± 0.63 | 108.7 ± 0.63 | 101.36 | |
165 | 163.7 ± 0.87 | 167.5 ± 0.63 | 99.21 |
Sample | Added ng mL−1 | Founda (ng mL−1) | Recovery% | t-Testb | F-Valueb | |
---|---|---|---|---|---|---|
Proposed | FAAS | |||||
a Results average of six consecutive measurements.b Theoretical values for t and F at 95% confidence limit are 2.57 and 5.05, respectively. | ||||||
Silver sulphadiazine | 0.00 | 7.3 ± 0.35 | 7.6 ± 0.60 | — | 2.82 | 1.57 |
15.0 | 22.5 ± 0.25 | 22.2 ± 0.75 | 100.90 | 3.46 | 1.81 | |
30.0 | 37.1 ± 0.40 | 38.0 ± 0.95 | 99.46 | 2.94 | 1.63 | |
40.0 | 47.7 ± 0.50 | 47.3 ± 0.95 | 100.85 | 2.54 | 1.37 | |
Radiological film | 0.00 | 12.5 ± 0.55 | 12.7 ± 0.95 | — | 2.89 | 1.61 |
10.0 | 22.4 ± 0.35 | 23.0 ± 0.80 | 99.56 | 2.47 | 1.38 | |
20.0 | 32.6 ± 0.20 | 33.0 ± 0.76 | 100.31 | 3.26 | 1.71 | |
30.0 | 42.7 ± 0.25 | 42.6 ± 0.85 | 100.47 | 3.71 | 1.85 | |
Photographic plate | 0.00 | 45.5 ± 0.60 | 45.3 ± 1.30 | — | 2.57 | 1.41 |
20.0 | 66.4 ± 0.45 | 64.6 ± 1.10 | 101.37 | 3.62 | 1.82 | |
40.0 | 84.6 ± 0.30 | 87.1 ± 0.80 | 98.95 | 2.67 | 1.48 | |
60.0 | 106.8 ± 0.35 | 104.2 ± 0.95 | 101.23 | 3.51 | 1.78 |
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