Interferences In Determination Research Articles

Greener synthesis of novel nanocomposite material for efficient and selective trace detection of Pb<sup>2+</sup>: Insights of stability and real implications of fabricated electrode

This work reports the use of highly efficient nanocomposite material fabricated glassy carbon electrode (Ag(NPs)/ChS/GC) in the trace detection of Pb<sup>2+</sup> using differential pulse voltammetry (DPV). A facile method yielded the silane-grafted chitosan (ChS) using 3-trimethoxyoctylsilane, and the bioderived Ag(NPs) was <i>in situ</i> decorated on the ChS composite to obtain Ag(NPs)/ChS. X-ray Diffraction (XRD) results showed the presence of Ag(NPs) within the composite material. Spherical-shaped and uniform distribution of Ag(NPs) were observed in SEM and TEM images of the nanocomposite solid. The cyclic voltammetric studies revealed a significant increase in redox peak currents (i.e., 0.1283 mA), which was obtained using the Ag(NP)/ChS/GC compared to the bare glassy carbon electrode. Further, the electrochemical determination of Pb<sup>2+</sup> showed good linearity in anodic peak current and Pb<sup>2+</sup> concentrations (5.0-80.0 <i>μ</i>g/L), and the limit of detection was 1.97 <i>μ</i>g/L. With 10-fold increase in several cationic and anionic interfering ions, oxalic acid and glycine only show interference in determination of Pb<sup>2+</sup>. The reproducibility study showed a %RSD of 2.43%, and the electrode could be efficiently used for prolonged and repetitive detection having reasonably low %RSD of 2.55%. The real water analysis showed almost 100% recovery of Pb<sup>2+</sup> in two different real water samples.

Controlling organic interference in determination of soil mineral nitrogen

AbstractInorganic nitrogen (N) in the form of exchangeable ammonium (NH4+), nitrate (NO3−), or nitrite (NO2−) is normally extracted by shaking soil with a neutral salt solution and is subject to interference by soluble organic N (SON). After optimizing sequential diffusion methods to expedite recovery of NH4+–N and (NO3− + NO2−)‐N, 15N‐tracer studies were conducted to ascertain whether extraction is quantitative when performed on soils amended with 2 g 15N kg−1 using 0.2, 1, and 2 M potassium chloride (KCl) and can be carried out by a simple leaching method instead of conventional shaking‐filtration. The results verified a significant decrease in SON interference with the optimized diffusion procedures and showed that (a) interference is more serious for NH4+–N than for (NO3− + NO2−)‐N, (b) 2 M KCl is required for quantitative recovery of 15NH4+–N, and (c) leaching virtually eliminates organic interference during diffusion of (NO3− + NO2−)‐N. The leaching‐diffusion approach minimizes the inflating effect of SON on soil inorganic N analyses and will be especially useful in N isotope studies.

Indirect Determination of Amikacin by Gold Nanoparticles as Redox Probe.

Amikacin is an aminoglycoside antibiotic used for many gram-negative bacterial infections like infections in the urinary tract, infections in brain, lungs and abdomen. Electrochemical determination of amikacin is a challenge in electroanalysis because it shows no voltammetric peak at the surface of bare electrodes. In this approach, a very simple and easy method for indirect voltammetric determination of amikacin presented in real samples. Gold nanoparticles were electrodeposited at the surface of glassy carbon electrode in constant potential. The effect of several parameters such as time and potential of deposition, pH and scan rates on signal were studied. The cathodic peak current of Au3+ decreased with increasing amikacin concentration. Quantitative analysis of amikacin was performed using differential pulse voltammetry by following cathodic peak current of gold ions. Two dynamic linear ranges of 1.0 × 10-8-1.0 × 10-7 M and 5.0 × 10-7-1.0 × 10-3 M were obtained and limit of detection was estimated 3.0× 10-9 M. The method was successfully determined amikacin in pharmaceutical preparation and human serum. The effect of several interference in determination of amikacin was also studied.

Microwave-assisted wet digestion with H2O2 at high temperature and pressure using single reaction chamber for elemental determination in milk powder by ICP-OES and ICP-MS

In this work a green digestion method which only used H2O2 as an oxidant and high temperature and pressure in the single reaction chamber system (SRC-UltraWave™) was applied for subsequent elemental determination by inductively coupled plasma-based techniques. Milk powder was chosen to demonstrate the feasibility and advantages of the proposed method. Samples masses up to 500mg were efficiently digested, and the determination of Ca, Fe, K, Mg and Na was performed by inductively coupled plasma optical emission spectrometry (ICP-OES), while trace elements (B, Ba, Cd, Cu, Mn, Mo, Pb, Sr and Zn) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Residual carbon (RC) lower than 918mgL−1 of C was obtained for digests which contributed to minimizing interferences in determination by ICP-OES and ICP-MS. Accuracy was evaluated using certified reference materials NIST 1549 (non-fat milk powder certified reference material) and NIST 8435 (whole milk powder reference material). The results obtained by the proposed method were in agreement with the certified reference values (t-test, 95% confidence level). In addition, no significant difference was observed between results obtained by the proposed method and conventional wet digestion using concentrated HNO3. As digestion was performed without using any kind of acid, the characteristics of final digests were in agreement with green chemistry principles when compared to digests obtained using conventional wet digestion method with concentrated HNO3. Additionally, H2O2 digests were more suitable for subsequent analysis by ICP-based techniques due to of water being the main product of organic matrix oxidation. The proposed method was suitable for quality control of major components and trace elements present in milk powder in consonance with green sample preparation.

Plasma-based determination of inorganic contaminants in waste of electric and electronic equipment after microwave-induced combustion

A systematic study was performed for the determination of inorganic contaminants in polymeric waste from electrical and electronic equipment (EEE) for achieving an efficient digestion to minimize interferences in determination using plasma-based techniques. The determination of As, Br, Cd, Co, Cr, Cu, Ni, Pb, Sb, and Zn by inductively coupled plasma mass spectrometry (ICP-MS) and also by inductively coupled plasma optical emission spectrometry (ICP OES) was carried out after digestion using microwave-induced combustion (MIC). Arsenic and Hg were determined by flow-injection chemical vapor generation inductively coupled plasma mass spectrometry (FI-CVG-ICP-MS). Dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) with ammonia was also used for Cr determination. The suitability of MIC for digestion of sample masses up to 400mg was demonstrated using microcrystalline cellulose as aid for combustion of polymers from waste of EEEs that usually contain flame retardants that impair the combustion. The composition and concentration of acid solutions (HNO3 or HNO3 plus HCl) were evaluated for metals and metalloids and NH4OH solutions were investigated for Br absorption. Accuracy was evaluated by comparison of results with those obtained using high pressure microwave-assisted wet digestion (HP-MAWD) and also by the analysis of certified reference material (CRM) of polymer (EC680k—low-density polyethylene). Bromine determination was only feasible using digestion by MIC once losses were observed when HP-MAWD was used. Lower limits of detection were obtained for all analytes using MIC (from 0.005μgg−1 for Co by ICP-MS up to 3.120μgg−1 for Sb by ICP OES) in comparison to HP-MAWD due to the higher sample mass that can be digested (400mg) and the use of diluted absorbing solutions. The combination of HNO3 and HCl for digestion showed to be crucial for quantitative recovery of some elements, as Cr and Sb. In addition, suitable agreement of Cr to CRM value was only obtained by mixing NH4Cl to samples before combustion. No statistical difference (95% confidence level) was observed between the results obtained for As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn by MIC and HP-MAWD methods. Agreement with certified values was better than 96% using MIC for all inorganic contaminants. Particularly for Br, MIC was the method of choice for digestion due to the possibility of using diluted alkaline solutions for analyte absorption. Based on the obtained results, MIC can be considered as a suitable method for digestion of polymers from waste of EEEs for further plasma based determination of inorganic contaminants.

Ethamsylate (Dicynone) interference in determination of serum creatinine, uric acid, triglycerides, and cholesterol in assays involving the Trinder reaction; in vivo and in vitro.

The aim of our research was the quantification of interfering properties of the haemostatic drug Dicynone (ethamsylate) in serum creatinine, uric acid, cholesterol, and triglyceride assays using the Trinder reaction. Blood from patients was collected before and 15 minutes after administration of 500 mg Dicynone dose i.v. and the above mentioned analytes were quantified using Roche assays (Cobas 8000). In our in vitro experiment, we measured concentrations of the analytes in pooled serum aliquots with final concentrations of Dicynone additions 0, 30, 60, 150, and 300 mg/L. Aliquots with 60 mg/L Dicynone were also measured at 2, 6, and 8 hours after initial measurement when stored in 22 degrees C and 4 degrees C for comparison. Concentrations of the measured analytes in samples from patients administered with a 500 mg dose of Dicynone were lower in all cases (n = 10) when compared to values in samples taken immediately before treatment. The in vitro samples showed that considerable negative interference occurred even with the low concentrations of Dicynone additions (30 and 60 mg/L), showing the strongest negative interference in creatinine values, followed by uric acid, triglycerides, and cholesterol. Using in vitro samples, we showed strong time and temperature dependence on Dicynone interference. We found and proved significant negative interference of the drug Dicynone (ethamsylate) in the clinical analysis of blood using in vivo and in vitro experiments. Furthermore, we observed a change of this effect in serum matrix over time and at different storage temperatures.

Nickel/Copper nanoparticles modified TiO2 nanotubes for non-enzymatic glucose biosensors

Highly ordered TiO2 nanotube arrays (TiO2NTs) evenly modified by Ni–Cu nanoparticles were successfully prepared by potential step method. Their morphologies, structures, and alloy composition were characterized by FESEM, XRD and EDS, respectively. The as-prepared Ni–Cu/TiO2NTs electrodes were employed for non-enzymatic glucose detection in alkaline electrolyte and showed better electro-catalytic activity compared with Ni/TiO2NTs and Cu/TiO2NTs electrodes. Factors that affected the electrocatalysis of the electrodes were examined and optimized. Consequently, a sensitive amperometric electrode of glucose was achieved under 0.6V vs. Ag/AgCl with a high sensitivity (1590.9μAmM−1cm−2), low detection limit (5μM) and wide linear range from 10μM to 3.2mM (R2=0.993). Furthermore, the oxidable species such as ascorbic acid and uric acid showed no significant interference in determination of glucose. The experiment results revealed a very good reproducibility and high stability for the proposed Ni–Cu/TiO2NTs electrodes.

Preparation of Pulse Deposited Pt/Ni Nanowires Electrode for Glucose Detection in Alkaline Solution

The development of an amperometric non-enzymatic electrode based on alloyed Pt/Ni nanowire arrays (NWAs) was described. The effect of pulse time on the fabrication of uniform nanowires was investigated by Scanning Electron Microscopy (SEM). In this regard, the pulse time had been designed in a way that the diffusion controlled deposition of metallic ions inside the pores had enough time to take place and uniform structure of nanowires was created. The resulting Pt/Ni NWAs electrode displayed good electro-catalytic activity for oxidation of glucose in alkaline solution. The impact of combination of Pt and Ni in a nanowire arrays electrode in comparison to individual Pt or Ni as nanowires has been studied by cyclic voltammetry in a wide range of potential scan. The amperometric response characteristics to glucose in 0.1 M NaOH solution were reported as low overpotential of 0.45 V vs. SCE, amperometric response time of almost 3 s, linear concentration range extended from 2 to 8 mM (R = 0.997), with 1.5 µM detection limit. Furthermore, the oxidable species such as ascorbic acid and uric acid showed no significant interference in determination of glucose.

Template-based electrodeposition of Pt/Ni nanowires and its catalytic activity towards glucose oxidation

An electro-catalysis non-enzymatic electrode is proposed based on alloyed Pt/Ni nanowire arrays (NWAs) for the detection of glucose. The Pt/Ni NWAs were prepared by pulse electrodeposition of Pt and Ni within a nano-pore polycarbonate (PC) membrane followed by a chemical etching of the membrane. The electrode structure is characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resulting Pt/Ni NWAs electrode shows high electrocatalytic activities towards the oxidation of glucose in alkaline solution. Consequently, a sensitive amperometric detection of glucose is achieved under 0.45 V vs. SCE with a low detection limit of 1.5 μM within a wide linear range from 2 μM to 2 mM ( R = 0.997). Furthermore, the oxidable species such as ascorbic acid and uric acid show no significant interference in determination of glucose. Finally, the experiment results reveal a very good reproducibility and high stability for the proposed Pt/Ni NWAs electrode.

IgM interference in determination of antiphospholipid antibodies and erythrocyte sedimentation rate in persistent polyclonal B-cell lymphocytosis with binucleated lymphocytes

IgM interference in determination of antiphospholipid antibodies and erythrocyte sedimentation rate in persistent polyclonal B-cell lymphocytosis with binucleated lymphocytes

Elimination of interferences in determination of platinum and palladium in environmental samples by inductively coupled plasma mass spectrometry

Various approaches were evaluated in order to eliminate the spectral interferences noted when Pt and Pd has to be determined in environmental dust samples by ICP-MS. The chemical separation of Pt and Pd from the matrix components on ion-exchange resins was applied. The performance of cation-exchange resins (Dowex 50 WX-8, Dowex 50 WX-2, Dowex HCR-S, Varion KS, Cellex-P) for the separation of interfering ions was then examined. It was found that Dowex 50 WX-8 shows best performance. The effects of mass, mesh number of resin and concentration of Cl − ions on matrix separation were also studied. Another approach was to use the anion-exchange sorbent Cellex-T, which allows almost total retention of both analytes followed by their elution with 0.1 mol L −1 thiourea in 1 mol L −1 HCl. This procedure however can be used only for platinum determination by ICP-MS. The accuracy of proposed procedures was confirmed by the analysis of certified material BCR-723, and then it was used for determination Pt and Pd in samples of road dust.

Mathematical Correction for Polyatomic Isobaric Spectral Interferences in Determination of Lanthanides by Inductively Coupled Plasma Mass Spectrometry

The determination of lanthanides by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is complicated by several spectral overlaps from M+, MO+ or MOH+ ions formed in the ICP. Especially, it is essential to avoid the spectral interferences from lighter lanthanide and Ba polyatomic ions on middle or heavier lanthanides. To tackle this problem, we have developed a mathematical correction method, which reduces all the spectral overlaps from oxide species of Pr, Nd, Ce and Sm over Gd, Tb, Dy and Ho, and Gd, Tb over Yb and Lu. It can also successfully correct the oxide and hydroxide interference of Ba over Eu. The effectiveness of the proposed the mathematical correction scheme is demonstrated for the USGS Standard Rock samples AGV-1 and G-2. The results show that the experimental data obtained by applying the mathematical correction scheme for lanthanides is in good agreement with the reported values, using pneumatic and ultrasonic nebulisation methods, for their ICP-MS analysis.

Rapid determination of total mercury in treated waste water by cold vapor atomic absorption spectrometry in alkaline medium with sodium hypochlorite solution

Addition of a sodium hypochlorite solution (9.2% (w/v)) was effective to reduce a sulfide interference in determination of organic mercury, including methylmercury and phenylmercury, as well as a previously reported determination of inorganic mercury by cold vapor atomic absorption spectrometry (CVAAS) in an alkaline medium. Total mercury ranging from 0.17 to 33 μg L −1 in 15 mL of sample solutions containing up to 200 mg L −1 of sulfide can be determined without any serious interference by sulfide when 1 mL of the sodium hypochlorite solution was added after dilution of the sample solution to 25 mL. The proposed method was simple and rapid because no digestion processes were required for the determination of total mercury; the time required for the determination was only about 5 min. The proposed method was applicable to the analysis of treated waste water.

A clean and rapid liquid chromatographic technique for sulfamethazine monitoring in pork tissues without using organic solvents.

A rapid method for the isolation and high-performance liquid chromatographic (HPLC) determination of sulfamethazine (SMZ) in pork tissues (kidney, liver, and muscle) without using organic solvents is developed. The isolation is performed by homogenization with an acid solution using an ultrasonic-homogenizer, followed by centrifugation. The HPLC analyses are performed using a reversed-phase C(4) column (150- x 4.6-mm i.d.), a mobile phase of 0.02 mol/L citric acid solution, and a photodiode array detector. The resulting HPLC chromatograms are free from interferences for determination and identification. The proposed technique is shown to be linear (r > 0.99) over the concentration range 0.1-2.0 microg/g for all pork tissues. Average recoveries of SMZ (spiked 0.1-2.0 microg/g) range from 87.6% to 90.2%, with inter- and intra-assay variabilities of less than 4%. The total time required for the analysis of one sample and limit of quantitation is less than 20 min and 0.09 microg/g, respectively.

One-step SFE-plus-C 18 selective extraction of low-polarity compounds, with lipid removal, from smoked fish and bovine milk

Co-extraction of lipid materials is the major source of interference in determinations of low-polarity compounds in many biological matrixes. "SFE-plus-C(18)", a recently developed supercritical fluid extraction method employing C(18) adsorbent in the extraction chamber, can enable selective extraction of low-polarity compounds in lipid-rich biological matrixes without a cleanup step. This study reports the application of the SFE-plus-C(18) method to the quantification of: 1. polycyclic aromatic hydrocarbons (PAH) in commercially purchased smoked fish; and 2. anti-cancer agents cyclophosphamide (CP) and suberoylanilide hydroxamic acid (SAHA) spiked into homogenized whole bovine milk. Over the course of SFE-plus-C(18)extraction, indigenous lipids are preferentially retained on the C(18) adsorbent. Compared with the conventional method, only 8-15% of the lipids in the smoked fish sample, and only 6-18% of the lipids in the milk sample, were co-extracted by SFE-plus-C(18). This reduction in the quantity of background lipids significantly improved chromatographic separations, retarded deterioration of the column, and dramatically improved the ability to quantify PAH present at trace levels in smoked fish by GC-MS. Using the SFE-plus-C(18) method, ten targeted PAH were detected in the range 9.5-13.5 ng g(-1) in the smoked fish sample. Compared with these levels, PAH extractions by use of conventional SFE gave values that were lower by 38-86%. Recoveries of CP and SAHA spiked into milk were close to 100% in both SFE-plus-C(18)and conventional SFE, where the lipid background during the chromatographic elution of CP and SAHA was not so severe.

Study of chemical and spectral interferences in the simultaneous determination of As, Bi, Sb, Se and Sn by hydride generation inductively coupled plasma atomic emission spectrometry

Chemical and spectral interferences from Cd(II), Co(II), Cu(II), Fe(III) and Ni(II) in the simultaneous determination of As, Bi, Sb, Se and Sn by continuous flow hydride generation inductively coupled plasma atomic emission spectrometry were investigated. The effect of the interfering metal concentration, in the range from 10 to 1000 μg ml −1, on the analyte intensity signals was evaluated. Various reagents used for elimination of chemical interferences, i.e. EDTA, thiourea, KCN and KI were employed and their effectiveness in the reduction of chemical interferences in the determination of five hydride-forming elements was compared and discussed. In addition, the precipitation of Cd, Co, Cu and Ni hydroxides using NaOH was used and found to be an efficient method of complete elimination of the transition metal interferences in the As and Se determination. Spectral interferences of analyte lines with lines of matrix metals (As–Cd and Sb–Co) transported into the plasma during hydride generation in the system with gas–liquid phase separation were observed for the first time and noticed to be significant.

Effect of Hemoglobin Variants (Hb J, Hb G, and Hb E) on HbA1c Values as Measured by Cation-Exchange HPLC (Diamat)

Hemoglobin A1c (HbA1c) is used for the long-term management of patients with diabetes mellitus (DM) (1)(2). Hb variants other than HbA1c and e-N-lysine-glycated Hb A may cause analytical interference in determinations of HbA1c (3)(4)(5)(6). In one study, the authors estimated the prevalence of thalassemia in Taiwan as 7%; moreover, ∼1% of the people in northern Taiwan are β-thalassemia heterozygotes (7). The occurrence of 24 abnormal Hbs (13 α-chain variants and 11 β-chain variants), including Hb G-Taipei, in populations in the Silk Road area of Northwestern China has been presented in a review (8). The frequency of thalassemia has been estimated to be ∼1 in 2350 in Japan (9) and even higher in North Africa (10). Hb E is the second most prevalent Hb variant worldwide and the third most prevalent variant in the US, after Hb S and C. Hb E is found primarily in Southeast Asia, especially among the Thai population (11). In the northeastern region of India, the gene frequency of Hb E is 10.9% (12). In a study of 222 000 blood samples in Canada, 23 cases of Hb J were identified (13). Given that the majority of hemoglobinopathic cases are from families of Asian, Southeast …

All-solid-state calcium-selective electrode prepared of soluble electrically conducting polyaniline and di(2-ethylhexyl)phosphate with tetraoctylammonium chloride as cationic additive

A novel all-solid-state Ca 2+-selective electrode was prepared of soluble electrically conducting polyaniline (PANI), di(2-ethylhexyl)phosphate (H +DEHP −) and tetraoctyl ammonium chloride (TOA +Cl −). PANI is made soluble and electrically conducting in tetrahydrofuran (THF) with H +DEHP −. The DEHP − anion is a complexing agent of the charged carrier type for Ca 2+. TOA +Cl − is added to this solution and electrode membranes are then prepared by drop casting on a GC substrate. PANI membranes containing 0–40% (m/m) TOA +Cl − has been studied in this work. The Ca 2+-sensitivity was significantly improved by incorporation of 20–30% (m/m) TOA +Cl − in the PANI electrode membrane. The best Ca 2+-sensitivity, 27.0 ± 0.4 mV/log a Ca (10 −1–10 −3 M CaCl 2, n = 3, LOD = 10 −4 M) in 0.1 M NaCl, was obtained with an electrode membrane containing 25% TOA +Cl − (PANI25). The reproducibility of the standard potential of three identical PANI25 electrodes was also very good. The selectivity coefficient (log K Ca, j pot) of this electrode towards j = Na +, K + and Li + is −1.6. However, Mg 2+ shows severe interference in determination of Ca 2+. No redox sensitivity was observed for the PANI25 electrode in a 10 mM Fe(CN) 6 3−/4− solution with 0.1 M CaCl 2 as the ionic background and only a weak redox response, 5 mV/decade, could be detected with 10 −3 M CaCl 2 as the ionic background. The pH sensitivity of the PANI25 electrodes studied was found to be approximately 5 mV/pH within the pH range of 4.5–9.7. Furthermore, the impedance spectrum and the cyclic voltammogram of the PANI25 electrode reveal that TOA +Cl − improves the ionic mobility within the PANI membrane. Finally, it is shown that the working mechanism of the PANI electrode membrane can be explained with the charge carrier model, which is usually applied to PVC-based ion-selective electrodes.

Study of interference in the flame atomic absorption spectrometric determination of lithium by using factorial design

The severe interference of a number of metallic ions found in brines, marine sediments and sea water in the determination of lithium is demonstrated. Calcium, iron and sodium significantly depressed the absorption signal on lithium in an air/acetylene flame. Aluminium, magnesium and strontium up to 1500, 1000 and 200 μg/mL, respectively, showed no interference in the determination of lithium under the same conditions. Potassium produced some suppression of the lithium signal at levels in excess of 1500 μg/mL. Experimental data were examined using the factorial design method. Interference was demonstrated in two synthetic samples (models of “brine” and “marine sediments” ) and natural marine sediment. It was possible to eliminate all interferences using a higher temperature (nitrous oxide/acetylene flame). In addition, by using the standard addition method the interference disappeared, which confirmed the interference as a proportional systematic error.

Identification of Chemical Interferences in Aldehyde and Ketone Determination Using Dual-Wavelength Detection

A method for the rapid and convenient identification of chemical interferences in the determination of aldehydes and ketones in air samples using the 2,4-dinitrophenylhydrazine (DNPH) method is described. The ratio of absorptions at 360 and 300 nm is characteristic for groups of related aldehydes and ketones as well as for the main interferents. It has been determined by UV/visible spectroscopy of pure standard compounds and confirmed by HPLC analysis with UV/visible detection of complex hydrazone mixtures. The application of this method has led to the identification of 2,4-dinitrochlorobenzene as another interfering compound after sampling of air with high nitrogen dioxide content when using hydrochloric acid as catalyst. The possibilities and limitations of the dual-wavelength detection with the DNPH method are discussed for mixtures of standards and real samples from car exhaust.