Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.2.004
M. Shachneva, N. Koryagina, E. Savelieva
A rapid, unified, highly sensitive and selective procedure for bis(2-chloroethyl)sulfide (sulfur mustard, SM) determination in matrices with high sorption activity using gas chromatography-tandem mass-spectrometry (GC-MS/MS) was developed. Ceramic tile, concrete, various types of bricks and polymers were studied as objects of the analysis. The parameters for the GC-MS/MS determination of SM were optimized. The efficiency of five solvents (diethyl ether, 2-chloropropane, acetonitrile, hexane, and acetone) for the extraction of SM from the various matrices was studied. 2-chloropropane was the extraction solvent of choice. The developed procedure is based on the extraction of SM from the matrix and the concentration of the extract under the stream of nitrogen to 0.2 mL followed by GC-MS/MS analysis. The LODs for SM in all investigated matrices were 0.7-0.9 ng/g (0.007-0.009 MPC). The long-term stability of SM in various materials was studied. It was shown that in brick, concrete and ceramic samples the residual amount of SM after five months of storage at 4°C was below the LOD of the method, while in polymer samples under the same storage condition the amount of SM has not changed significantly. The developed procedure has been applied to the analysis of samples from the former chemical weapons destruction facility.
{"title":"Improvement of the procedure for bis(2-chloroethyl)sulfide determination in matrices with high sorption activity","authors":"M. Shachneva, N. Koryagina, E. Savelieva","doi":"10.15826/analitika.2021.25.2.004","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.2.004","url":null,"abstract":"A rapid, unified, highly sensitive and selective procedure for bis(2-chloroethyl)sulfide (sulfur mustard, SM) determination in matrices with high sorption activity using gas chromatography-tandem mass-spectrometry (GC-MS/MS) was developed. Ceramic tile, concrete, various types of bricks and polymers were studied as objects of the analysis. The parameters for the GC-MS/MS determination of SM were optimized. The efficiency of five solvents (diethyl ether, 2-chloropropane, acetonitrile, hexane, and acetone) for the extraction of SM from the various matrices was studied. 2-chloropropane was the extraction solvent of choice. The developed procedure is based on the extraction of SM from the matrix and the concentration of the extract under the stream of nitrogen to 0.2 mL followed by GC-MS/MS analysis. The LODs for SM in all investigated matrices were 0.7-0.9 ng/g (0.007-0.009 MPC). The long-term stability of SM in various materials was studied. It was shown that in brick, concrete and ceramic samples the residual amount of SM after five months of storage at 4°C was below the LOD of the method, while in polymer samples under the same storage condition the amount of SM has not changed significantly. The developed procedure has been applied to the analysis of samples from the former chemical weapons destruction facility.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.3.003
M. I. Tivileva, V. M. Gruznov, M. Baldin, A. V. Kikhtenko, I. Naumenko
The results of the measurements of 2,4,6-trinitrotoluene (TNT) vapor concentration over its trace amounts, called thin films, on the glass surface with a concentration of 100 ng/cm2 in a square area with a side of 1 cm over time are presented. The trace amounts of TNT on the glass were formed by applying a solution of TNT in the acetonitrile diluted with the chemically pure acetone, followed by the evaporation of the solvents. In order to measure the TNT vapor concentration, an EKHO-V-IDTS portable multibacillary gas-chromatograph with preliminary TNT vapor concentration was used. A sampling of the TNT vapor above the object was carried out with a remote vortex sampler. The vapor sample was taken from a distance of 2 cm from the glass surface. The concentration in the mode of the complete capture of TNT vapors was carried out to the stainless-steel wire mesh. The vapor concentration was determined from the chromatographic peak amplitude. It was found that the concentration of vapor over the examined surface with an area of 1 cm2 decreases from 10-13 to 10-14 g/cm3 within 2.6 ± 0.3 hours. TNT vapor concentration value of 10-14 g/cm3 corresponds to the threshold concentration of TNT vapor for the modern detectors. Based on the assumption that the vapor concentration is proportional to the amount of the TNT mass on the surface for the considered trace amounts of TNT, it was estimated that the initial surface concentration of trinitrotoluene of 100 ng/cm2 on the glass surface decreases to 12 ng/cm2 within 2.6 ± 0.3 hours due to sublimation into an open half-space. It was shown that the use of vortex sampling of vapor intensifies the sublimation of TNT from the glass surface.
{"title":"Determination of the time-dependent change in the vapor concentration of 2,4,6-trinitrotoluene during the sublimation of its traces from the glass surface","authors":"M. I. Tivileva, V. M. Gruznov, M. Baldin, A. V. Kikhtenko, I. Naumenko","doi":"10.15826/analitika.2021.25.3.003","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.3.003","url":null,"abstract":"The results of the measurements of 2,4,6-trinitrotoluene (TNT) vapor concentration over its trace amounts, called thin films, on the glass surface with a concentration of 100 ng/cm2 in a square area with a side of 1 cm over time are presented. The trace amounts of TNT on the glass were formed by applying a solution of TNT in the acetonitrile diluted with the chemically pure acetone, followed by the evaporation of the solvents. In order to measure the TNT vapor concentration, an EKHO-V-IDTS portable multibacillary gas-chromatograph with preliminary TNT vapor concentration was used. A sampling of the TNT vapor above the object was carried out with a remote vortex sampler. The vapor sample was taken from a distance of 2 cm from the glass surface. The concentration in the mode of the complete capture of TNT vapors was carried out to the stainless-steel wire mesh. The vapor concentration was determined from the chromatographic peak amplitude. It was found that the concentration of vapor over the examined surface with an area of 1 cm2 decreases from 10-13 to 10-14 g/cm3 within 2.6 ± 0.3 hours. TNT vapor concentration value of 10-14 g/cm3 corresponds to the threshold concentration of TNT vapor for the modern detectors. Based on the assumption that the vapor concentration is proportional to the amount of the TNT mass on the surface for the considered trace amounts of TNT, it was estimated that the initial surface concentration of trinitrotoluene of 100 ng/cm2 on the glass surface decreases to 12 ng/cm2 within 2.6 ± 0.3 hours due to sublimation into an open half-space. It was shown that the use of vortex sampling of vapor intensifies the sublimation of TNT from the glass surface.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.4.006
E. Shabanova, I. E. Vasil’eva
Recent achievements in the field of instrumental analytical chemistry are associated with the development of devices that register a variety of analytical signals and use a variety of information processing methods. Hence, the use of advanced mathematical techniques for the treatment of a large amount of data obtained is required. Multivariate approaches are of the greatest interest for the Earth and Life sciences since most studies are based on measuring the chemical composition of complex natural organomineral substances and describing their compositions, on which their properties directly depend. Natural objects are multidimensional in their origin, so several analysis methods and one-dimensional processing techniques are traditionally used for their study and analytical control in order to achieve the required accuracy of the results. The special mathematical techniques for processing the analytical signals in emission spectra objectively reduces costs while improving accuracy. The authors in the current paper attempt to assess the need for the use of multivariate calibrations in atomic emission spectrometry with arc discharge while simultaneously analyzing different types of objects. Different variants of calibrations are considered for two techniques of direct atomic emission determination of F as well as Li, P, B, Mn, Ni, Co, V, Cr, W, Mo, Sn, Ga, Pb, Cu, Zn, Ag, Sb, As, Tl, Ge, Bi and Cd (22 elements) in powders of rocks, loose and bottom sediments, soils, ashes, gold-silver ores and products of their processing.
{"title":"Applicability of multivariate calibrations in atomic emission spectrometry with arc discharge","authors":"E. Shabanova, I. E. Vasil’eva","doi":"10.15826/analitika.2021.25.4.006","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.4.006","url":null,"abstract":"Recent achievements in the field of instrumental analytical chemistry are associated with the development of devices that register a variety of analytical signals and use a variety of information processing methods. Hence, the use of advanced mathematical techniques for the treatment of a large amount of data obtained is required. Multivariate approaches are of the greatest interest for the Earth and Life sciences since most studies are based on measuring the chemical composition of complex natural organomineral substances and describing their compositions, on which their properties directly depend. Natural objects are multidimensional in their origin, so several analysis methods and one-dimensional processing techniques are traditionally used for their study and analytical control in order to achieve the required accuracy of the results. The special mathematical techniques for processing the analytical signals in emission spectra objectively reduces costs while improving accuracy. The authors in the current paper attempt to assess the need for the use of multivariate calibrations in atomic emission spectrometry with arc discharge while simultaneously analyzing different types of objects. Different variants of calibrations are considered for two techniques of direct atomic emission determination of F as well as Li, P, B, Mn, Ni, Co, V, Cr, W, Mo, Sn, Ga, Pb, Cu, Zn, Ag, Sb, As, Tl, Ge, Bi and Cd (22 elements) in powders of rocks, loose and bottom sediments, soils, ashes, gold-silver ores and products of their processing.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.3.006
R. Zilberg, Yuliia Teres, L. Zagitova, Y. Yarkaeva, T. V. Berestova
A voltammetric sensor based on a composite of polyarylene phthalide and graphitized carbon black Carboblack C modified with chelate complexes of L-argenato-L-alaninate of copper (II) has been developed for the recognition and selective determination of tryptophan enantiomers. The conditions for modifying the sensor are optimized, the effective surface area (A = 4.38 ± 0.06 mm2) and the effective resistance (Ret = 1.29 ± 0.08 kΩ) are calculated. The optimal conditions for recording voltammograms of tryptophan enantiomers are selected: the range of operating potentials is 0.5-1.2 V, the potential sweep rate is 20 mV/s, the holding time of the electrode in the test solution is 5 s. The electrochemical and analytical characteristics of the sensor were studied when registering differential pulse voltammograms of tryptophan enantiomers. It is shown that the dependence of the analytical signal on the concentration is linear in the range from 1.25·10-6 to 1·10-3 M with detection limits of 0.90·10-6 M for L-Trp and 0.66·10-6 M for D-Trp. The developed sensor shows the greatest sensitivity to D-Trp. The sensor has been successfully tested to determine the content of L- and D-Trp in enantiomer solutions in the presence of excipients that are part of medicines and biologically active additives. The proposed sensor allows the determination of tryptophan enantiomers in human urine and blood plasma. To evaluate the analytical capabilities of the sensor, the "entered-found" method was used. When determining tryptophan enantiomers in model solutions, the relative standard deviation does not exceed 2.3 %, and the relative error is 1.7 %. When determining D- and L-Trp in biological fluids, the relative standard deviation ranges from 0.3-1.7 %, and the relative error ranges from 0.3-5.6 %. The research results show that there is no significant systematic error.
本文研制了一种用l -琼脂- l -丙氨酸铜螯合物修饰碳黑C的聚芳酞和石墨化炭黑复合材料的伏安传感器，用于色氨酸对映体的识别和选择性测定。优化了传感器的修改条件，计算了传感器的有效表面积(A = 4.38±0.06 mm2)和有效电阻(Ret = 1.29±0.08 kΩ)。选择了记录色氨酸对映体伏安图的最佳条件:工作电位范围为0.5 ~ 1.2 V，电位扫描速率为20 mV/s，电极在测试溶液中的保持时间为5 s。在记录色氨酸对映体的差分脉冲伏安图时，研究了传感器的电化学和分析特性。结果表明，在1.25·10-6 ~ 1·10-3 M范围内，分析信号与浓度呈线性关系，l -色氨酸的检出限为0.90·10-6 M, d -色氨酸的检出限为0.66·10-6 M。所研制的传感器对D-Trp的灵敏度最高。该传感器已被成功测试，以确定L-和d -色氨酸的含量在对映体溶液中存在的赋形剂，是药物和生物活性添加剂的一部分。所提出的传感器允许测定人类尿液和血浆中的色氨酸对映体。为了评价传感器的分析能力，采用了“输入-发现”法。在模型溶液中测定色氨酸对映体时，相对标准偏差不超过2.3%，相对误差为1.7%。测定生物体液中D-和l -色氨酸时，相对标准偏差为0.3- 1.7%，相对误差为0.3- 5.6%。研究结果表明，系统误差不显著。
{"title":"Voltammetric sensor based on the copper (II) amino acid complex for the determination of tryptophan enantiomers","authors":"R. Zilberg, Yuliia Teres, L. Zagitova, Y. Yarkaeva, T. V. Berestova","doi":"10.15826/analitika.2021.25.3.006","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.3.006","url":null,"abstract":"A voltammetric sensor based on a composite of polyarylene phthalide and graphitized carbon black Carboblack C modified with chelate complexes of L-argenato-L-alaninate of copper (II) has been developed for the recognition and selective determination of tryptophan enantiomers. The conditions for modifying the sensor are optimized, the effective surface area (A = 4.38 ± 0.06 mm2) and the effective resistance (Ret = 1.29 ± 0.08 kΩ) are calculated. The optimal conditions for recording voltammograms of tryptophan enantiomers are selected: the range of operating potentials is 0.5-1.2 V, the potential sweep rate is 20 mV/s, the holding time of the electrode in the test solution is 5 s. The electrochemical and analytical characteristics of the sensor were studied when registering differential pulse voltammograms of tryptophan enantiomers. It is shown that the dependence of the analytical signal on the concentration is linear in the range from 1.25·10-6 to 1·10-3 M with detection limits of 0.90·10-6 M for L-Trp and 0.66·10-6 M for D-Trp. The developed sensor shows the greatest sensitivity to D-Trp. The sensor has been successfully tested to determine the content of L- and D-Trp in enantiomer solutions in the presence of excipients that are part of medicines and biologically active additives. The proposed sensor allows the determination of tryptophan enantiomers in human urine and blood plasma. To evaluate the analytical capabilities of the sensor, the \"entered-found\" method was used. When determining tryptophan enantiomers in model solutions, the relative standard deviation does not exceed 2.3 %, and the relative error is 1.7 %. When determining D- and L-Trp in biological fluids, the relative standard deviation ranges from 0.3-1.7 %, and the relative error ranges from 0.3-5.6 %. The research results show that there is no significant systematic error.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.4.007
I. E. Vasil’eva, E. Shabanova
The atomic emission spectrometry (AES) with arc discharge method evolution is inextricably linked with the fundamental scientific discoveries made in the 19th and 20th centuries, and it also reflects the change of scientific paradigms in a specific field of natural science – analytical chemistry. Theoretical comprehension and generalization of experimental data, along with the improving spectral equipment and methodological techniques for determining the elemental and material composition of solid geological samples, increased the accuracy of the analysis results i.e. the results were translated from qualitative to semi-quantitative and quantitative. Modern computerized equipment for direct AES with arc discharge provides minimal errors in measuring the spectral intensity due to the high stability of the excitation source of the spectra of atoms and molecules, the use of high-power polychromators and express digital recording of spectra by multi-channel detectors. However, in the commercial software of spectrometers, only the methods of manual spectra processing proposed in the 30s of the last century are programmed. That limits the possibilities of improving the analysis quality. The time has come to use the developed concept of computer processing of big spectral data, which is based on the information models of chemical analysis and the back propagation of error, in order to select the best models. Current article shows that the information models of computer spectra interpretation obtained from direct arc AES multi-element techniques of geological samples’ analysis using the injection-spillage method provide better quantitative results (category III of accuracy) due to a more complete account of spectral and matrix influences compared to the routine processing techniques.
{"title":"Stages of arc atomic emission spectrometry development as applied to the solid geological samples’ analysis","authors":"I. E. Vasil’eva, E. Shabanova","doi":"10.15826/analitika.2021.25.4.007","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.4.007","url":null,"abstract":"The atomic emission spectrometry (AES) with arc discharge method evolution is inextricably linked with the fundamental scientific discoveries made in the 19th and 20th centuries, and it also reflects the change of scientific paradigms in a specific field of natural science – analytical chemistry. Theoretical comprehension and generalization of experimental data, along with the improving spectral equipment and methodological techniques for determining the elemental and material composition of solid geological samples, increased the accuracy of the analysis results i.e. the results were translated from qualitative to semi-quantitative and quantitative. Modern computerized equipment for direct AES with arc discharge provides minimal errors in measuring the spectral intensity due to the high stability of the excitation source of the spectra of atoms and molecules, the use of high-power polychromators and express digital recording of spectra by multi-channel detectors. However, in the commercial software of spectrometers, only the methods of manual spectra processing proposed in the 30s of the last century are programmed. That limits the possibilities of improving the analysis quality. The time has come to use the developed concept of computer processing of big spectral data, which is based on the information models of chemical analysis and the back propagation of error, in order to select the best models. Current article shows that the information models of computer spectra interpretation obtained from direct arc AES multi-element techniques of geological samples’ analysis using the injection-spillage method provide better quantitative results (category III of accuracy) due to a more complete account of spectral and matrix influences compared to the routine processing techniques.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.4.008
V. G. Garanin
This paper presents the characteristics of the modern Grand-Expert spectrometer for the analysis of metals and alloys. The spectrometer has an updated optical scheme and a new spectrum analyzer to solve a wide range of analytical tasks. The analytical capabilities of the spectrometer were investigated for the analysis of steels and high-purity copper and aluminum as an example. For each of the bases, the updated optical scheme made it possible to realize new opportunities for controlling the homogeneity of the sample material and the presence of micro-inclusions on the sample surface and for determining low impurity contents in the pure metal bases. The spectrometer uses a modern semiconductor spark generator with adjustable frequency, current intensity, and duration of individual spark pulses. Spectra of metal samples for individual spark pulses were obtained in real time for the investigated sample. The operation of the spectrometer in different modes and with different exposure times was tested to select the optimal parameters of calibration characteristics. Computer control provides full synchronization of the generator mode setting, argon feeding, and spectrum registration. For steels, we selected sparking modes with high stability of spectral line intensities and analyte concentrations, and for pure metals (copper and aluminum), modes providing low detection limits of impurity elements and good stability of the results.
{"title":"Grand-Expert spectrometer for metal analysis: current status and analytical capabilities","authors":"V. G. Garanin","doi":"10.15826/analitika.2021.25.4.008","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.4.008","url":null,"abstract":"This paper presents the characteristics of the modern Grand-Expert spectrometer for the analysis of metals and alloys. The spectrometer has an updated optical scheme and a new spectrum analyzer to solve a wide range of analytical tasks. The analytical capabilities of the spectrometer were investigated for the analysis of steels and high-purity copper and aluminum as an example. For each of the bases, the updated optical scheme made it possible to realize new opportunities for controlling the homogeneity of the sample material and the presence of micro-inclusions on the sample surface and for determining low impurity contents in the pure metal bases. The spectrometer uses a modern semiconductor spark generator with adjustable frequency, current intensity, and duration of individual spark pulses. Spectra of metal samples for individual spark pulses were obtained in real time for the investigated sample. The operation of the spectrometer in different modes and with different exposure times was tested to select the optimal parameters of calibration characteristics. Computer control provides full synchronization of the generator mode setting, argon feeding, and spectrum registration. For steels, we selected sparking modes with high stability of spectral line intensities and analyte concentrations, and for pure metals (copper and aluminum), modes providing low detection limits of impurity elements and good stability of the results.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.4.012
P.V. Vashchenkо, V. А. Labusov
In atomic emission spectrometry, photodetector arrays are widely used in spectrum analyzers. A spectrum obtained with detectors of this type is a discrete sequence of digital values of photocell output signals. One way to quantify the concentration of an element in a test sample is to measure the intensity of its analytical line by integrating a region of the spectrum over several counts in the vicinity of this line or by approximating a region of the spectrum with a line shape profile. As a rule, due to the high saturation of atomic emission spectra with spectral lines, the region for calculating the spectral line intensity is limited to several counts. In the case of spectral line drift relative to the photocells of photodetector arrays, this limitation leads to an intensity measurement error, which is the greater, the smaller the number of counts used in integration. The objectives of this study are to determine the optimal size of the computational domain and develop an optimal method for calculating the line intensity to reduce the intensity measurement error. To simulate the drift of spectral lines relative to photocells, we have simulated and recorded a set of spectra of a hollow cathode lamp (Cu, Zn) with different positions of spectral lines relative to the photocells of BLPP-2000 and BLPP-4000 photodetector arrays. In each next spectrum of the set, the spectral lines were shifted relative to those in the previous spectrum by 2 and 1 μm for BLPP-2000 and BLPP-4000, respectively. It has been shown that compared to stepwise interpolation, linear interpolation significantly reduces the effect of the drift of spectral lines on the RMSD of the measured intensities for both types of arrays. In addition, this effect can be further decreased by choosing an optimal range of integration. In the linear interpolation for the selected spectral lines, the minimum measurement error due to the spectrum drift relative to the photocells of photodetector arrays for BLPP-2000 is 0.25 and 0.23% for a range of integration of 1.6 and 3.1 counts, respectively, and for BLPP-4000, it is 0.4 and 0.28% for 1.0 and 2.7 counts, respectively.
{"title":"Measuring the intensity of spectral lines from discrete counts of line spectra","authors":"P.V. Vashchenkо, V. А. Labusov","doi":"10.15826/analitika.2021.25.4.012","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.4.012","url":null,"abstract":"In atomic emission spectrometry, photodetector arrays are widely used in spectrum analyzers. A spectrum obtained with detectors of this type is a discrete sequence of digital values of photocell output signals. One way to quantify the concentration of an element in a test sample is to measure the intensity of its analytical line by integrating a region of the spectrum over several counts in the vicinity of this line or by approximating a region of the spectrum with a line shape profile. As a rule, due to the high saturation of atomic emission spectra with spectral lines, the region for calculating the spectral line intensity is limited to several counts. In the case of spectral line drift relative to the photocells of photodetector arrays, this limitation leads to an intensity measurement error, which is the greater, the smaller the number of counts used in integration. The objectives of this study are to determine the optimal size of the computational domain and develop an optimal method for calculating the line intensity to reduce the intensity measurement error. To simulate the drift of spectral lines relative to photocells, we have simulated and recorded a set of spectra of a hollow cathode lamp (Cu, Zn) with different positions of spectral lines relative to the photocells of BLPP-2000 and BLPP-4000 photodetector arrays. In each next spectrum of the set, the spectral lines were shifted relative to those in the previous spectrum by 2 and 1 μm for BLPP-2000 and BLPP-4000, respectively. It has been shown that compared to stepwise interpolation, linear interpolation significantly reduces the effect of the drift of spectral lines on the RMSD of the measured intensities for both types of arrays. In addition, this effect can be further decreased by choosing an optimal range of integration. In the linear interpolation for the selected spectral lines, the minimum measurement error due to the spectrum drift relative to the photocells of photodetector arrays for BLPP-2000 is 0.25 and 0.23% for a range of integration of 1.6 and 3.1 counts, respectively, and for BLPP-4000, it is 0.4 and 0.28% for 1.0 and 2.7 counts, respectively.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67254377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.2.009
P. A. Otopkova, A. M. Potapov, A. Suchkov, A. D. Bulanov, A. Y. Lashkov
In order to study the isotopic effects in semiconductor materials, single crystals of high chemical and isotopic purity are required. The reliability of the obtained data on the magnitude and the direction of isotopic shifts depends on the accuracy of determining the concentration of all stable isotopes. In the isotopic analysis of enriched “silicon-28” with a high degree of enrichment (> 99.99%), it is necessary to determine the impurities of 29Si and 30Si isotopes at the level of 10-3 ¸ 10-5 at. %. At this concentration level, these isotopes can be considered as impurities. It is difficult to achieve high measurement accuracy with simultaneous registration of the main and “impurity” isotopes in such a wide range of concentrations. The registration of analytical signals of silicon isotopes must be carried out in the solutions with different matrix concentrations. The use of the solutions with the high concentration of the matrix element requires the introduction of corrections for matrix noise and the drift of the instrument sensitivity during the measurement. It is possible to reduce the influence of the irreversible non-spectral interference and sensitivity drift by using the method of internal standardization. The inconsistency of the literature data on the selection criteria for the internal standard required studying the behavior of the signals of the “candidates for the internal standard” for the ELEMENT 2 single-collector high-resolution inductively coupled plasma mass spectrometer on the matrix element concentration and the nature of the solvent, as well as on the solution nebulizing time. Accounting for the irreversible non-spectral matrix noise and instrumental drift in isotopic analysis of enriched “silicon-28” and initial 28SiF4 by inductively coupled plasma mass spectrometry had allowed us to reduce by 3-5 times the random component and by more than an order of magnitude the systematic component of the measurement error in comparison with the external standard method. This made it possible to carry out, with sufficient accuracy, the operational control of the isotopic composition of enriched “silicon-28”, both in the form of silicon tetrafluoride and polycrystalline silicon obtained from it, using a single serial device in the range of isotopic concentrations 0.0001–99.999%.
{"title":"Isotope analysis of highly enriched “silicon-28” by high-resolution inductively coupled plasma mass spectrometry using an internal standard","authors":"P. A. Otopkova, A. M. Potapov, A. Suchkov, A. D. Bulanov, A. Y. Lashkov","doi":"10.15826/analitika.2021.25.2.009","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.2.009","url":null,"abstract":"In order to study the isotopic effects in semiconductor materials, single crystals of high chemical and isotopic purity are required. The reliability of the obtained data on the magnitude and the direction of isotopic shifts depends on the accuracy of determining the concentration of all stable isotopes. In the isotopic analysis of enriched “silicon-28” with a high degree of enrichment (> 99.99%), it is necessary to determine the impurities of 29Si and 30Si isotopes at the level of 10-3 ¸ 10-5 at. %. At this concentration level, these isotopes can be considered as impurities. It is difficult to achieve high measurement accuracy with simultaneous registration of the main and “impurity” isotopes in such a wide range of concentrations. The registration of analytical signals of silicon isotopes must be carried out in the solutions with different matrix concentrations. The use of the solutions with the high concentration of the matrix element requires the introduction of corrections for matrix noise and the drift of the instrument sensitivity during the measurement. It is possible to reduce the influence of the irreversible non-spectral interference and sensitivity drift by using the method of internal standardization. The inconsistency of the literature data on the selection criteria for the internal standard required studying the behavior of the signals of the “candidates for the internal standard” for the ELEMENT 2 single-collector high-resolution inductively coupled plasma mass spectrometer on the matrix element concentration and the nature of the solvent, as well as on the solution nebulizing time. Accounting for the irreversible non-spectral matrix noise and instrumental drift in isotopic analysis of enriched “silicon-28” and initial 28SiF4 by inductively coupled plasma mass spectrometry had allowed us to reduce by 3-5 times the random component and by more than an order of magnitude the systematic component of the measurement error in comparison with the external standard method. This made it possible to carry out, with sufficient accuracy, the operational control of the isotopic composition of enriched “silicon-28”, both in the form of silicon tetrafluoride and polycrystalline silicon obtained from it, using a single serial device in the range of isotopic concentrations 0.0001–99.999%.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.3.002
S. D. Tataeva, R. Z. Zeynalov, K. E. Magomedov
One of the sensitive and inexpensive methods used for the analysis of water bodies is the ionometry, the development of which is associated with the introduction of new ion-selective electrodes into the practice of potentiometric analysis. An optimized composition of the membrane for the manufacturing of a zinc-selective electrode based on polyvinyl chloride modified with 2-mercaptobenzthiazole (MPVC) is proposed with the following ratio of ingredients (in wt. %): Polyvinyl chloride - 31.7; dioctyl sebacate - 66.3; potassium tetra-p-chlorophenylborate - 0.5; MPVH - 1.5. The working range of pH was established with a minimum potential drift, which was 1.5 - 3. The slope of the electrode function was calculated as 30.1 ± 0.3 mV. According to the dependence of the electrode potential for the selected composition of the membrane on the logarithm of the zinc ion concentration, it was found that the proposed model of the electrode operates in the concentration range of 1∙10-5 - 1∙10-1 mol / L, with a detection limit of 0.65 mg / l. The stabilization time of the potential within 1 mV was 15 - 20 s. The potentiometric coefficients of the selectivity of the zinc selective electrode with respect to various ions have been determined. The conditions for the determination of zinc using the obtained sensor in alloys and wastewater were proposed. The electrode with the membrane based on polyvinyl chloride modified with 2-mercaptobenzthiazole can be used as an alternative to the industrial electrode XC-Zn-001 for the determination of zinc ions in various objects. The obtained experimental data was close in accuracy to the results obtained by the atomic absorption methods, as well as the ionometry using the industrial electrode. In conclusion, the electrode with the membrane based on polyvinyl chloride modified with 2-mercaptobenzthiazole can be used as an alternative to XC-Zn-001.
{"title":"Potentiometric sensor for lead ions determination","authors":"S. D. Tataeva, R. Z. Zeynalov, K. E. Magomedov","doi":"10.15826/analitika.2021.25.3.002","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.3.002","url":null,"abstract":"One of the sensitive and inexpensive methods used for the analysis of water bodies is the ionometry, the development of which is associated with the introduction of new ion-selective electrodes into the practice of potentiometric analysis. An optimized composition of the membrane for the manufacturing of a zinc-selective electrode based on polyvinyl chloride modified with 2-mercaptobenzthiazole (MPVC) is proposed with the following ratio of ingredients (in wt. %): Polyvinyl chloride - 31.7; dioctyl sebacate - 66.3; potassium tetra-p-chlorophenylborate - 0.5; MPVH - 1.5. The working range of pH was established with a minimum potential drift, which was 1.5 - 3. The slope of the electrode function was calculated as 30.1 ± 0.3 mV. According to the dependence of the electrode potential for the selected composition of the membrane on the logarithm of the zinc ion concentration, it was found that the proposed model of the electrode operates in the concentration range of 1∙10-5 - 1∙10-1 mol / L, with a detection limit of 0.65 mg / l. The stabilization time of the potential within 1 mV was 15 - 20 s. The potentiometric coefficients of the selectivity of the zinc selective electrode with respect to various ions have been determined. The conditions for the determination of zinc using the obtained sensor in alloys and wastewater were proposed. The electrode with the membrane based on polyvinyl chloride modified with 2-mercaptobenzthiazole can be used as an alternative to the industrial electrode XC-Zn-001 for the determination of zinc ions in various objects. The obtained experimental data was close in accuracy to the results obtained by the atomic absorption methods, as well as the ionometry using the industrial electrode. In conclusion, the electrode with the membrane based on polyvinyl chloride modified with 2-mercaptobenzthiazole can be used as an alternative to XC-Zn-001.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.15826/analitika.2021.25.4.004
E. V. Polyakova, O. V. Pelipasov
The creation and implementation of new sources of sample excitation and spectrometers based on them into the practice of analytical laboratories raises many questions for researchers about the obtained analytical characteristics of new equipment and analysis methods. The most important characteristics of any method include detection limits, accuracy and reproducibility of the results obtained. Matrix elements can have a significant effect on these parameters. The paper shows a comparison of the change in the intensities of analytical lines of elements in the presence of matrix elements with ionization potentials of 5.13 - 10.48 eV (Na, Cu, Pb, Cd, Zn, In, Ga, Bi) in the concentration range of 0 - 1 wt %. on commercially available atomic emission spectrometers with microwave plasma Grand-MP ("VMK-Optoelektronika") and Agilent MP-AES 4100 (Agilent Technologies). It is shown that the magnitude of the matrix effect in these excitation sources depends on the ionization potential of the matrix element and the total energy of the analyte line. A significant effect of matrix elements with a concentration of up to 1% wt. on the intensity of spectral lines of atoms and ions of the sample. Elements with medium and high ionization energies practically do not affect the intensity of atomic spectral lines of impurity elements and lead to a decrease in the intensity of ionic lines. The influence of easily ionized elements is more pronounced - both depressing and amplifying effects are observed, probably caused by both a change in the concentration of electrons in the plasma, leading to a linear change in the equilibrium between atoms and ions, and a decrease in the plasma temperature. An increase in the power supplied to the plasma on the Grand-MP spectrometer leads to a decrease in the effect of easily ionized elements on the intensity of the spectral lines of the elements. It is shown that the plasma in the Grand-MP spectrometer has better resistance to matrix influences as compared to the Agilent MP-AES 4100, which is associated with a large plasma volume and a higher input power.
{"title":"Comparison of matrix effects on atomic emission spectrometers with nitrogen microwave induced plasma","authors":"E. V. Polyakova, O. V. Pelipasov","doi":"10.15826/analitika.2021.25.4.004","DOIUrl":"https://doi.org/10.15826/analitika.2021.25.4.004","url":null,"abstract":"The creation and implementation of new sources of sample excitation and spectrometers based on them into the practice of analytical laboratories raises many questions for researchers about the obtained analytical characteristics of new equipment and analysis methods. The most important characteristics of any method include detection limits, accuracy and reproducibility of the results obtained. Matrix elements can have a significant effect on these parameters. The paper shows a comparison of the change in the intensities of analytical lines of elements in the presence of matrix elements with ionization potentials of 5.13 - 10.48 eV (Na, Cu, Pb, Cd, Zn, In, Ga, Bi) in the concentration range of 0 - 1 wt %. on commercially available atomic emission spectrometers with microwave plasma Grand-MP (\"VMK-Optoelektronika\") and Agilent MP-AES 4100 (Agilent Technologies). It is shown that the magnitude of the matrix effect in these excitation sources depends on the ionization potential of the matrix element and the total energy of the analyte line. A significant effect of matrix elements with a concentration of up to 1% wt. on the intensity of spectral lines of atoms and ions of the sample. Elements with medium and high ionization energies practically do not affect the intensity of atomic spectral lines of impurity elements and lead to a decrease in the intensity of ionic lines. The influence of easily ionized elements is more pronounced - both depressing and amplifying effects are observed, probably caused by both a change in the concentration of electrons in the plasma, leading to a linear change in the equilibrium between atoms and ions, and a decrease in the plasma temperature. An increase in the power supplied to the plasma on the Grand-MP spectrometer leads to a decrease in the effect of easily ionized elements on the intensity of the spectral lines of the elements. It is shown that the plasma in the Grand-MP spectrometer has better resistance to matrix influences as compared to the Agilent MP-AES 4100, which is associated with a large plasma volume and a higher input power.","PeriodicalId":37743,"journal":{"name":"Analitika i Kontrol","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67253967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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