Matrix-matched Method Research Articles

Determination of trace elements in superalloys by inductively coupled plasma mass spectrometry with micro-reaction pretreatment

Due to complex pretreatment processes and the consumption of large amounts of high-purity chemical reagents, traditional analytical methods for determining trace element concentrations in superalloys face severe challenges. In this paper, a micro-reaction pretreatment method was developed by using a micro-reaction sealed digestion vessel under micro-pressure. The mass of the samples and the volume of acid used to dissolve the superalloys were significantly reduced. The appropriate amount of digestive acid for micro-reaction and three generalized pretreatment methods were studied. The quantitative dilution process was optimized to minimize errors through meticulous weighing procedures using a high-precision balance, and the homogeneity of the samples was verified by using Ni-based superalloy standards and general samples. Sc, Rh, and Re were selected for internal standard correction, and the matrix effect was corrected by the matrix matching method. Moreover, the mass spectral interference caused by polyatomic ions was eliminated by He collision mode. The linear correlation coefficients of the calibration curves were above 0.9995, with linear coefficients ranging from 0.2 to 100 ng/g. The detection limits for the method ranged from 0.0042 to 0.13 μg/g, and the quantification limits ranged from 0.014 to 0.41 μg/g. The results showed the precision and reliability of the newly established green micro-reaction pretreatment scheme for the determination of Ga, As, In, Sn, Sb, Tl, Pb, and Bi in nickel-based superalloys together with inductively coupled plasma mass spectrometry. The micro-reaction test results of the various groups were consistent with those of the traditional methods, and the relative standard deviation (RSD, n = 11) was less than 10 %. In addition to reducing acid consumption and increasing the test solution utilization rate by ten times, the micro-reaction method was much more accessible from cross-contamination and intensive manual work, so it has shown great potential for application in intelligent and automatic batch testing of trace elements in superalloys.

Development of UV‐Vis spectroscopy-based analysis method for determination of tin(IV) in epilobium parviflorum (hoary willowherb) tea using deep eutectic solvent based preconcentration

In this study, a UV–Vis Spectroscopy-based method was developed for the determination of tin(IV) in epilobium parviflorum tea samples after preconcentration. The preconcentration process was carried out using the liquid-liquid microextraction technique. Before starting the analysis, optimization studies were carried out for the variables likely to affect the experimental results. As a result of the analyzes performed under optimum conditions, the detection limit of our method was calculated as 16.83 μg/L. The percent relative standard deviation value was calculated as 1.25% (n = 8) and linearity was found in the range of 10–1000 μg/L. Recovery experiments were performed on epilobium parviflorum tea samples using the matrix matching method. As a result of the analyzes made on teas belonging to three different brands, recovery results ranging from 92 to 117% were obtained.

Determination of Cadmium Content in Pork by Graphite Furnace Atomic Absorption Spectrometry Combined with Matrix Matching Method and Its Health Risk Assessment

Determination of Cadmium Content in Pork by Graphite Furnace Atomic Absorption Spectrometry Combined with Matrix Matching Method and Its Health Risk Assessment

Development of an analytical method for the determination of pesticides in tropical fruits by LC-QTOF-MS/MS after QuEChERS extraction sample cleanup and DLLME preconcentration

In this study, QuEChERS extraction was combined with dispersive liquid–liquid microextraction (DLLME) to extract pesticides from tropical fruits for determination by a highly accurate and sensitive liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS/MS) system. The QuEChERS method served as a matrix clean-up tool and the DLLME method preconcentrated the analytes for their determination at trace levels. All parameter variables of the DLLME method were optimized to improve the extraction output and lower the limits of detection and quantification (LOD and LOQ) for all the analytes. Under the optimum experimental conditions, the LOD and LOQ values were found in the range of 0.004–0.013 and 0.27–0.61 μg l−1, respectively. The detection limits achieved by direct LC-QTOF-MS/MS analysis were increased by about 10–260 folds using the optimized DLLME method. To assess the accuracy and applicability of the developed method, spike recovery experiments on tropical fruits were carried out. The matrix matching calibration method was used to enhance the quantification accuracy of the analytes in kiwi, pineapple, and mango matrices, with percent recoveries ranging between 89 and 117%.

Development of an analytical strategy for the determination of trace lead in hibiscus tea extract by double slotted quartz tube assisted flame atomic absorption spectrometry after manganese ferrite based dispersive solid phase extraction

In this study, a manganese ferrite (MnFe2O4) based dispersive solid phase extraction method (MF-DSPE) was proposed for the determination of lead (Pb) ions in hibiscus tea by double slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS). The MnFe2O4 nanoparticles used as sorbent were produced in high yields using a green and friendly microwave synthesis procedure. The limit of detection (LOD) was found to be 14.2 µg/L under the optimal conditions. Recovery experiments were performed to assess the applicability of the developed method using hibiscus tea as test sample matrix. High recovery results were obtained by applying the matrix matching calibration method. Thanks to the developed MF-DSPE-SQT-FAAS method, the detection sensitivity for lead was improved by about 108-folds according to the comparison of the slopes of the calibration plots of the FAAS and MF-DSPE-SQT-FAAS systems.

A Simplified Method for Determining Blood-to-Plasma Ratios in vitro and ex vivo by Matrix Matching with Blank Blood or Plasma.

This work describes a simplified, 96-well plate method for determining the blood-to-plasma concentration ratio (BP ratio) for small molecules. The need for calibration curves was eliminated using a matrix-matching approach in which blood samples were mixed with blank plasma and plasma samples were mixed with blank blood. As a result, both blood- and plasma-origin samples shared an equivalent matrix ahead of bioanalysis. In the in vitro assay, identical sample matrices were achieved by using the same source of blank plasma and blood. In humans, a good correlation (R2 = 0.84) was observed between the data obtained in this matrix-matching method and literature values for 11 commercial compounds possessing a wide range of logD values across multiple chemical classes. In addition, this method showed good agreement with in vitro BP ratios for 10 proprietary compounds determined radiometrically (R2 = 0.72) in human and preclinical species. Finally, the in vitro matrix matching method compared favorably to BP ratios determined ex vivo for 13 proprietary and literature compounds (R2 = 0.87) in rat. This method, suitable for in vitro and ex vivo BP ratio determinations, is operationally efficient, robust, and a useful improvement upon previously published methods.

A Simple and Effective Quantification of Water‐Soluble Rhodium in Soil Samples by Magnetic‐Colloidal‐Gel‐Assisted Dispersive Solid Phase Extraction

AbstractIn this study, a simple, sensitive and environmentally friendly method was developed for the determination of water‐soluble rhodium in soil samples. For this purpose, rhodium was preconcentrated/separated by a dispersive solid phase extraction method (dSPE) and determined by an atomic absorption spectrophotometer with flame atomizer, equipped with a slotted quartz tube (SQT‐FAAS). In the dSPE method, a magnetic colloidal gel (magnetic nanofluid) was produced by mixing Fe3O4 based magnetic nanoparticles (MNP), and deep eutectic solvent (DES) obtained from the mixture of choline chloride and phenol (1 : 3). The optimized system showed good linearity in the concentration range of 17–447 μg/kg. While recording a detection limit (LOD) of 4.26 μg/kg, an over 200‐fold improvement in the detection power was obtained based on the comparison of LODs of the developed method and FAAS. Applicability and accuracy of the developed method were validated by spike recovery results that fell in the range of 89–106 %, using the matrix matching method to boost quantification accuracy in the soil samples.

Determination of trace lead(II) in cleavers (Galium aparine) tea by Uv-vis spectrophotometry after preconcentration with deep eutectic solvent/DTZ probe-based liquid-liquid microextraction

In this study, a method was developed for the determination of trace lead(II) levels in cleavers (Galium aparine) tea by UV-Vis Spectrophotometry after preconcentration with probe-based liquid-liquid microextraction (LLME) method. Deep eutectic solvent/dithizone (DES/DTZ) solution was used in the preconcentration of lead-containing samples. DES solution was prepared using choline chloride and phenol. The detection limit of the method for lead(II) was calculated as 1.53 µg/L under the optimum conditions applied in the study. In addition, the percent relative standard deviation value was found to be 4.21% (n = 8). Three different brands of cleavers (Galium aparine) were provided to be used in the analyzes to be made within the scope of the study. Samples containing 10, 30, and 50 µg/L lead solutions were prepared in tea extracts to be used in recovery experiments. Percent recovery values were primarily calculated against pure water. Then, the matrix matching method was applied between tea samples belonging to different brands to evaluate the performance of the method we developed in different matrix environments. Satisfactory recovery results were obtained between 97% and 104% at three different concentrations. With the developed method, lead analysis can be performed satisfactorily in Cleavers (Galium aparine) tea in different matrix environments.

Zirconium oxide/titanium oxide nanorod decorated nickel foam as an efficient sorbent in syringe filter based solid-phase extraction of pesticides in some vegetables

In the present study, an interesting, rapid and innovative syringe filter solid-phase extraction method was developed based on the novel sorbent of zirconium oxide/titanium oxide nanorod decorated over nickel foam (ZrO2-TiO2 NR @Ni foam SF-SPE). The extraction process was conducted based on a pulled-up and pushed-down process. The proposed ZrO2-TiO2 NR @Ni foam was prepared based on one-pot method and accordingly SEM, EDX and FT-IR techniques were utilized for characterization. The main parameters which affect the extraction process including pH, the number of sample solution pulled-pushed times, ionic strength, sample volume, elution solvent type and volume on the extraction efficiency of the target pesticides were investigated via matrix match method in samples. Under the optimum condition using matrix match strategy, the linear range of 5–400 µg kg−1, LODs and LOQs in the range of 0.45–0.55 µg kg−1 and 1.52–1.76 µg kg−1 for cucumber and 0.36–0.54 µg kg−1 and 1.23–1.75 µg kg−1 for tomato were achieved. The intra–day and inter–day precisions were evaluated at two different concentration levels (50 and 100 μg kg−1 of each analyte) on the same day and five distinct days respectively. The obtained RSD (%) values were ≤3.7 % for intra-day (n = 7) and ≤4.2 % inter-day (n = 5) precisions. The relative recoveries of 91.8–99.1 % were acquired which confirmed high potential of the method in simultaneous extraction of the pesticides in cucumber, tomato.

Impact Localization in Anisotropic Composites With Time Difference Matrix Matching and Edge Accuracy Optimization

Composites play an important role in the development of modern science and technology, but the special anisotropy leads to difficulties in impact localization. To achieve impact localization on composite materials, this paper proposes a time difference matrix matching method with edge accuracy optimization. The method uses the propagation characteristics of Lamb wave in composite materials to solve the direction dependence of wave velocity. To overcome the anisotropy, the time difference feature vector of each element of the composite material is obtained by grid division, and the impact location is found according to the similarity. In addition, edge accuracy optimization is proposed to further improve localization accuracy. Using 49 points in the 800mm×800mm composite area for 147 impact tests, the result shows that the average error can reach 0.532cm, and the variance is 0.217cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Determination of dazomet and its metabolite methyl isothiocyanate residues in plant-derived foods by gas chromatography-triple quadrupole mass spectrometry

基于气相色谱-三重四极杆质谱建立了同时快速测定植物源性食品中棉隆及其代谢物异硫氰酸甲酯残留量的方法。对样品前处理及色谱条件进行了优化,蔬菜、水果、谷物、坚果、茶叶和香辛料样品经乙酸乙酯提取,离心后上清液经乙二胺-N-丙基硅烷化硅胶、石墨化炭黑、十八烷基键合硅胶和无水硫酸镁分散固相萃取净化,经DB-17MS色谱柱(30 m×0.25 mm×0.25 μm)分离,采用EI源,在多反应监测(MRM)模式下检测,基质匹配外标法定量。在优化实验条件下,目标化合物在0.005~1 mg/L范围内的线性关系良好,相关系数均大于0. 99,方法定量限为0.01 mg/kg。空白样品在4个添加水平下的平均回收率为74.2%~117.2%,相对标准偏差(n=6)为2.8%~9.0%,方法的准确度和精密度符合农药残留测定要求。应用建立的方法对实验室日常样品大白菜、韭菜、豇豆、油麦菜、茄子、姜、芹菜、马铃薯、橙、猕猴桃、西红柿、辣椒、大米、茶叶、杏仁和孜然各6个进行检测,均未检出目标物。该方法具有操作简单、快速、灵敏、准确的特点,解决了已有方法中需采用两种前处理方法、两套设备进行检测的不足,能满足植物源食品中棉隆及其代谢物异硫氰酸甲酯的检测要求。

An efficient 3D adsorbent foam based on graphene oxide/AgO nanoparticles for rapid vortex-assisted floating solid phase extraction of bisphenol A in canned food products.

In this study, a three-dimensional adsorbent was developed based on graphene oxide/AgO nanoparticles over interconnected nickel foam (GO/AgO@Ni foam) for rapid and efficient vortex assisted floating solid phase extraction of bisphenol A in canned food products prior to high performance liquid chromatography with a fluorescence detector. The analytical techniques scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FT-IR) were used for characterization of the synthetized GO/AgO@Ni foam. The effect of proficiency factors including pH, foam size, vortexing time, salt addition, sample volume, desorption type and volume, and desorption time on the extraction efficiency of bisphenol A were explored through the matrix match method. Under the above experimental conditions, the figures of merit of the method were acquired as LODs (S/N = 3) of 0.18-0.84 μg kg-1, LOQs of 0.61-2.81 μg kg-1 (S/N = 10), linear ranges of 0.5-500 μg kg-1, and enrichment factors of 235.5-244.9. The inter-day precision values (RSD%, n = 7) of 2.5-3.6 and the intra-day precision (%) of (5 days and seven replicates for each day) 2.8-3.8 were achieved for bisphenol A at a concentration of 50 μg kg-1. The relative recoveries of 94.0% to 99.6% were obtained for the canned food samples.

Influence Factors and Elimination on Iron Content Using ICP-AES Method in Oilfield Produced Water

ICP-AES method can be used to determine multiple metallic elements simultaneously, and has the advantages of high sensitivity, good repeatability and high accuracy. In the paper, the detection limit of iron content was determined by stepwise dilution method. The influence of the cationic concentration on the determination of iron element was studied, and the matrix matching method was proposed to eliminate the influence. The results show that, the determination limit of Iron element is 0.01 mg·L-1. Because the other cationic content is several times or even tens of times as much as iron ions, it has a great influence on the determination results of Iron element. The effects of cationic concentration can be effectively eliminated by establishing a standard curve using matrix matching. After digestion pretreatment on the oil and gas field produce water, The standard adding recovery rate was between 95% and 105%, and the RSD is less than 4%. Compare this method with o-phenanthroline spectrophotometry, its relative error is within 5%. Therefore, ICP-AES method can fully meet the requirements of determination of iron content in oil field produce water, and greatly improves the efficiency and accuracy of the laboratory analysis of oil and as field wastewater.

Determination of Fenobucarb and Chlorbenside in Wastewater and Lake Water Samples by Gas Chromatography Mass Spectrometry

The advent of pesticide production on large scale has contributed immensely to the quality and quantity of agricultural products, and averting diseases that stem from pest vectors. Despite these benefits, inappropriate or excessive usage of these chemicals could have negative impacts on humans and other organisms in the environment. Thus, this study was designed to detect and quantify fenobucarb and chlorbenside in wastewater and lake water samples by a gas chromatograph system coupled to a mass selective detector. A suitable temperature program was used to elute the two analytes at distinct retention times, and satisfactory system performance values were obtained under optimum conditions. All standard solutions and spiked samples were gravimetrically prepared in order to enhance the accuracy of quantification. The analytes were not detected in the two test samples, but spike recovery experiments were performed to validate the accuracy of the method. Percent recoveries calculated using the external calibration method were below 75%. Thus, matrix matching calibration method was used to mitigate matrix effects to obtain approximately 100% recovery results for five different spike concentrations.

A Sensitive Microextraction Method Using Effervescence Tablets to Disperse Fe3O4 Nanoparticles for Cadmium Determination in Lake Water Samples

AbstractIn this study, an effective and sensitive method was developed for the preconcentration of cadmium in flame atomic absorption spectrometer system combined with a 5‐holes cut slotted quartz tube (SQT‐FAAS). For this aim, a dispersive solid‐phase microextraction method based on a magnetic effervescent tablet consisting of Fe3O4 nanoparticles (EA‐MNP‐dSPME) was proposed. In the developed microextraction method, the dispersion of the nanoparticles used as adsorbents was assisted by the effervescent tablets generated from a mixture of sodium carbonate and sodium dihydrogen phosphate dihydrate. In order to obtain the highest extraction and instrumental output, all variables that affect the efficiency was investigated comprehensively and optimum conditions were determined with univariate optimization steps. The detection power of the conventional FAAS system was enhanced about 135 folds with respect to the LOD value of the developed method (0.34 ng mL−1) obtained under the optimum conditions. The EA‐MNP‐dSPME method presented high reproducibility with a low %RSD value calculated as 8.1 %. In order to validate the accuracy and applicability of the method, matrix matching method based recovery studies were carried out using the lake water samples taken from Horseshoe Island. The percent recovery results reported between 99.9–104.3 % with percent relative standard deviation below 7.9 % indicated the developed method‘s applicability for the accurate and precise determination of cadmium.

Detect 15 pesticides fungicide in edible fungi by multiplug filtration clean-up pretreatment technology with ultra-high performance liquid chromatography-tandem mass spectrometry

To establish a method for determination of 15 pesticides residue in edible fungi by multiplug filtration clean-up(m-PFC) pretreatment technique with ultra-high performance liquid chromatography-tandem triple quadruple mass spectrometry(UPLC-MS/MS). The interferences of edible fungus samples were removed by extracting with acetonitrile and filtration type extraction column, which were fat, carbohydrates, water-soluble vitamins. Samples were separated with column of Waters ACQUITY UPLC®HSS T3(2.1 mm×100 mm, 1.8 μm), and were scanned by multiple reaction monitoring mode(MRM). Samples were quantified with matrix matching standard curve external standard method. The recoveries of 15 target compounds at the spiked levels of 10, 20, 50 μg/kg were 82.5%-118.5%, and the relative standard deviations were between 6.1% and 23.1%(n=6). The detection limit of 15 target compounds was 1-3 μg/kg, and the limit of quantification was 3-10 μg/kg. This method improves the efficiency of pretreatment, has good stability and high sensitivity, and could be used for the detection of 15 pesticides in edible fungi.

Accurate and sensitive determination of cobalt in urine samples using deep eutectic solvent-assisted magnetic colloidal gel-based dispersive solid phase extraction prior to slotted quartz tube equipped flame atomic absorption spectrometry

In this study, a colloidal gel of magnetic Fe3O4 nanoparticles was used in the development of a simple and accurate dispersive solid phase extraction method for the extraction/preconcentration of trace levels of cobalt ions in urine samples. The eluted cobalt ions were determined by slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS). The effects of the type and volume of buffer solution, volume of magnetic colloidal gel, type and period of mixing, concentration and volume of the eluent were investigated and optimized to obtain the best experimental outputs. Under the optimum conditions, the limits of detection and quantification were found as 4.6 and 15 ng mL−1, respectively. The developed method provided a 61.5 folds enhancement in the detection power of the flame atomic absorption spectrophotometry. Method validation was performed by spiking experiments using matrix matching method. The percent recoveries were found to be close to 100% for the spiked samples, which validate the accuracy and the applicability of the developed method to the urine samples.

Determination of domoic acid in shellfish by liquid chromatography- tandem mass spectrometry coupled with dispersive solid phase extraction

A method utilizing liquid chromatography-tandem mass spectrometry(LC-MS/MS) coupled with dispersive solid phase extraction for quantitative analysis of domoic acid in four kinds of shellfish was established. The sample of 0. 1 g was extracted with 25% methanol aqueous solution, the extract was purified by dispersive solid phase extraction with 50 mg HLB and 5 mg GCB, and then filtered through a PTFE membrane. The analytes were separated on a C_(18) column(100 mm×2. 1 mm, 1. 9 μm), and detected in selected reaction monitoring(SRM) mode via positive electrospray ionization. The matrix matching and external standard method was used for quantitation. Domoic acid showed good linearity in the concentration range between 1. 0 ng/mL and 50. 0 ng/mL with correlation coefficients higher than 0. 9994. The detection limits of domoic acid in shellfish was 5 μg/kg. The inter-and intra-day recoveries were 91. 6%-109. 2% and 90. 9%-109. 3%, respectively. The inter-and intra-day ralitive standard deviations(RSDs) were lower than 8. 2% at spiked concentrations of 20, 50 and 100 μg/kg. The method is accurate, fast, easy to operate, which can satisfy the requirements of public health emergency testing or routine testing.

Multi-class pesticide analysis in cannabis oil using coated blade spray and solid-phase microextraction with liquid chromatography coupled to mass spectrometry

The application of solid-phase microextraction (SPME) coupled to mass spectrometry to provide a high-throughput and cost-effective solution to multi-residue analysis of pesticides in cannabis oil samples has not been extensively explored. In this work, the method development steps for the extraction of an initial target list of 74 pesticides from cannabis oil via SPME for analysis with both LC-MS/MS and coated blade spray (CBS) are presented. The exploration of a washing step to remove adhered oil whilst minimally desorbing extracted analytes along with the implementation of central composited design investigation to examine compound extraction kinetics in the non-polar matrix yielded a workflow that was validated via both instrumental techniques. Of the initial target list, 37 pesticides were found to be suitable for screening or quantitation via CBS with performance validated via LC-MS/MS. The majority of compounds were found to meet the EU SANTE guidelines for analysis (i.e. linearity, precision, accuracy) whilst reaching limits of quantitation below or at Health Canada minimum regulatory limits (majority at 10 ng/mL). Examination of factors contributing to poor quantitation of pesticides via CBS are shared and explored, such as contributing isobaric interference sourced from plant byproducts and carrier oil, and comparison of signal-to-noise values achieved in cannabis oil when compared to the cannabis-free medium-chain triglyceride oil used as a carrier oil to stress the importance of matrix-match method development.

Survey of protein-based sport supplements for illegally added anabolic steroids methyltestosterone and 4-androstenedione by UPLC-MS/MS

There is some evidence that marketable supplements contain hormones not declared on the product label. The presence of these androgenic anabolic steroids (AAS) in sports supplements can be considered an adulteration and affect the health of consumers, who are predominantly athletes. This study aimed to measure anabolic hormones (methyltestosterone and 4-androstenedione) in sport supplements. Ultra Performance Liquid chromatography coupled mass spectrometry (UPLC-MS/MS) with electrospray ionization (ESI) in positive mode was employed under the Multiple Reaction Monitoring (MRM) ion program. To overcome matrix effects and quantify the selected analyte, the calibration curve was made using Matrix Match method. The LOQ and LOD were 1 ng/g and 0.3 ng/g for both analytes. The recovery of 4-androstenedione and methyltestosterone was in the range of 86.87–107.35 and 77.31–113.98, respectively. In terms of reproducibility, CV % for 4-androstenedione and methyltestosterone ranged from 6.56 to 16.87% and 1.45–15.12%, respectively. 4-androstenedione was found in 11 samples including 9 whey as 1.578 ± 0.154 ng/g and 2 whey albumin samples with an amount of 1.134 ng/g and 1.474 ng/g. Consequently, continuous controlling of sport supplements comprising intentionally or unintentionally added androgens could be important for health and discuss in the context of compliance with anti-doping.