Microwave Acid Digestion Method Research Articles

Experimental study for inorganic and organic profiling of toy makeup products: Estimating the potential threat to child health.

Inorganic elements are added to toys as impurities to give desired stability, brightness, flexibility, and color; however, these elements may cause numerous health issues after acute or chronic exposure. In this study, the inorganic profile of 14 elements (Al, As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Se, Sb, Pb, and Zn) in 63 toy makeup products was identified by inductively coupled plasma-mass spectrometry after microwave acid digestion method. Additionally, organic allergen fragrance was investigated by gas chromatography-mass spectrometry. The systemic exposure dosage (SED), margin of safety (MoS), lifetime cancer risk (LCR), hazard quotient (HQ), and hazard indices were used to assess the safety evaluation. Then, 57 out of 63 samples (90.48%) exceeded the limits at least for one toxic element with descending order Ni > Cr > Co > Pb > Sb > Cd > As > Hg. The SED values were compared with tolerable daily intake values and remarkably differences were found for Al and Pb. The MoS values for 57.15% of samples exceeded the limit value for Al, As, Cd, Co, Hg, Mn, Sb, and Zn elements. The LCR values were observed at 100% (n = 63), 79.37% (n = 50), 85.71% (n = 54), 77.78% (n = 49), and 18.87% (n = 10) for Cr, Ni, As, Pb, and Cd, respectively. Also, the skin sensitization risks were obtained for Cr and Ni at 26.980% (n = 17) and 9.52% (n = 6), respectively. The HQ values for 80% of samples were found to be ≥ 1 at least for one parameter. The investigation of fragrance allergens in samples did not show any significant ingredients. As a result, toy makeup products marketed in local stores were found to be predominantly unsafe. Children should be protected from harmful chemicals by regular monitoring and strict measures.

EVALUATION OF OCCUPATIONAL EXPOSURE TO TIO2 NANOPARTICLES: MICROWAVE-ASSISTED ACID DIGESTION METHOD ON AIR MEMBRANE FILTERS

Titanium dioxide (TiO2) nanoparticles have been extensively used in various industrial sectors and applications, including cosmetics, catalysts, food additives, inks, paints, and coatings. However, the International Agency for Research on Cancer (IARC) has classified TiO2 nanoparticles as a potential carcinogen for humans, meaning they may cause cancer and pose serious health complications, particularly for manufacturing workers. This highlights the need for better evaluation to determine worker exposure. In this study, suspended TiO2 nanoparticles were sampled using a nanoparticle respiratory deposition (NRD) sampler fitted with specially designed membrane filters and analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The digestion method used for titanium element recovery after nanoparticle sampling is crucial for optimal ICP-MS analysis. Therefore, this study aimed to investigate the most suitable digestion method. A microwave-acid digestion method using concentrated nitric acid and concentrated hydrochloric acid at a 7:4 ratio, with a run time of 30 minutes and the temperature set to 200°C showed remarkable titanium recovery compared to other methods. These findings may pave the way for optimal analysis of suspended TiO2 nanoparticles in assessing occupational exposure while promoting sustainability and eco-friendliness in resource utilization.

Theoretical Health Risk Assessment Based on Potentially Toxic Element Profiling of Cosmetic Products in Istanbul Street Bazaars.

Toxic elements that pose a potential threat to human health are found as impurities in various cosmetic products. In this study, the inorganic profile of 19 elements (Li, B, Mg, Al, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Sb, Ba, Hg, and Pb) in 90 cosmetic products (lipsticks, lip glosses, lip pencils and eye shadows) were detected by inductively coupled plasma-mass spectrometry after microwave acid digestion method and hazard indices (HI) of 9 toxic elements (Pb, Cd, Cr, Ni, Co, As, Hg, Sb, and Al) were calculated for the assessment of theoretical health risk. Satisfactory method performance parameters were found for each analyte. The results were compared with the maximum permissible limits set by regulatory agencies; 38 of 41 lip products (92.68%) and all eye shadows (n = 49) exceeded the established limits. The HI was found to be ≥ 1 in 82.76% of lip products for oral exposure, whereas HI was ≤ 1 for dermal exposure in all lip products (n = 41) and only one eye shadow sample was ≥ 1 (2.04%). Remarkable results were also detected for 19 elements in this study, which conducted a comprehensive inorganic profiling for the first time. Wide-range concentrations of Mg, Al, Ba, Mn, Cu, Zn, and Sr elements were remarkable. HI values were firstly brought out in this study, although Al, as a well-known toxic element, has not been listed in regulations yet. In conclusion, it is obviously seen that continuous monitoring of cosmetics is crucial not only for toxic elements but also for other essential or non-toxic elements to prevent consumers from long-term exposure.

Performance Parameters of Inductively Coupled Plasma Optical Emission Spectrometry and Graphite Furnace Atomic Absorption Spectrometry Techniques for Pd and Pt Determination in Automotive Catalysts.

Palladium (Pd) and platinum (Pt) are extensively used as catalysts in the petrochemical and automotive industries, and due to high demand for them on the market, their recycling from spent supported catalysts is clearly needed. To assess the content of Pd and Pt in catalysts in order to establish their commercial value or to evaluate the recovery efficiency of technologies used for recycling, reliable analytical methods for determination of these elements are required. Spectrometric methods, such as inductively coupled plasma optical emission spectrometry (ICP-OES) and graphite furnace atomic absorption spectrometry (GFAAS) are powerful tools that can be employed for the determination of Pd and Pt in various sample matrices. However, these methods allow only the injection of liquid samples. In this regard, the digestion of solid sample by microwave-assisted acid extraction procedures at high pressures and temperatures is often used. In this study, a microwave acid digestion method was optimized for the extraction of Pd and Pt from spent catalysts, using a four-step program, at a maximum 200 °C. The resulting solutions were analyzed using ICP-OES, at two different wavelengths for each metal (Pd at 340.458 and 363.470 nm, and Pt at 265.945 and 214.423 nm, respectively) and using GFAAS (Pd at 247.64 nm, Pt at 265.94 nm). Five types of spent catalyst were analyzed and the standard deviations of repeatability for five parallel samples were less than predicted relative standard deviations (PRSD%) calculated using Horvitz’s equation for all the analyzed samples.

Determination of Major, Minor, and Toxic Elements in Tropical Fruits by ICP-OES After Different Microwave Acid Digestion Methods

Fruits contain nutrients, minerals, trace elements, vitamins, and phytochemicals that are important in terms of human health. When fruits are consumed in a balanced diet, they have a positive effect with regard to reducing disease risk. As a result of heavy metal contamination of the environment, they can be a potential source of toxic elements so it is important to determine the toxic, essential, and trace elements in fresh fruit and commercial fruit products such as fruit juice, marmalade. This study aims to determine the concentrations of Al, B, Ca, Cu, Fe, K, Mg, Mn, Na, Zn, P, and S in tropical fruits (tamarind (Tamarindus indica), star fruit (Averrhoa carambola), golden berry (Physalis peruviana), kumquat (Citrus japonica), dragon fruit (Hylocereus undatus), passion fruit (Passiflora edulis)) by using inductively coupled plasma optical emission spectrometry (ICP-OES) after different microwave acid digestion procedures. The efficiencies of digestion in tropical fruit samples were investigated and compared. Six milliliters of HNO3 + 2 mL of H2O2, 6 mL of HNO3 + 2 mL of HCl, 8 mL of HNO3, 8 mL of HNO3 + 4 mL of H2O2 (30%), 8 mL of HNO3 + 4 mL of HCl, and 12 mL of HNO3 were used for microwave acid digestion procedures. Microwave digestion procedures were applied for the analysis of seventy-two tropical fruit samples purchased in triplicate for each tropical fruit and major, toxic, and minor element contents of tropical fruits were determined. The parameters of the merit evaluated were validated according to limits of detection (LOD) and limits of quantification (LOQ), linearity, recovery, and precision. The highest results of LOD and LOQ were found for Ca, K, Na, Mg, and S. The recovery percentages are in the range from 71.01 to 117.31% in tropical fruits. The digestion efficiency was correlated with the residual carbon content, which was determined by total organic carbon analyzer (TOC). Six milliliters of HNO3 + 2 mL of HCl digestion method was chosen as the effective digestion method because of the lowest residual carbon contents and the accuracy results.

Assessment of quality test methods for solid recovered fuel in South Korea

Management of solid recovered fuel (SRF) in South Korea is unique from most other countries in that it is based on a single standard. All SRFs are distributed at the same price irrespective of their performance, resulting in utilization problems and a low degree of acceptance among consumers. Moreover, the difficulty of temperature maintenance during transportation, excessive ash content, and the use of inappropriate microwave acid digestion methods pose challenges to SRF reliability. To address these issues, we compared the relevant management statuses in South Korea with those of the international community and reviewed the effects of the transportation temperature, ash content, and microwave acid digestion technique. The moisture, ash, sulfur, and chlorine contents as well as the lower heating values (LHVs) of all the samples from South Korea were found to be below the standard [international] thresholds, and they were barely influenced by the transportation temperature. In addition, 5 g samples were found to be more appropriate for ash content analysis than the 20 g samples used in South Korea, with the former producing smaller standard deviations. The optimal microwave acid digestion conditions were also determined to be a reaction time with nitric acid of >10 min, temperature of 180 °C, and microwave power of 600 W. The results of this study highlight the need for revising the SRF test methods used in South Korea, to boost the market and enhance quality reliability.

Application of high-resolution 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry in rhenium determination

The possibilities of 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry equipped with a high-resolution spectrometer (spectral bandwidth = 5 pm) (HR-ICP-OES) were studied in the determination of rhenium in molybdenum and copper concentrates. By using equipment with a high spectral resolution, a hyperfine structure (HFS) of the most prominent lines of rhenium (i.e., Re II 197.248 nm, Re II 221.426 nm and Re II 227.525 nm) were registered. The HFS components, under high-resolution conditions, were used as separate prominent lines in order to circumvent spectral interferences in the presence of complex matrix containing Mo, Al, Ti, Fe, Mg, Ca and Cu. The Q-concept was applied for quantification of the spectral interferences and optimum line selection. Microwave acid digestion method was used as a sample dissolution procedure. The feasibility, accuracy and precision of the analytical results were experimentally demonstrated by certified reference materials from molybdenum and copper concentrates. Comparative data for true detection limits by using HR-ICP-OES 40.68 MHz ICP and Slurry sampling total reflection X-RAY fluorescence were presented in the determination of rhenium in CRM Molybdenum concentrate “CGL-202”.

Final report on CCQM-K89: Trace and essential elements in Herba Ecliptae

The key comparison CCQM-K89 was undertaken to demonstrate the capability of participating NMIs and DIs in measuring the contents of incurred trace elements (total arsenic, cadmium and lead) and essential elements (calcium and zinc) at µg/g (for arsenic, cadmium, lead and zinc) and mg/g (for calcium) levels in a herb matrix sample by various analytical techniques.This key comparison was organized by the Government Laboratory of the Hong Kong Special Administrative Region (GLHK) and agreed at the Inorganic Analysis Working Group Meeting in Hindås, Sweden in October 2010 as a benchmarking exercise with arsenic (a trace element) and calcium (an essential element) chosen as the 'exemplary' elements. It was also agreed that a pilot study CCQM-P126 would be run in parallel with this key comparison.The key comparison serves to facilitate claims by participants on the Calibration and Measurement Capabilities (CMCs) as listed in Appendix C of the Key Comparison Database (KCDB) under the Mutual Recognition Arrangement of the International Committee for Weights and Measures (CIPM MRA).A total of 20 NMIs/DIs registered for this programme and 18 of them submitted their results. Most of the participants used microwave acid digestion methods for sample dissolution. For the instrumental determination, a variety of techniques like ICP-MS, AAS, INAA, ICP-AES were employed by the participants. For this key comparison, inorganic core capabilities have been demonstrated by concerned participants with respect to methods including ICP-MS (without isotope dilution), ID-ICP-MS, ICP-AES, INAA, AAS and ion chromatography with iteratively matrix-matched calibration on the determination of total arsenic, calcium, cadmium, lead and zinc in a matrix of herb.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Final report on APMP.QM-S5: Essential and toxic elements in seafood

The supplementary comparison APMP.QM-S5 was undertaken to demonstrate the capability of participating national metrology institutes (NMIs) and designated institutes (DIs) in measuring the contents of the incurred essential elements (iron and zinc) and toxic elements (total arsenic and cadmium) at µg/g levels in a test sample of dried shrimp by various analytical techniques.At the APMP TCQM Meeting held in Pattaya, Thailand in November 2010, Government Laboratory of the Government of the Hong Kong Special Administrative Region (GLHK) proposed this APMP supplementary comparison. The proposal was further discussed and agreed upon at the CCQM Inorganic Analysis Working Group Meeting held in Paris in April 2011. GLHK was the coordinating laboratory for the supplementary comparison. For enhancing the collaboration amongst specialized regional bodies in Asia-Pacific and to help build the laboratory capacity of NMIs/DIs from developing economies, the reference values of the supplementary comparison are used for evaluation of performance of participants of an APMP proficiency testing programme (APMP PT 11-01), an Asia-Pacific Laboratory Accreditation Cooperation proficiency testing programme (APLAC T082) and an Asia-Pacific Economic Co-operation proficiency testing programme (APEC PT), which were concurrently run using the same testing material as in APMP.QM-S5.The supplementary comparison serves to facilitate claims by participants on the Calibration and Measurement Capabilities (CMCs) as listed in Appendix C of the Key Comparison Database (KCDB) under the Mutual Recognition Arrangement of the International Committee for Weights and Measures (CIPM MRA).A total of 18 institutes registered for the supplementary comparison and all of them submitted their results. Most of the participants used microwave acid digestion methods for sample dissolution. For the instrumental determination, a variety of techniques like ICP-MS, ICP-OES, INAA and AAS were employed by the participants. For this supplementary comparison, inorganic core capabilities have been demonstrated by concerned participants with respect to methods including ICP-MS (without isotope dilution), ID-ICP-MS, ICP-OES, INAA and AAS on the determination of total arsenic, cadmium, iron and zinc in a matrix of seafood.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the APMP, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

플라스틱 소재의 비소 함유량 분석에 관한 연구

연속흐름 수소화물 생성-유도결합 플라스마 원자 방출 분광기(FI-HG-ICP-AES) 이용하여 플라스틱 소재에 함유된 비소를 정량하기 위한 조건을 얻었다. 플라스틱 시료를 습식 산 분해 방법 및 마이크로파 산 분해 방법으로 전처리하여 시험 용액을 조제하였다. 인증표준물질(CRM)인 CRM-EC680k 및 CRM-EC681k를 사용하여 측정한 값과 인증값을 비교하여 분석 방법의 재현성 및 정확성을 확인하였다. 습식 산 분해 방법 및 마이크로파 산 분해 방법으로 전처리하여 FI-HG-ICP-AES로 측정한 결과 CRM-EC680k의 경우에는 4.1~4.3 mg/kg (인증값 <TEX>$4.1{\pm}0.5$</TEX> mg/kg)이고, CRM-EC681k의 경우에는 28.9~30.6 mg/kg (인증값 <TEX>$29.1{\pm}1.8$</TEX> mg/kg)이었다. Quantitative analytical condition for arsenic in plastic materials by the flow injection-hydride generation-inductively coupled plasma-atomic emission spectrometry was studied. The plastic samples were dissolved by wet-acid digestion method and microwave-acid digestion method. The reproducibility and accuracy in this method was verified using of certified reference materials(CRMs) CRM-EC680k and CRM-EC681k. The analyical results agrees with certified value within the range of uncertainty. The results of CRM-EC680k wer 4.1~4.3 mg/kg (certified value <TEX>$4.1{\pm}0.5$</TEX> mg/kg), and the results of CRM-EC681k were 28.9~30.6 mg/kg (certified value <TEX>$29.1{\pm}1.8$</TEX> mg/kg).

Seasonal Variations of Heavy Metals Concentration in Abattoir Dumping Site Soil in Nigeria

Assessment of seasonal variation in concentration of the heavy metals- Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn- in Abattoir dump site soil at Yauri, Nigeria, was undertaking during the two major seasons of Nigeria. Thiswas done to determine the environmental pollution status of the soil at the dump site. Soil samples (0–15cm) collected during the 2007/2008 rainy and dry seasons were treated and digested using microwave acid digestion methods. The heavy metal concentrations were determined with Atomic Absorption spectrophotometer (AAS). Themean levels range of Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were 13.2 - 30.02mg/kg, 59.14–102.50mg/kg, 59.32 –96.13mg/kg, 2569 – 4130mgkg, 263.01 – 608.11mg/Kg, 36.21 –107.13mg/kg, 15.60 – 30.09mg/kg and56.31–92.50mg/kg for dry seasons and 10.13–22.76mg/kg,49.96– 89.46mg/kg,49.12–73.08mg/kg,23330.02– 3671.14mg/kg,249.72– 61.03mg/kg,33.50–99.06mg/kg,16.20–28.11mg/kg, and 50.91- 89.10mg/kg for wet seasonrespectively. The analytical results indicated that in both wet and dry seasons some metals concentrations were above the literature levels of a typical soil, which course for concern.

Analysis of heavy metals concentration in road sides soil in Yauri, Nigeria

Assessment of seasonal variation in physiochemical properties and concentration of the heavy metals in road side soil in Yauri, was undertaking during the two major seasons of Nigeria. This was done to determine the environmental pollution status of the soil at the road side. Soil samples collected during the 2007/2008 rainy and dry seasons were treated and digested using microwave acid digestion methods. The heavy metal concentrations were determined with Atomic Absorption spectrophotometer. The mean levels range of As, Cd, Cr, Cu, Fe, Ni, Pb and Zn were 1.15 - 3.14, 0.14 - 7.0,1.64 - 22.36, 4.86 - 29.30, 2001 - 8091, 351.6 - 843.3, 35.9 - 306.7, and 79.6 - 202.4 µg/g for dry season and ND – 13.04 µg/g, ND - 7.02, ND - 13.79, 0.99 - 23.72, 748 - 6000, 201.13 - 507.10, 24.00 - 316.14 and 33.84 - 131.06 µg/g for wet season respectively. When metals concentrations in the soil of dry and wet seasons were correlated (p < 0.05) it was revealed that there were strong correlations between all the metals with the exception of Ni. Generally, higher mean heavy metal concentrations were recorded in the soil during the dry season than in wet season. The analytical results indicated that in both wet and dry seasons most of the heavy metals were above the natural heavy metals concentrations of surface soil which course for concern as these metals can accumulate to pollute the environment. Key words: Pollution, heavy metals, Yauri, concentration.

A New Microwave Acid Digestion Bomb Method for the Determination of Total Fluorine

A new microwave acid digestion method for total fluorine analysis was compared to the reliable reverse-extraction technique. The commercially available Parr bombs which are compatible with microwave heating were modified for this purpose. The Mann-Whitney statistical test did not show any significant differences (p > 0.05) in the determinations of total fluorine in various samples between the two above-mentioned methods. The microwave method also gave high fluorine recoveries (> 97%) when fluoride was added to different samples. The great advantage of the microwave acid digestion bomb method is that the digestion under pressure is so aggressive that only a few minutes is needed for complete digestion (also of covalently bonded fluorine), which reduces the time for fluorine analysis dramatically, while no loss of fluorine or contamination from extraneous sources could take place during the ashing procedure. The digestion solution was made up of 300 μl of concentrated nitric acid plus 537 μl of water. After digestion 675 μl of ∼ 8.5 M sodium hydroxide plus 643 μl of citrate/TISAB buffer was added resulting in an alkaline solution (pH ∼ 12) which was finally adjusted to a pH of ∼ 5.3 for fluoride determination.

210Pb and210Po analysis in sediments and soils by microwave acid digestion

A microwave acid digestion method prior to the determination of210Pb and210Po in sediments and soils is described. It involves an acid (HNO3, HCl, HF and H3BO3 mixture) digestion with microwave heating in closed vessels at high pressures. Analyses carried out for various reference materials showed that the results were statistically equal to certified values and reproducibility was also assured. The advantage of the microwave technique compared to the traditional leaching procedures is that the solid materials are completely dissolved and, therefore, ca. 100% efficiency is achieved in the extraction of210Po and210Pb, even though a fraction is associated to the silica net. Moreover, time of analysis is drastically reduced, as are the risks associated to vapour inhalation and material corrosion.

Application of the microwave acid digestion method to the decomposition of rock samples

The microwave acid digestion method was applied to the decomposition of rock samples and optimum conditions were investigated. Samples of 10–100 mg were decomposed by changing the amount and composition of acid, heating time and number of reheating steps and then the concentrations of Si, Fe, Mn, Na, K and Mg in these samples were measured. The concentrations agreed with reported values when 10 mg of sample were decomposed by heating for 60 s with 0.3 ml of concentrated HNO 3 and 0.1 ml of concentrated HF. Similarly, 100 mg of sample were also decomposed successfully by heating for 45–110 s with 0.3–1.0 ml of concentrated HNO 3 and 0.4–0.7 ml of concentrated HF. It is concluded that the microwave acid digestion method decomposes rock samples with a very short heating time and with small amount of reagents compared with methods using conventional sealed PTFE vessels, which require several hours for the heating step and several millilitres of reagents.

Applicability of microwave acid digestion to sample preparation of biological materials for analysis by particle-induced X-ray emission (PIXE)

A microwave acid digestion method for the preparation of biological samples for PIXE analysis is presented. The precision and accuracy of the entire PIXE analytical procedure, including the microwave digestion step, were evaluated by analyzing eight certified reference materials. For elements heavier than K, and for concentration levels from 2 micrograms/g upward, the total random error of a single analysis is in the range of 2-5%. The accuracy is better than 5%. The detection limits are down to 0.3 micrograms/g.

Rapid hydrolysis of proteins and peptides by means of microwave technology and its application to amino acid analysis.

A rapid heating method of hydrolysis by the use of microwave oven has been applied to amino acid analysis of proteins and peptides. This convenient method has been compared with the conventional 6 N HCl hydrolysis at 110 degrees for 24 h. The advantages of this new method are its expedition and the accurate and comparable results as compared to the tedious conventional technique. The method provides a rapid processing of multiple samples within minutes instead of days and inexpensive access to the important data of amino acid compositions of proteins by the commonly used microwave oven. The necessary change in the design of hydrolysis vials and the safety precautions accompanying this novel use of microwave acid-digestion method are also described.