微波消解-火焰原子吸收光谱法测定中药女贞子中9种金属元素

用微波消解法处理样品,用硝酸-过氧化氢(4+1)混合溶液作为消解剂进行微波消解,火焰原子吸收光谱法测定了中药女贞子中钙、镁、钾、钠、铁、锶、锰、铜和锌元素含量。9种元素检出限(3S/N)在0.000 6~0.024 8 mg.L-1之间,回收率在93.0%~107.3%之间,相对标准偏差(n=10)在0.86%~4.39%之间。试验结果表明:女贞子中钾、钙、镁、铁、钠、锌、锰、铜和锶质量分数分别为16 940,1 790,1 640,467.8,116.0,24.5,15.0,9.6,1.9μg.g-1,锌与铜含量的比值为2.55。由此可见,女贞子中钙、镁、钾元素含量丰富,铁含量也较高。为探讨中药金属元素种类及含量与治疗心血管疾病的关系等提供有用数据。     

Determination of Five Elements in Rose leaves by Microwave Digestion — FAAS

用微波消解-火焰原子吸收光谱法测定了玫瑰枝条和叶片中5种微量元素元素(钙、铜、铁、锰、镁)的含量.结果表明,玫瑰枝条和叶片中含有较丰富的镁、钙、铁,铜、锰含量较低,该法灵敏度高、快速、准确,所测数据可为玫瑰枝叶的合理利用提供可靠依据.     

微波消解样品-火焰原子吸收光谱法测定小叶黄杨木中金属元素

采用微波法消解样品,用火焰原子吸收光谱法分别测定了小叶黄杨木不同部位的钙、镁、铁、铜、锌、锰和钴含量,以及该植物对不同金属元素吸收情况.7种金属元素的线性回归方程的相关系数在0.996～0.999之间,各元素平均加标回收率在94.0%～109.5%范围,相对标准偏差(n=5)为2.1%～6.6%.     

微波消解-电感耦合等离子体发射光谱法测定固体生物质燃料中8种元素

建立电感耦合等离子体发射光谱法同时测定固体生物质燃料中钾、钠、钙、镁、砷、铜、铁、锰8种元素的含量。样品采用5 mL硝酸溶液和2 mL过氧化氢溶液进行微波消解,在选定的仪器工作条件下进行测定。钠、钙、镁、砷、铜、铁、锰的质量浓度在0～5.0 mg/L,钾的质量浓度在0～50.0 mg/L范围内与光谱强度具有良好的线性关系,相关系数均大于0.999,方法检出限为0.002～0.022 mg/L。样品的加标回收率为91.9%～108.2%,测定结果的相对标准偏差为2.1%～6.8%(n=6)。该方法简便、快速、高效且准确,适用于固体生物质燃料中钾、钠、钙、镁、砷、铜、铁、锰的测定。     

电感耦合等离子体原子发射光谱法测定枸杞中11种元素含量

采用电感耦合等离子体原子发射光谱法测定了枸杞中锌、铅、锰、铁、铬、镁、钙、铜、钠、钾和镉11种元素含量。选择硝酸(2+98)溶液作为介质,选择波长为213.86,220.35,257.61,259.94,267.72,279.08,324.75,317.93,589.59,766.49,226.50 nm 11条谱线依次作为测定锌、铅、锰、铁、铬、镁、钙、铜、钠、钾和镉的分析线,测得11种元素的检出限(3δ)均低于0.07 mg·L~(-1),相对标准偏差(n=11)在0.72%～2.40%之间。比较了常规湿法消化法、高压消化罐法和微波消解法处理样品对测定结果的影响。研究表明,高压消化罐法和微波消解处理样品精密度好。     

微波消解-原子吸收光谱法测定粮谷中铅、铜、镉、镁、锰、铁

用微波消解法进行样品消解,原子吸收光谱法测定了小麦粉国家标准物质中铅、铜、镉、镁、锰、铁6种元素的含量.其中镁、锰、铁用火焰原子化法,铅、铜、镉用石墨炉原子化法,方法的相对标准偏差分别为1.43%(镁),4.72%(镉),5.20%(锰),6.04%(铜),13.8%(铁)及18.7%(铅),检出限分别为0.001(铅及铜),0.000 1(镉),0.01(锰)及O.02(镁和CA)mg·kg-1.     

微波消解-火焰原子吸收法测定玫瑰枝叶的5种微量元素

用微波消解一火焰原子吸收光谱法测定了玫瑰枝条和叶片中5种微量元素元素（钙、铜、铁、锰、镁）的含量。结果表明,玫瑰枝条和叶片中含有较丰富的镁、钙、铁,铜、锰含量较低,该法灵敏度高、快速、准确,所测数据可为玫瑰枝叶的合理利用提供可靠依据。     

火焰原子吸收光谱法测定感冒灵颗粒中的金属元素含量

目的建立感冒灵颗粒中6种金属元素的火焰原子吸收测定方法。方法采用微波消解样品,利用火焰原子吸收光谱法测定感冒灵颗粒中钙、镁、铁、锌、铜和锰含量。结果该测定方法的回收率在95.11%~106.23%之间,市售感冒灵颗粒中含有一定的金属元素,锰和钙含量较高。结论该法简便、准确,结果令人满意。     

微波消解——FAAS测定康定鼠尾草中8种元素的含量

用微波消解-火焰原子吸收光谱法测定了康定鼠尾草药材中8种元素(钙、铜、铁、锰、锌、镁、铅、镉)的含量。结果表明,康定鼠尾草药材中含有较丰富的镁、钙、铁,该法灵敏度高、快速、准确,所测数据可为康定鼠尾草药材的合理利用提供可靠依据。     

微波消解ICP-OES法快速测定雪莲果中的微量元素

微波消解雪莲果样品后,等离子体发射光谱仪一次进样曝光快速测定了钾、钠、钙、镁、铜、铁、锌、锰、钼、镍10种微量元素。结果表明,雪莲果中富含钾、钙、镁等元素。该法一次消解样品、多元素同时测定,准确、快速、精密度高,符合分析要求。     

Evaluation of microwave-assisted digestion condition for the determination of metals in fish samples by inductively coupled plasma mass spectrometry using experimental designs

This paper describes the development of a compromised single-stage microwave-assisted digestion condition for multi-element determination in fish samples by inductively coupled plasm: mass spectrometry using experimental designs. A Plackett–Burman design was carried out as a multivariate strategy to investigate the main effects of the following parameter on microwave-assisted nitric acid digestion: microwave irradiation time, ramp time, digestion temperature, microwave power limit and the addition of hydrogen peroxide or hydrochloric acid. The most significant microwave setting parameters (radiation time, ramp and temperature) were further evaluated by response surface methodology under Box–Behnken design, while others were kept constant. The influences of different parameters vary according to metal element, thus the working conditions were established as a compromise within optimum region found for each targeted element which ensures quantitative recoveries and time efficiency. The compromised conditions are: ramp to 185°C in 10.5?min then hold for 14.5?min with 1600W (50%) of microwave power, using reagent mixture composed of 2.5?mL nitric acid, 0.5?mL hydrochloric acid and 7.0?mL water. Good agreements were demonstrated between measured and certified values with respect to DORM-3, DOLT-4 and ECM-CE278 and this method was successfully applied for metals determination in tilapia tissues.     

微波消解-微波等离子体炬原子发射光谱测定啤酒中的铜、锌、铁、锰、硒、锶

建立了微波消解-微波等离子体炬原子发射光谱(MPT-AES)法测定啤酒中微量元素。考察了微波前向功率、工作气流量、载气流量等参数,确定了MPT-AES法测定各元素的最佳实验条件。在该条件下铜、锌、铁、锰、硒、锶的检出限分别为7ng.mL-1、46ng.mL-1、13ng.mL-1、8ng.mL-1、1.2ng.mL-1、5.6ng.mL-1。相对标准偏差(RSD)均在0.9%～4.8%之间,线性范围分别为0.1～100μg.mL-1、0.5～100μg.mL-1、0.5～100μg.mL-1、0.1～100μg.mL-1、0.01～10μg.mL-1、0.05～100μg.mL-1,加标回收率均在96%～110%之间。     

Microwave heated vapor-phase digestion method for biological sample materials

A microwave heated, vapor-phase nitric acid-hydrogen peroxide digestion method for pulverized, biological sample materials was developed. Sample masses up to 200 mg were digested using calibrated quartz inserts inside first generation type, low-pressure, Teflon-PFA microwave vessels. In the first step, samples were digested in the vapor-phase for 80 min using a progressive heating pattern. Three mL of 70% nitric acid and 0.5 mL of 30% hydrogen peroxide were used as digestion reagents. In the second step, the small residue left after first step digestion was dissolved in 1.4% nitric acid or additionally with 0.5% hydrofluoric acid by heating for 15 min. The digestion method was optimized using pike (Esox lucius) muscle as a test material. The method was further optimized using three certified reference materials. Ca, Cu, Fe, Mg and Zn were determined from NIST-SRM 1577a bovine liver by ICP-AES. Cr and Ni were determined from NIST-SRM 8433 corn bran and NRCC DOLT-2 dogfish liver by GFAAS. For all elements the values obtained were close or within certified limits. Spike recoveries were between 96 to 107%. Digestion efficiency ranged from 91 to 99%.     

Microwave heated vapor-phase digestion method for biological sample materials

A microwave heated, vapor-phase nitric acid-hydrogen peroxide digestion method for pulverized, biological sample materials was developed. Sample masses up to 200 mg were digested using calibrated quartz inserts inside first generation type, low-pressure, Teflon-PFA microwave vessels. In the first step, samples were digested in the vapor-phase for 80 min using a progressive heating pattern. Three mL of 70% nitric acid and 0.5 mL of 30% hydrogen peroxide were used as digestion reagents. In the second step, the small residue left after first step digestion was dissolved in 1.4% nitric acid or additionally with 0.5% hydrofluoric acid by heating for 15 min. The digestion method was optimized using pike (Esox lucius) muscle as a test material. The method was further optimized using three certified reference materials. Ca, Cu, Fe, Mg and ¶Zn were determined from NIST-SRM 1577a bovine liver by ICP-AES. Cr and Ni were determined from NIST-SRM 8433 corn bran and NRCC DOLT-2 dogfish liver by GFAAS. For all elements the values obtained were close or within certified limits. Spike recoveries were between 96 to 107%. Digestion efficiency ranged from 91 to 99%.     

Investigation of microwave assisted drying of samples and evaporation of aqueous solutions in trace element analysis

Investigations of microwave assisted drying of sample materials and microwave assisted evaporation of aqueous sample solutions and acidic digestion residues were accomplished by means of special rotors for the microwave digestion system MULTIWAVE. To check the results obtained by microwave assisted drying, the samples were also conventionally dried at 105 degrees C in an oven. The following samples have been dried: 10 g each of meat, fish, apple, cucumber, potato, mustard, yogurt, clay and marl; 1 g each of certified reference material TORT 2 (lobster hepatopancreas), BCR 278 (mussel tissue) and BCR 422 (cod muscle); 500 g garden mould. Microwave assisted drying takes 40 min for organic samples and 30 min for inorganic material. Important is a slow increase of microwave power during the first 20 min. The results agree well with conventional drying at 105 degrees C. Losses of As, Se and Hg have been investigated for 3 CRMs. Only Se shows losses in the range of 20%. Losses of As, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, Tl, V and Zn after evaporation of aqueous samples and acidic solutions after wet digestion, respectively, have been investigated. 50 mL aqueous solution was evaporated almost to dryness within 25 min. The recovery of Hg is 40-50%, of Se 90-95% and of the other elements 97-102%. 0.2 g each of TORT 2, BCR 278 and BCR 422 have been digested with 4 mL nitric acid and 1 mL hydrochloric acid by means of the microwave digestion system MULTIWAVE. The digestion residue was evaporated almost to dryness and dissolved again in 10 mL diluted nitric acid. In this case no element losses have been observed. The measured concentration of As, Cd, Cu, Fe, Mn, Hg, Pb, Mo, Ni, Se, Sr, V and Zn agree very well with the certified values. An important prerequisite for good recoveries is not to evaporate the solutions to complete dryness.     

Pressure‐assisted tryptic digestion using a syringe

A simple and effective digestion method was developed using a syringe. A 3 mL syringe was used to apply a pressure of 6 atm to expedite tryptic digestion. Application of a pressure of 6 atm during digestion resulted in better digestion efficiency than digestion under atmospheric pressure. The protein peaks in the matrix‐assisted laser desorption/ionization mass spectra of three model proteins (cytochrome c, horse heart myoglobin, and bovine serum albumin (BSA)) completely disappeared within 30 min at 37°C under a pressure of 6 atm, with greater numbers of peptides observed in 30 min pressure‐assisted digestion than in overnight atmospheric pressure digestion. This is mostly due to the miscleaved peptides. Similar sequence coverages were obtained for 30 min pressure‐assisted digestion and overnight atmospheric pressure digestion of the three model proteins (92% vs. 88% for cytochrome c, 100% vs. 97% for horse heart myoglobin, and 53% vs. 53% for BSA). Copyright © 2010 John Wiley & Sons, Ltd.     

Investigation of microwave assisted drying of samples and evaporation of aqueous solutions in trace element analysis

Investigations of microwave assisted drying of sample materials and microwave assisted evaporation of aqueous sample solutions and acidic digestion residues were accomplished by means of special rotors for the microwave digestion system MULTIWAVE. To check the results obtained by microwave assisted drying, the samples were also conventionally dried at 105?°C in an oven. The following samples have been dried: 10 g each of meat, fish, apple, cucumber, potato, mustard, yogurt, clay and marl; 1 g each of certified reference material TORT 2 (lobster hepatopancreas), BCR 278 (mussel tissue) and BCR 422 (cod muscle); 500 g garden mould. Microwave assisted drying takes 40 min for organic samples and ¶30 min for inorganic material. Important is a slow increase of microwave power during the first 20 min. The results agree well with conventional drying at 105?°C. Losses of As, Se and Hg have been investigated for ¶3 CRMs. Only Se shows losses in the range of 20%. Losses of As, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, Tl, V and Zn after evaporation of aqueous samples and acidic solutions after wet digestion, respectively, have been investigated. 50 mL aqueous solution was evaporated almost to dryness within 25 min. The recovery of Hg is 40–50%, of Se 90–95% and of the other elements 97–102%. 0.2 g each of TORT 2, BCR 278 and BCR 422 have been digested with 4 mL nitric acid and 1 mL hydrochloric acid by means of the microwave digestion system MULTIWAVE. The digestion residue was evaporated almost to dryness and dissolved again in 10 mL diluted nitric acid. In this case no element losses have been observed. The measured concentration of As, Cd, Cu, Fe, Mn, Hg, Pb, Mo, Ni, Se, Sr, V and Zn agree very well with the certified values. An important prerequisite for good recoveries is not to evaporate the solutions to complete dryness.     

Use of microwave digestion and atomic absorption spectrophotometry to determine chromic oxide as a digestibility marker in feed, feces, and ileal content.

Most conventional digestion procedures, such as dry ashing and wet ashing, are tedious and labor intensive. Microwave digestion is a good alternative, because microwave dissolution is faster, safer, and simpler, and provides more controlled reproducible conditions than conventional methods. The purpose of this study was to develop a microwave digestion method for mineralizing meat and bone meal diets, feces, and ileal contents. Each sample was heated on a hot plate for 10 min, dry ashed at 65 degrees C for 4 h, and transferred into microwave vessels. Then, 10 mL 70% HNO3 was added. Samples were digested for 7, 10, and 20 min at 95, 90, and 85% power, respectively. After the heating cycle, 6 mL 30% H2O2 was added, and samples were returned to the microwave for a second heating cycle of 1 and 7 min at 95% and 90% power, respectively. Finally, chromium concentration was determined by flame atomic absorption spectrophotometry. The digestion method was validated by using a standard reference material, SRM domestic sludge 2781, with a certified chromium value of 195 +/- 9 micrograms/g. The value obtained in this study was 178 +/- 11 micrograms/g, for a difference of 17 micrograms/g. Spike recovery experiments resulted in 103.16 and 100.35% recoveries of chromium from diet and feces samples, respectively. Coefficients of variation were 10.8 and 7.8%, respectively.     

Microwave digestion of "residual fuel oil" (NIST SRM 1634b) for the determination of trace elements by inductively coupled plasma-mass spectrometry

A microwave procedure for the digestion of the NIST 1634b reference material "residual fuel oil" in closed pressurized vessels was developed in an attempt to facilitate routine analysis and obtain reproducible conditions or comparable results. The influence of sample size, reagent composition and volume, microwave power, and duration of heating on the digestion procedure was studied. Pressure and temperature inside the reaction vessels were monitored to determine the progression of the reaction and to develop optimal conditions. A nine-step heating program requiring 36.5 min with microwave power not exceeding 450 W in the pulsed mode was found suitable for the digestion of approximately 250 mg fuel oil with a mixture of nitric acid (5.0 mL) and hydrogen peroxide (2.0 mL). The reproducibility of microwave power was determined in terms of the relative standard deviations (n = 3) for temperature (2.7%) and pressure (4.9%) data. The vapor pressures obtained with 5.0 mL Milli-Q water (heated) in an 80-mL digestion vessel showed good agreement with literature data. The excess acid in the resulting digests was removed by evaporation and the concentrations of 24 elements (Ag, Al, As, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mo, Ni, Pb, Sb, Sn, Sr, Ti, Tl, V, U, and Zn) were determined in the diluted digests by inductively coupled plasma mass spectrometry (ICP-MS). The experimental results were in good agreement with the certified and recommended concentrations for eight elements (Al, As, Co, Cr, Ni, Pb, V, Zn) in solutions obtained after one digestion step. An additional digestion step, consisting of intermediate cooling and venting stages, was required for the accurate determination of Fe. No agreement was reached for Ca and Ba even after two-step digestion. The proposed method of digestion provided precise results with relative standard deviations generally less than 5% for most of the elements determined.     

Microwave digestion of “residual fuel oil” (NIST SRM 1634b) for the determination of trace elements by inductively coupled plasma-mass spectrometry

A microwave procedure for the digestion of the NIST 1634b reference material “residual fuel oil” in closed pressurized vessels was developed in an attempt to facilitate routine analysis and obtain reproducible conditions or comparable results. The influence of sample size, reagent composition and volume, microwave power, and duration of heating on the digestion procedure was studied. Pressure and temperature inside the reaction vessels were monitored to determine the progression of the reaction and to develop optimal conditions. A nine-step heating program requiring 36.5 min with microwave power not exceeding 450 W in the pulsed mode was found suitable for the digestion of ～ 250 mg fuel oil with a mixture of nitric acid (5.0 mL) and hydrogen peroxide (2.0 mL). The reproducibility of microwave power was determined in terms of the relative standard deviations (n = 3) for temperature (2.7%) and pressure (4.9%) data. The vapor pressures obtained with 5.0 mL Milli-Q water (heated) in an 80-mL digestion vessel showed good agreement with literature data. The excess acid in the resulting digests was removed by evaporation and the concentrations of 24 elements (Ag, Al, As, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mo, Ni, Pb, Sb, Sn, Sr, Ti, Tl, V, U, and Zn) were determined in the diluted digests by inductively coupled plasma mass spectrometry (ICP-MS). The experimental results were in good agreement with the certified and recommended concentrations for eight elements (Al, As, Co, Cr, Ni, Pb, V, Zn) in solutions obtained after one digestion step. An additional digestion step, consisting of intermediate cooling and venting stages, was required for the accurate determination of Fe. No agreement was reached for Ca and Ba even after two-step digestion. The proposed method of digestion provided precise results with relative standard deviations generally less than 5% for most of the elements determined.