Simultaneous determination of suspended particulate trace metals (Co, Ni, Cu, Zn, Cd and Pb) in seawater with small volume filtration assisted by microwave digestion and flow injection inductively coupled plasma mass spectrometer

A new technique for the determination of suspended particulate trace metals (P-metals >0.2 μm), such as Co, Ni, Cu, Zn, Cd and Pb, in open ocean seawater has been developed by using microwave digestion coupled with flow injection inductively coupled plasma mass spectrometry (FI-ICP-MS). Suspended particulate matter (SPM) was collected from 500 mL of seawater on a Nuclepore filter (0.2 μm) using a closed filtration system. Both the SPM and filter were completely dissolved by microwave digestion. Reagents for the digestion were evaporated using a clean evaporation system, and the metals were redissolved in 0.8 M HNO₃. The solution was diluted with buffer solution to give pH 5.0 and the metals were determined by FI-ICP-MS using a chelating adsorbent of 8-hydroxyquinoline immobilized on fluorinated metal alkoxide glass (MAF-8HQ). The procedure blanks with a filter were found to be 0.048 ± 0.008, 10.3 ± 0.3, 0.27 ± 0.05, 3.3 ± 1.8, 0.02 ± 0.03 and 0.85 ± 0.09 ng L⁻¹ for Co, Ni, Cu, Zn, Cd and Pb, respectively (n = 14). Detection limits defined as 3 times the standard deviation of the blanks were 0.023, 0.90, 0.14, 5.3, 0.078 and 0.28 ng L⁻¹ for Co, Ni, Cu, Zn, Cd and Pb, respectively. Accuracy was evaluated using certified reference materials of chlorella (NES CRM No. 3) and marine sediment (HISS-1). The method was applied to the determination of vertical distributions for P-Co, Ni, Cu, Zn, Cd and Pb in the Western North Pacific.     

Comparison of slurry sampling and microwave-assisted digestion for calcium, magnesium, iron, copper and zinc determination in fish tissue samples by flame atomic absorption spectrometry

The development of a slurry sampling method for the determination of calcium, copper, iron, magnesium and zinc in fish tissue samples by flame atomic absorption spectrometry is described. In comparison with microwave-assisted digestion, the proposed method is simple, requires short time and eliminates total sample dissolution before analysis. Suspension medium was optimized for each analyte to obtain quantitative recoveries from fish tissue samples without matrix interferences. Nevertheless, iron recoveries higher than 46% were not found. Treatment of samples slurried in nitric acid by microwave irradiation for 15-30 s at 75-285 W permitted to achieve efficient recoveries for calcium, iron, magnesium and zinc. Further improvement in the matrix effects for iron determination was accomplished by the use of an additional step of short microwave-assisted suspension treatment. However, standard addition method was required for calcium and copper determination, being necessary hydrochloric acid as suspension medium for the last one. Although copper could not be determined in the certified reference material using microwave-assisted digestion, the accuracy of the slurry sampling method was verified for all the investigated analytes. Detection limits were 22.8 ± 8.0, 0.884 ± 0.092, 5.07 ± 0.76, 35.5 ± 0.7 and 1.17 ± 0.04 μg g⁻¹ for calcium, copper, iron, magnesium and zinc, respectively. The standard deviations obtained using slurry sampling method and microwave-assisted digestion were not significantly different, and the mean relative standard deviation of the over-all method (n = 3) of the slurry sampling method for different concentration levels was below 12%.     

Neutral persulfate digestion at sub-boiling temperature in an oven for total dissolved phosphorus determination in natural waters

A simplified, easily performed persulfate digestion method has been developed to process a large number of water samples for routine determination of total dissolved phosphorus. A neutral potassium persulfate solution (5%, w/v, pH ∼6.5) is added to the samples (at 10 mg potassium persulfate per mL of sample), which are then digested at 90 °C in an oven for 16 h. This method does not require pH adjustment after digestion because neither an acid nor a base is added to the samples prior to digestion. The full color of phosphoantimonylmolybdenum blue from the digested samples develops within 8 min. Compared with the autoclave method, digestion at sub-boiling temperatures in an oven is safer, and a large number of samples can be heated overnight requiring no constant monitoring. The apparent molar absorptivity (?) of nine organic phosphorus compounds and two condensed inorganic phosphates ranged from 1.17 × 10⁴ to 1.82 × 10⁴ L mol⁻¹ cm⁻¹ in both distilled water and artificial seawater matrixes. The average recovery of these phosphorus compounds was 94 ± 11% for the DIW matrix and 90 ± 12% for the ASW matrix. No significant difference in molar absorptivity was observed between the undigested and digested phosphate, especially in the seawater matrix. It is, therefore, suggested that a phosphate solution be directly employed without digestion as the calibration standard for routine determination of total dissolved phosphorus. This method was used to study the spatial distribution of total dissolved phosphorus in the surface waters of Florida Bay.     

Influence of microwave heating on fluoride, chloride, nitrate and sulfate concentrations in water

This paper describes a study about the influence of microwave radiation using closed vessels on fluoride, chloride, nitrate and sulfate concentrations in aqueous media. The experiments were processed by heating water using PFA vessels and a microwave cavity oven, determining the anions by ion chromatography. The influence of the exposure time, the atmospheric composition, the kind of heating (water bath or microwave radiation) and the possible formation of hydrogen peroxide were investigated. The limits of quantification for fluoride, chloride, nitrate and sulfate were respectively of 0.17, 0.15, 0.55 and 0.57 μg L⁻¹, and precision, expressed as RSD, was <4% for all considered anions. The hydrogen peroxide was quantified by spectrophotometry, and the limit of quantification and precision were 24 μg L⁻¹ and <5% (n = 10), respectively. The results demonstrate a significant increase in the anion concentration levels (between 63 and 89%) when microwave heating was used in comparison with heating by water bath. In addition, these changes observed can be mainly attributed to the species transfers, either between gaseous (atmospheric gases) and liquid (water) phases for nitrate, or between vessels walls and water for fluoride, chloride and sulfate. Additionally, hydrogen peroxide concentration higher than 45 μg L⁻¹ was determined when water was exposed to microwave radiation.     

Speciation analysis of mercury in seafood by using high-performance liquid chromatography on-line coupled with cold-vapor atomic fluorescence spectrometry via a post column microwave digestion

An automatic system, based on the on-line coupling of high-performance liquid chromatography (HPLC) separation, post column microwave digestion, and cold-vapor atomic fluorescence spectrometry (CVAFS) detection, was proposed for the speciation analysis of four mercury compounds. Post column microwave digestion, in the presence of potassium persulfate (in HCl), was applied in the system to improve the conversion efficiency of three organic mercury compounds into inorganic mercury. Parameters influencing the on-line digestion efficiency and the separation effect were optimized. To avoid water vapor and methanol entering into the atomic fluorescence detector, ice-water mixture bath was used to cool the microwave-digested sample solution. Four mercury species including inorganic mercury chloride (MC), methylmercury chloride (MMC), ethylmercury chloride (EMC) and phenylmercury chloride (PMC) were baseline separated within 13 min by using RP C₁₈ column with a mobile phase of 50% (v/v) methanol containing 10 mmol l⁻¹ tetrabutyl ammonium bromide and 0.1 mol l⁻¹ sodium chloride pumped at 1.2 ml min⁻¹. Seafood samples, composed of three gastropod species and two bivalve species from Yantai port, China, have been analyzed by the proposed method. Dogfish muscle (DORM-2) was analyzed to verify the accuracy of the method and the result was in good agreement with the certified value.     

Determination of total phosphorus in waters with amperometric detection by coupling of flow-injection analysis with continuous microwave oven digestion

For the determination of total phosphorus in waters by flow-injection analysis, a continuous microwave oven decomposition with subsequent amperometric detection of orthophosphate is proposed. The percentage digestion was examined for two different decomposition reagents and by varying the pH of the carrier and the length and diameter of the digestion coil. With potassium peroxodisulphate decomposition the recoveries of phosphorus vary from 91 to 100% for organic phosphorus compounds, and with perchloric acid decomposition the recoveries vary from 60 to 70% for inorganic polyphosphates. Calibration graphs are linear for up to 30 mg P l^?1, the determination limit is 0.1 mg P l^?1 and the precision of the method is 3% (relative standard deviation) (n = 5) at 5 mg P l^?1. The sampling rate is 20 h^?1. Good recoveries of phosphorus after addition to domestic waste water sample are obtained.     

Studying the effect of microwave heating on the digestion process and identification of proteins

The impact of microwave irradiation on the in‐solution digestion processes and the detection limit of proteins are systematically studied. Kinetic processes of many peptides produced through the trypsin digestion of various proteins under microwave heating at 50°C were investigated with MALDI‐MS. This study also examines the detection limits and digestion completeness of individual proteins under microwave heating at 50°C and at different time intervals (1, 5 and 30 min) using LC‐MS. We conclude that if the peptides without missed cleavage dictate the detection limit, conventional digestion will lead to a better detection limit. The detection limit may not differ between the microwave and conventional heating if the peptides with missed cleavage sites and strong intensity are formed at the very early stage (i.e., less than 1 min) and are not further digested throughout the entire digestion process. The digestion of Escherichia coli lysate was compared under conventional and short time (microwave) conditions. The number of proteins identified under conventional heating exceeded that obtained from microwave heating over heating periods less than 5 min. The overall results show that the microwave‐assisted digestion is not complete. Although the sequence coverage might be better, the detection limit might be worse than that under conventional heating.     

Single vessel procedure for acid vapor partial digestion of bovine liver in a focused microwave: multielement determination by ICP-OES

An acid vapor partial digestion procedure for bovine liver is proposed using a focused microwave oven and a laboratory-made PTFE support. The support is equipped with three cups of approximately 4 ml volume each one and the cups were adapted to the glass reaction vessel of the microwave oven. A mixture containing HNO₃ plus H₂SO₄ is heated to 120 °C to generate acid vapor. Bovine liver (50-90 mg) were directly weighed into the cups followed by addition of a mixture containing NaClO+H₂O₂. Samples were exposed to acid vapor during 15-25 min and then diluted with distilled and deionized water to final masses of 3.0 g. Recoveries of Al, Ca, Cu, Fe, Mg, Mn, and Zn were evaluated using an ICP-OES with axially-viewed configuration. The effects of both particle sizes and acid vapor exposure time were evaluated and recoveries of most elements were quantitative when using 25 min of heating and 50 mg of samples. Slightly better recoveries were reached using particles smaller than 44 μm, but this effect was mainly observed for hardly extracted elements such as Al and Fe.     

Microwave-assisted total digestion of sulphide ores for multi-element analysis

A new two-stage microwave-assisted digestion procedure using concentrated HNO₃, HCl, HF and H₃BO₃ has been developed for the chemical analysis of major and trace elements in sulphide ore samples prior to inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. In the first stage 0.2 g of the certified reference material (CRM) sample was digested with a combination of acids (HNO₃, HCl, and HF) in a closed Teflon vessel and heated in the microwave to 200 °C for 30 min. After cooling, H₃BO₃ was added and the vessel was reheated to 170 °C for 15 min. The precision of the method was checked by comparing the results against six certified reference materials. The analytical results obtained were in good agreement with the certified values, in most cases the recoveries were in the range 95-105%. Based on at least 17 replicates of sample preparation and analysis, the precision of the method was found to be ≤5%.     

Reaction kinetics of the microwave enhanced digestion of zircon with ammonium acid fluoride

Zircon is notorious for its chemical inertness. Extreme processing conditions such as alkaline fusion (NaOH at 600 °C or Na₂CO₃ at 1200 °C) are used to extract the zirconium values from the mineral. In this study zircon was treated with ammonium acid fluoride (NH₄F·1.5HF) by means of microwave assisted digestion. Reaction times ranged from 15 to 260 min at temperatures between 120 °C and 240 °C. Successive microwave digestion steps, interrupted by an aqueous wash procedure, resulted in a >99% conversion of zircon to the water soluble intermediates (NH₄)₃ZrF₇ and (NH₄)₂SiF₆. Arrhenius rate laws are derived for both reaction control (progressively shrinking particle) and diffusion control by the product layer. Both models show reasonably good agreement with the experimental data. The derived diffusion coefficient corresponds to a solid-liquid case.     

Microwave-assisted digestion of organoarsenic compounds for the determination of total arsenic in aqueous, biological, and sediment samples using flow injection hydride generation electrothermal atomic absorption spectrometry

A microwave assisted wet digestion method for organoarsenic compounds and subsequent determination of total arsenic in aqueous, biological and sediment samples by means of flow injection hydride generation electrothermal atomic absorption spectrometry (FI-HG-ETAAS) is described. Sodium persulfate, sodium fluoride and nitric acid serve as digestion reagents, which allow a quantitative transformation of organoarsenic compounds to hydride forming species in a commercial microwave sample preparation system. The maximum operating pressures of the applied tetrafluorometoxil (TFM) liners are 75 bar (high pressure vessels) and 30 bar (medium pressure vessels), corresponding to maximum solution temperatures of 300 and 260 °C. For the investigated samples, digestion temperatures of 210-230 °C (medium pressure vessels) and 240-280 °C (high pressure vessels) were obtained.In medium pressure vessels, arsenic recovery from aqueous testing solutions of dimethylarsinic acid (DMA), phenylarsonic acid (PAA) and tetraphenylarsonium chloride (TPA) at initial concentrations of 100 and 10 μg l⁻¹ is complete, even in the presence of an excess of organic carbon (potassium hydrogen phthalate, 2000 mg l⁻¹) or fatty acids (linolenic acid 70%; linoleic acid ≈20-25%; Oleic acid ≈3%, 900-4500 mg l⁻¹).Arsenic recovery from aqueous arsenobetaine (ASB) solutions with the same initial concentrations is also complete if high pressure vessels and a higher concentration of fluoride ions are used, whereas the addition of organic carbon (potassium hydrogen phthalate, 2000 mg l⁻¹, fatty acids, 900-4500 mg l⁻¹) leads to a decrease in arsenic recovery of about 2-5%. In all cases, residual carbon contents are close to the limit of detection for the applied analytical method (15 mg l⁻¹).Results of arsenic analysis in reference standard materials revealed a significant dependence on the material’s nature (sediment samples, plant materials and seafood samples). Sediment samples and plant materials show recoveries for arsenic around 100% after a single-step digestion in medium pressure TFM liners. Seafood (fish/lobster/mussel samples) usually require either the use of high pressure vessels or a second digestion step, if medium pressure vessels are used.     

微波消解-电感耦合等离子体发射光谱法测定植物样品中的磷、硫

本方法采用微波消解处理样品,电感耦合等离子体发射光谱法测定植物样品中的磷、硫的含量,选用优化微波消解条件进行消解,磷和硫方法最低检出限分别为0.925mg/kg、1.82 mg/kg。精密度RSD和相对误差RE均小于3%,对新鲜植物样品进行加标回收试验,加标回收率为90.5%~107%,证明本方法既可用于检测干植物样品,又可检测新鲜植物样品。     

Accelerated tryptic digestion for the analysis of biopharmaceutical monoclonal antibodies in plasma by liquid chromatography with tandem mass spectrometric detection

Accelerated tryptic digestion of a therapeutic protein including microwave irradiation and thermal transfer by convection at 60 °C and 37 °C was investigated. An analytical setup was devised to follow the protein digestion rate using 1D gel electrophoresis and liquid chromatography coupled a triple quadrupole linear ion trap mass spectrometer. The formation kinetic of its tryptic peptides was monitored in the selected monitoring mode (LC-SRM/MS). Different digestion end points (e.g. 2, 5, 10, 15, 30 and 60 min) as well as an overnight digestion were tested using a therapeutic human monoclonal antibody (mAb) with the goal of its LC-SRM/MS quantification in human plasma. The peptides from the human mAb were generated at different rates and were classified into three categories: (1) the fast forming peptides, (2) the slow forming peptides and (3) the peptides degrading over time. For many monitored peptides, a heating temperature of 37 °C with a 750 rpm mixing applied for at least 30 min provided equivalent results to microwave-assisted digestion and generally allowed the achievement of an equivalent peptide concentration as an overnight digestion carried out at 37 °C. The disappearance of the protein of the heavy and light chains can be monitored by 1D gel electrophoresis but was found not to be representative of the final tryptic peptide concentrations. For quantitative purposes a stable isotope labeled version (¹³C₄, ¹⁵N₁) of the therapeutic protein was used. The labeled protein as internal standard was found to be very efficient to compensate for incomplete digestion or losses during sample preparation.     

An ultrasound-assisted digestion method for the determination of toxic element concentrations in ash samples by inductively coupled plasma optical emission spectrometry

A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of toxic element concentrations (arsenic, barium, cobalt, copper, lead, nickel, strontium, vanadium and zinc) in ash samples was developed. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg(II) 280.270 nm/Mg(I) 285.213 nm line intensity ratios. The highest line intensity ratios were observed when a nebulizer gas flow of 0.6 L min⁻¹, auxiliary gas flow of 0.2 L min⁻¹ and plasma power of 1400 W were used for radially viewed plasma. The analysis of SRM 1633b showed that the ultrasound-assisted method developed is highly comparable with the microwave digestion method standardized by the United States Environmental Protection Agency (EPA-3052). The ultrasound-assisted digestion with a digestion solution of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 81%. One exception is arsenic which resulted in recoveries of about 60% only; however, it could be digested with good recovery (>90%) using a digestion solution of 5 mL of water and 5 mL of aqua regia. The major advantage of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (30 samples simultaneously with a sonication time of 18 min).     

Evaluation of an ultrasonic digestion procedure for total metal determination in sediment reference materials

In this work the possibility to use a simple and easily available laboratory device—routine ultrasonic bath—has been evaluated for total metal determination in sediments from different origin. The investigated instrumental parameters were time and temperature, whereas power was maintained constant set at 100% of nominal power. Four different sets of parameters were applied on a lake sediment reference material (RM), the results obtained for five elements—Cd, Cr, Cu, Ni and Zn—were statistically compared with those obtained by a previously optimised microwave acid digestion procedure on the same material. The optimal set of parameters—30 min sonication at ambient temperature—was chosen, and then applied to other five sediment RMs from different origin. In this case four additional elements—As, Pb, V and Fe—were also determined and the results were compared with reference and microwave values.The results obtained by the ultrasound digestion procedure were higher than 80% of the reference and/or microwave values in 40 out of 44 cases. In any case, the results obtained by ultrasonic procedure were statistically comparable to reference values (mean of means of interlaboratory exercises or certified values) in the 84% of the cases.     

Low volume microwave digestion and direct determination of selenium in biological samples by hydride generation-atomic fluorescence spectrometry

A low volume microwave digestion (LVMWD) procedure has been developed to have all forms of selenium (Se) compounds in biological samples decomposed to Se (IV) and allow total Se be directly determined by hydride generation-atomic fluorescence spectrometry (HG-AFS), or voltammetrically. Between 0.3 and 0.4 mL of mixed digestion reagents consisting of concentrated (15.4 M) HNO₃-(18.5 M) H₂SO₄ (v:v = 10:1) and >5 to <40 mg sample were found ideal systems with an optimized MW digestion program. Total Se in five certified reference materials was accurately determined. The results obtained by the conventional and LVMWD techniques agreed well. By avoiding pre-reduction step, this method, suitable for a wide range of biological samples, fully takes the advantages of HG-AFS or voltammetric techniques for their high sensitivity, high tolerance to matrix-related interference and accessibility in instrumentation. LVMWD not only enhances the sample output by 3 times and reduces the operational cost and acid wastes, but also makes the small sample analysis possible for many environmental and medical related research objectives. The digestion pathways of Se containing organic samples are also discussed based on the experimental results.     

Pressurized wet digestion in open vessels

The High Pressure Asher (HPA-S) was adapted with a Teflon liner for pressurized wet digestion in open vessels. The autoclave was partly filled with water containing 5% (vol/vol) hydrogen peroxide. The digestion vessels dipped partly into the water or were arranged on top of the water by means of a special rack made of titanium or PTFE-coated stainless steel. The HPA-S was closed and pressurized with nitrogen up to 100 bars. The maximum digestion temperature was 250 °C for PFA vessels and 270 °C for quartz vessels. Digestion vessels made of quartz or PFA-Teflon with volumes between 1.5 mL (auto sampler cups) and 50 mL were tested. The maximum sample amount for quartz vessels was 0.5–1.5 g and for PFA vessels 0.2–0.5 g, depending on the material. Higher sample intake may lead to fast reactions with losses of digestion solution. The samples were digested with 5 mL HNO₃ or with 2 mL HNO₃+6 mL H₂O+2 mL H₂O₂. The total digestion time was 90–120 min and 30 min for cooling down to room temperature. Auto sampler cups made of PFA were used as digestion vessels for GFAAS. Sample material (50 mg) was digested with 0.2 mL HNO₃+0.5 mL H₂O+0.2 mL H₂O₂. The analytical data of nine certified reference materials are also within the confidential intervals for volatile elements like mercury, selenium and arsenic. No cross contamination between the digestion vessels could be observed. Due to the high gas pressure, the diffusion rate of volatile species is low and losses of elements by volatilisation could be observed only with diluted nitric acid and vessels with large cross section. In addition, cocoa, walnuts, nicotinic acid, pumpkin seeds, lubrication oil, straw, polyethylene and coal were digested and the TOC values measured. The residual carbon content came to 0.2–10% depending on the sample matrix and amount.     

Multi-syringe flow injection system with in-line microwave digestion for the determination of phosphorus

A multi-syringe system for spectrophotometric determination of total phosphorus involving in-line digestion is proposed. Sample and digestion solution were dispensed and directed towards a digestion vessel located inside a domestic microwave oven (MWO) where sample digestion took place. Afterwards, the digested sample was merged with the necessary reagents for the colorimetric determination based on the molybdenum blue method. Several digestion conditions were studied regarding composition of digestion solution, digestion time and power set on the MWO. The system was applied to waste water samples and results shown a good agreement with the reference method. Repeatable results (R.S.D.<2.41%) and determination frequency of 12 h⁻¹ were obtained.     

Microwave-assisted alkaline digestion combined with microwave-assisted distillation for the determination of iodide and total iodine in edible seaweed by catalytic spectrophotometry

Microwave energy has been novelty applied to speed up a tetramethylammonium hydroxide (TMAH) alkaline digestion of seaweed samples and to assist distillation of iodine from seaweed alkaline digests. Iodide in the alkaline digests from seaweed and distilled iodine, reduced back to iodine in a hydroxylamine hydrochloride solution, was determined by a catalytic spectrophotometric method based on the catalytic effect of iodide on the oxidation of As(III) by Ce(IV) in H₂SO₄/HCl medium (Sandell-Kolthoff reaction). The determination of iodide was directly performed in the alkaline digests, while total iodine was assessed by analyzing the hydroxylamine hydrochloride solution after the distillation process. Microwave-assisted alkaline digestion was performed using 7.5 mL of TMAH and irradiating samples at 670 W for two 5.5 min steps. Microwave-assisted distillation was carried out using 4.0 mL of the alkaline digest and 3 mL of a 2.2 M hydrochloric acid and 0.05% (m/v) sodium nitrite solution, with a microwave power at 670 W for two 90 s steps. The distillate (iodine vapor) was bubbled in 10 mL of a 500 μg mL⁻¹ hydroxylamine hydrochloride solution (accepting solution). The linear calibration ranges were 0.30-20.0 and 0.40-20.0 μg L⁻¹ for iodide determination and total iodine determination, respectively. The limit of detection was 9.2 μg g⁻¹ for iodide and 28.5 μg g⁻¹ for total iodine. Repeatability of the overall procedures, expressed as R.S.D. for 11 determinations, was 2.6% for 196.3 μg g⁻¹ of iodide measured after microwave-assisted alkaline digestion, and 5.8% for 954.3 μg g⁻¹ of total iodine by microwave-assisted alkaline digestion followed by microwave-assisted distillation. Finally, accuracy of the methods was assessed by analyzing the NIST-09 (Sargasso) certified reference material and the methods were applied to the determination of iodide and total iodine in different Atlantic edible seaweed samples with satisfactory results.     

Evaluation of closed-vessel microwave digestion method for the determination of trace impurities in polymer-based photoresist by inductively coupled plasma mass spectrometry

A closed microwave digestion method followed by inductively coupled plasma spectrometric (ICP-MS) analysis was evaluated for the determination of trace impurities in photoresist. To optimize the digestion procedure, several digestion parameters such as acid, heating temperature and heating time were evaluated. Besides, the digestion efficiency of used photoresist material and the recovery of analyte elements obtained by the use of gravimetric method and ICP-MS measurement, individually, were also compared to clarify the completeness of digestion. According to our experiments, the gravimetric method was found to be not so relevant to the completeness of digestion, because the remaining sample matrix could cause suppression effect in the subsequent ICP-MS measurement. In view of minimizing blank value and working time, a simple single-step heating program was proposed to mineralize 0.25 ml of photoresist material with 5 ml of nitric acid at 180 °C for 10 min. Based on the comparative study of the analytical results obtained by instrumental neutron activation analysis (INAA) and proposed method, the reliability of proposed method for the determination of trace metallic impurities in photoresist material has been confirmed.