Rapid Microwave-assisted Extraction Research Articles

Rapid microwave-assisted extraction method for the analysis of common antidepressants and metabolites in marine organisms

Presence of antidepressants in aquatic environments could cause adverse effects even at low concentrations. Most published works have detected them in wastewater, and only a few have paid attention to the aquatic organisms that receive these polluted waters. This work presents the development, optimisation and application of an analytical method for the extraction and determination of four widely used antidepressants (venlafaxine, citalopram, sertraline, fluoxetine) and two metabolites (o-desmethylvenlafaxine, norsetraline) from fish tissue by microwave-assisted extraction and ultra high-performance liquid chromatography coupled to tandem mass spectrometry. To demonstrate the applicability of the method, it was validated in different marine organism species (fish, echinoderm, mollusc and algae). Under optimal conditions, recovery ranged between 70 and 120 % and deviation was lower than 20 % in most cases, depending on the species and the tested concentration. As no strong matrix effect was found, applying a clean-up step was unnecessary, although quantification was performed in real samples by matrix-matched calibration. Method quantification limits ranged between 2.32 and 196 ng g−1. Overall, this methodology proved to be a versatile method applicable to different species with good results. The developed analytical method was successfully applied to the extraction and determination of the target compounds from fish taken from offshore aquaculture cages in seawater (Canary Islands). Three main antidepressants were detected, but only two could be quantified: citalopram: 5.83 ng g−1 and sertraline: 6.58 ng g−1.

Efficient microwave-assisted extraction of salidroside from Rhodiola crenulata

A rapid microwave-assisted extraction (MAE) method was established to extract commercially important salidroside from dry plant materials of Rhodiola crenulata. Several parameters such as extraction time, solid/liquid ratio, extraction temperature and solvent concentration were investigated for efficient salidroside extraction. The estimated maximum salidroside extraction ratio based on parameter optimization using response surface methodology (RSM) reached 2.17% (w/w) in 20 min at optimum conditions of 90 °C, 60% aqueous ethanol and solid to liquid ratio of 2 g/100 mL, which was confirmed to the experimental data. Compared with ultrasonic assistant extraction method (UAE) and heat reflux extraction method (HRE), MAE was the most efficient and effective method in the extraction of salidroside from the dry plant materials. The mechanism on the extraction enhancement using MAE was elucidated further using fourier transform infrared spectroscopy (FTIR) and light microscope.

Microwave assisted extraction in combination with solid phase purification and switchable hydrophilicity solvent-based homogeneous liquid-liquid microextraction for the determination of sulfonamides in chicken meat

A rapid and eco-friendly method was developed to extract and pre-concentrate sulfonamides (sulfadiazine, sulfamerazine and sulfadimethoxine) from chicken meat before high-performance liquid chromatographic analysis. The method involved rapid microwave-assisted extraction with hydrochloric acid (pH = 5), further solid phase purification using HLB cartridge and 5% ammonium hydroxide, and homogeneous liquid-liquid microextraction using hexanoic acid as switchable hydrophilicity solvent. The overall time required for sample preparation was 10 min and the volume of organic solvent used for extraction was only 200 μL. The method exhibited good linearity (r2 > 0.9941), low limits of detection (2.5–6.0 ng/g) and allowed quantification of target sulfonamides spiked at levels of 50–400 ng/g in chicken meat with spiked recoveries in the range of 94.1%–112.0%.

Development of a simple and rapid microwave-assisted extraction method using very dilute solutions of perchloric acid and hydrogen peroxide for the multi-elemental analysis of food materials by ICP-OES: A green analytical method

A simple and rapid microwave-assisted extraction (MAE) method for the quantitative determination of various elements by inductively coupled plasma optical emission spectrometry (ICP-OES) has been developed. A single-step MAE procedure employing very dilute solutions of a mixture of HClO4 and H2O2 was utilized for the extraction of Zn, P, Cd, Pb, Fe, Mn, Mg, Cu, Ca, Al, Na and K from wide range of food materials (wheat flour, brown bread, total diet and skimmed milk powder). Critical parameters affecting MAE process such as extractant concentration (HClO4 and H2O2), extraction time and temperature were optimized to get quantitative recovery of elements. The methodology was optimized by using two representative food based reference materials; wheat flour NIST-1567a and non-fat milk powder NIST-1549. The solid residues remained after MAE extraction was filtered and the supernatant was diluted 3–10 times with high purity water before analysis by ICP-OES. These studies indicate that the method is a rapid (within 15 min) and quantitative recoveries (>95%) for all the selected elements, were obtained using a 2% (v/v) HClO4 and 4% (v/v) H2O2 mixture as extractant. The optimum microwave extraction parameters obtained were: temperature - 140 °C, pressure - 6 bar and time - 10 min. The accuracy of the proposed MAE method was further evaluated analyzing two more certified reference materials, brown bread BCR-191 and total diet NIST-1548. It was possible to perform the extraction of up to 0.5 g of food materials using an optimized extractant mixture of 2% (v/v) HClO4 and 4% (v/v) H2O2 with resultant carbon content lower than 3470 mg L−1. The results showed no significant statistical difference (Student's t-test, 95% confidence level) between found values and certified values. The recoveries ranging from 97 to 104% were obtained with RSD values <8%. Under optimal conditions, the limits of detection (LOD) of selected elements ranged from 0.01 mg kg−1 to 7.8 mg kg−1 were obtained for ICP-OES in conjunction with present MAE method. The optimized MAE approach was subsequently applied to wheat flour samples of a few leading brands purchased from local super market. These investigations reveal that the proposed MAE method in conjunction with ICP-OES can be utilized for the quantitative determination of various elements in wide range of food materials on regular basis.

A greener microwave-assisted extraction method for rapid spectroscopic determination of selected metals in river and freshwater sediment certified reference materials

ABSTRACTThe current study describes development of novel, cost-effective, rapid and greener microwave-assisted extraction (MW-AE) method using diluted hydrogen peroxide (H2O2) and 400 µL of concentrated aqua-regia for the extraction of 10 selected metals (Ba, Cr, Cu, Co Fe, Mn, Ni, Pb, V and Zn) in sediment certified reference materials (CRMs), prior to inductively coupled plasma-optical emission spectroscopic analysis. The optimum extraction conditions were achieved when 0.2 g of sediment was extracted with 1 mol L−1 of H2O2 (12.00 mL) and 400 µL of concentrated aqua-regia, at 180°C microwave extraction temperature for 30 min. Accuracy of the proposed MW-AE method was evaluated by using river (LGC6187) and freshwater (CRM015-050) sediment CRMs. Quantitative extraction recoveries of 80–120% in LGC6187 and 74–124% in CRM0150-050 were obtained with acceptable precision (0.4–1.0%). The proposed extraction method has a clear advantage over classical approaches as 1 mol L−1 H2O2 was used instead of notorious acidic mixture (Hydrochloric acid/ nitric acid/ hydrofluoric). The method detection limits (MDLs) of 0.03–0.9 μg g−1 were obtained for all the investigated metals and were fairly comparable with the MDLs of the published literature reports. Therefore, the proposed MW-AE method can be routinely used for monitoring of metal ions in various river and fresh water sediments.

Validation of a Rapid Microwave-Assisted Extraction Method and GC-FID Quantification of Total Branched Chain Fatty Acids in Lamb Subcutaneous Adipose Tissue.

A rapid microwave-assisted extraction and derivatization of three branched chain fatty acids (BCFA): 4-methyloctanoic acid (MOA), 4-ethyloctanoic acid (EOA) and 4-methylnonanoic acid (MNA) from subcutaneous adipose tissue (SAT) of lamb was developed and validated. Linearity was excellent (R2 > 0.99), and the limits of detection and quantification (μg/mL) were between 0.03 to 0.05 and 0.04 to 0.06, respectively. The relative response factors were 0.9416, 1.2840, and 1.0370 determined with high precision (RSD: 5.8%, 6.7%, and 5.9%) for MOA, EOA, and MNA, respectively. The accuracy, recoveries and matrix effect were 92.5% to 108.3%, 103.1% to 103.8%, and 89.3% to 101.9%, respectively. Analysis of 24 SAT samples can be done in under 4 hr. The levels of total BCFA in SAT of lambs were in good agreement with levels found in literature using more time-consuming method. PRACTICAL APPLICATION: Microwave-assisted preparation and quantification of branched chain fatty acids (BCFA) in lamb subcutaneous adipose tissue (SAT) was developed and validated. This method requires the use of less toxic chemicals and a relatively higher number of samples can be analyzed in a short period of time in comparison to established methods of fatty acid analysis. The validated method met the internationally accepted standards, and the BCFA levels in lamb SAT were consistent with published values; consequently, the method can be used for future analyses.

Simultaneous determination of seven bioactive components in Guizhi Fuling capsule by microwave-assisted extraction combined with ultra performance liquid chromatography tandem mass spectrometry

A simple, rapid and reliable microwave-assisted extraction (MAE) combined with ultra performance liquid chromatography tandem mass spectrometry method was developed for simultaneous determination of the seven bioactive constituents in Guizhi Fuling capsule (GFC), namely gallic acid, amygdalin, albiflorin, paeoniflorin, paeonol, cinnamic acid and pachymic acid, respectively. The operation of MAE optimised through orthogonal array design experiment was performed at 80°C for 10 min with methanol–water (70:30, v/v) as the extracting solvent. The method was validated including intra- and inter-day precision, repeatability and stability, with relative standard deviation less than 3.9%, 3.3%, 4.4% and 3.1%, respectively. All analytes showed the good linearity (r >0.999), and their average recoveries varied between 98.2% and 101.2%. The results indicated that this method was simple, effective and suitable for the quality control of GFC.

A rapid microwave-assisted acid extraction method based on the use of diluted HNO3-H2O2 followed by ICP-MS analysis for simultaneous determination of trace elements in coal samples

Before coal processing such as pyrolysis, liquefaction, gasification and combustion, it is very crucial to monitor the trace element concentration levels as that determines the coal quality. Therefore, the current study describes the development of microwave-assisted acid extraction (MW-AAE) method for extraction of 15 trace elements in coal samples prior to their determination using inductively coupled plasma-mass spectrometry. Diluted HNO3-H2O2 was used in order to reduce reagents amount used, eliminate matrix interferences caused by concentrated acids and to decrease waste produced in analytical laboratories. The optimisation of the proposed extraction method was carried out by using a full factorial design (24) involving four factors; that is, temperature, extraction time, HNO3 and H2O2 concentrations. The optimum conditions for the MW-AAE procedure were found to be 200°C, 5 min, 5 mol L−1 and 2 mol L−1 for temperature, extraction time, HNO3 and H2O2 concentrations, respectively. Under optimum conditions, the accuracy of the MW-AAE method was examined by analysing three coal certified reference materials (SARM 18, 19 and 20) and recoveries of 80–115% were achieved for V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Sr, Zr, Cs, Ba, Pb and U, except for Ti (10–25%) and Hf (27–70%). In addition, the precision of the proposed method, expressed in terms of relative standard deviation (SD) (n = 15), was within the accepted range (≤3.5%). The method detection limits of 0.001–0.57 µg g−1 for all trace elements under the investigation were similar to the literature reported work, except for Ti (4.00 µg g−1).

A hierarchical cluster analysis of ten index constituents based on microwave-assisted extraction by UHPLC-MS/MS for the evaluation and quality control of Cortex Juglandis Mandshuricae

A novel and rapid microwave-assisted extraction combined with UHPLC-MS/MS method was developed for the quality control of ten index constituents in Cortex Juglandis Mandshuricae.

A single-step microwave-assisted acid extraction of total sulphur in coal samples followed by ICP-OES determination

A rapid microwave-assisted acid extraction (MW-AAE) procedure using a dilute [HNO3–H2O2] mixture followed by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis has been developed for the determination of total sulphur in coal samples. Parameters affecting the MW-AAE such as extractant concentration, microwave temperature, extraction time, coal amount and HNO3 : H2O2 volume ratio were optimized by using a certified reference material (SARM 20) in order to attain total sulphur quantitative recoveries. The optimum conditions for the extraction procedure were found to be 180 °C, 5 min, 3 mol L−1, 3 mol L−1, 0.05 g and 2 : 1 for microwave temperature, extraction time, [HNO3], [H2O2], coal amount and HNO3 : H2O2 volume ratio, respectively. Under optimum conditions, the accuracy of the MW-AAE method was examined by analyzing three coal certified reference materials (SARM 18, 19 and 20) and quantitative recoveries (83–102%) were achieved. Additionally, the precision of the proposed method, expressed in terms of relative standard deviation (n = 15), was satisfactory (≤3%). The method limit of detection (0.026 μg g−1) and method limit of quantification (0.087 μg g−1) for sulphur analysis were relatively good as compared to work reported in the literature.

Rapid microwave-assisted acid extraction of southern pine waste wood to remove metals from chromated copper arsenate (CCA) treatment

Abstract Recovery of metals from chromated copper arsenate (CCA)-treated southern pine wood particles was investigated by extraction in a microwave reactor with binary combinations of acetic acid (AA), oxalic acid (OxA), and phosphoric acid (PhA). Use of OxA was not successful, as insoluble copper oxalate complexes impeded copper removal. The combination of OxA and AA also had adverse effects on copper extraction. In contrast, the combination of AA and PhA enhanced the chromium recovery rate. The highest recovery rate of metals could be achieved with a mixture of 2.75% PhA and 0.5% AA at 130°C for 10 min in the microwave oven. The total recovery rate approached 100% for arsenic, 96.7% for chromium, and 98.6% for copper in a one-step process.

A simple and rapid microwave-assisted extraction method using polypropylene tubes for the determination of total mercury in environmental samples by flow injection chemical vapour generation inductively coupled plasma mass spectrometry (FI-CVG-ICP-MS)

Presented here is the development of a simple, rapid and cost-effective microwave-assisted extraction (MAE) method using closed polypropylene tubes (PP) and a domestic microwave oven for the determination of total mercury in a wide variety of environmental samples (coal, coal-fly ash, sediments and sludges). Extraction of mercury was achieved using microwave energy with a mixture of HNO3–thiourea as extractant for subsequent determination by flow injection chemical vapour generation inductively coupled plasma mass spectrometry (FI-CVG-ICP-MS). Two types of reference materials certified for mercury; Coal fly ash NIST-1633b and estuarine sediment ERM-CC-580 were taken to optimize extraction parameters such as microwave power, extraction time and sample amount for the quantitative recovery of mercury. The supernatant obtained upon centrifugation was used for analysis. Quantitative recoveries of mercury were obtained using 30% HNO3–0.02% thio-urea mixture with 30 s irradiation time at a microwave power of >640 W for 500 mg sample weight. The results obtained here were in good agreement with the certified values with an overall precision of better than 5% in all the cases. The limit of detection of the proposed method in conjunction with FI-CVG-ICP-MS was obtained to be 0.9 ng g−1. A closed-microwave extraction procedure based on US EPA method (3051A) was used for the determination of mercury for comparison purposes. The optimized MAE procedure was successfully applied to real samples.

A cost-effective and rapid microwave-assisted acid extraction method for the multi-elemental analysis of sediments by ICP-AES and ICP-MS

A very simple, cost-effective and rapid single-step microwave-assisted leaching procedure using screw-capped polypropylene (PP) tubes and a domestic microwave oven has been developed for the extraction of elements from sediments followed by their analysis using inductively coupled plasma spectrometric techniques (ICP-AES/ICP-MS). Parameters affecting the microwave-assisted extraction such as extractant concentration, microwave irradiation time, microwave power and sample amount were optimized to get quantitative recovery of elements by taking two certified reference materials: stream sediment GBW-7312 and marine sediment IAEA-433. The supernatant obtained upon centrifugation was used for analysis of various elements: Na, K, Ca, Mg, Fe, Al, Li, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Tl, Pb and Bi. Quantitative recoveries of elements of interest were obtained using a mixture of 30% HNO3 + 5% HF with 30 s irradiation time at a microwave power of 640 W for <500 mg sample weight. The results obtained here were in good agreement with the certified values with an overall precision of better than 10%. The obtained results showed that the present method of microwave assisted leaching (employing 30% HNO3 + 5% HF) of sediment reference materials without resorting to total digestion produced an efficient attack of the most important metal bearing mineral phases and the quantitative recoveries obtained here showed complete leaching of the elements of interest. The procedure is especially attractive as it requires a microwave irradiation time of less than a minute and is thus extremely rapid.

Examination of the effect of dose-death interval on detection of meperidine exposure in decomposed skeletal tissues using microwave-assisted extraction

The effect of dose-death interval and tissue distribution on the detection of meperidine in selected skeletal tissues was examined using a rapid microwave-assisted extraction (MAE) methodology. Rats ( n = 14) were dosed with 0 ( n = 2) or 30 mg/kg ( n = 12) meperidine (i.p.). Drug-positive rats were sacrificed with CO 2 after 20, 30, 90 and 150 min ( n = 3 per group). Heart blood was collected immediately after death. Tibiae were excised and frozen for further analysis. The remaining carcasses were allowed to decompose outside in secured cages to the point of complete skeletonization in a rural Northern Ontario location during the late summer months. Vertebrae and pelvi were collected for each animal. Tibial marrow was homogenized in 3 mL PB6 (phosphate buffer, 0.1 M, pH 6). Fresh tibiae, and decomposed vertebrae and pelvi were cleaned in PB8.5 (phosphate buffer, 0.1 M, pH 8.5) and sonicated to remove remaining soft tissue. Samples of dried, ground bone (0.5–1 g) suspended in 2 mL PB6 were then irradiated in a domestic microwave oven (1100 W) at atmospheric pressure for 15 min. Samples of vertebral bone (1 g) were also extracted by passive incubation in methanol (3 mL, 50 °C, 72 h). All supernatants then underwent solid-phase extraction and analysis by GC/MS, using electron impact ionization in the Selected Ion Monitoring (SIM) mode. Mean GC/MS responses for each tissue type were negatively correlated with dose-death interval, with correlation coefficients ranging from −0.32 to −0.87. Analysis of variance showed dose-death interval to be a main effect ( p < 0.05) with respect to GC/MS response for blood, marrow, tibial epiphyses prepared by MAE, and vertebral bone prepared by passive extraction, but not for tibial diaphyses, pelvi or vertebrae prepared by MAE. Overall, MAE is advantageous as a rapid extraction tool for screening purposes in skeletal tissues, but assignment of significance to quantitative expressions of skeletal drug concentrations is complex and should be approached with caution.

Microwave-Assisted Acid Extraction of Selenium from Medicinal Plants Followed by Electrothermal Atomic Absorption Spectrometric Determination

A simple and rapid microwave-assisted extraction (MAE) of selenium (Se) from medicinal plants was investigated using different concentrations of nitric acid and hydrochloric acid, sample mass, heating time, microwave energy, and plant particle size. The optimization strategy was carried out using multivariate methodologies. Electrothermal atomic absorption spectrometry was used to determine Se. The accuracy of the optimized procedure was evaluated by using certified reference materials with certified values for Se and a microwave-assisted acid digestion (MD) method for comparative purpose. No significant difference was observed (P > 0.05) when comparing the values obtained by the proposed MAE and MD methods (paired t-test). Under the optimum operating conditions, the LOD obtained from the standard calibration curve was 0.012 microg/L for Se. The average RSD of the MAE method varied between 4.05 and 7.53% (n = 6). The proposed method was successfully applied for the determination of Se in medicinal plants used as remedies for cancerous and infection diseases.

Optimization of a microwave-assisted extraction of secondary metabolites from crustose lichens with quantitative spectrophotodensitometry analysis

A focused and rapid microwave-assisted extraction (MAE) process was carried out and optimized for secondary metabolites from crustose lichens using Taguchi experimental design and quantitative analysis on TLC by a Camag ® spectrophotodensitometer. The procedure was improved by quantitative determination of norstictic acid (NA), a common depsidone isolated from Pertusaria pseudocorallina (Sw.) Arn. Various experimental parameters that can potentially affect the NA extraction yields including extraction time, irradiation power, volume and the percentage of tetrahydrofuran (THF) were optimized. Results suggest that THF percentage and solvent volume were statistically the most significant factors. The optimal conditions were determined as follows: THF level of 100%, solvent volume of 15 mL, microwave power of 100 W and extraction time of 7 min. Compared to the reflux method, MAE showed a drastic reduction of extraction time (7 min vs. 3 h) and solvent consumption (15 mL vs. 30 mL). The NA in total yield was 90% using the two methods. The optimal conditions were applied to other crustose lichens, Aspicilia radiosa, Diploicia canescens and Ochrolechia parella for the extraction of NA, diploicine (DP) and variolaric acid (VA), with 83%, 90% and 95% of recovery, respectively.

Optimization of a rapid microwave-assisted extraction method for the simultaneous determination of opiates, cocaine and their metabolites in human hair

A rapid and cleanup-free microwave-assisted extraction (MAE) method is proposed for the simultaneous extraction of six illegal drugs of abuse – cocaine, benzoylecgonine (BZE), cocaethylene (CCE), morphine, 6-monoacethylmorphine (6AM) and codeine – from human hair samples. The analytes were determined using high performance liquid chromatography (HPLC) with photodiode array UV detection. The influence of several variables on the efficiency of the MAE procedure was investigated in detail by a multi-objective optimization approach based on a hybrid experimental design (17 experiments) and desirability functions. Six drugs were successfully extracted from human hair with recoveries close to 100% and good reproducibility (<3.6% RSD) under the optimal MAE conditions: 11 mL dichloromethane (DCM) extraction solvent, 60 °C extraction temperature, 9 min extraction time and 0.5 mL of methanol (MeOH) added to 50 mg of the hair sample in the extraction vessels. Limits of quantification of 0.2 ng mg −1 were found for the studied compounds. A comparison of sample preparation procedures, including MAE, enzymatic digestion and digestion by aqueous acids, was also conducted. The results indicated that the global behaviour of sample procedures provided similar satisfactory recoveries ranging from 86 to 100%. Indeed, the MAE procedure resulted in a reduction of extraction time by 100-fold and the elimination of cleanup steps. Slightly higher recoveries of morphine, 6AM, BZE and CCE, at 1 ng mg −1 concentration level and cocaine at 40 ng mg −1 concentration level, were achieved using MAE. Lastly, the proposed MAE method was applied to several human hair samples from multidrug abusers.

Multivariate optimisation of microwave‐assisted extraction of capsaicin from Capsicum frutescens L. and quantitative analysis by 1H‐NMR

A simple and rapid microwave-assisted extraction (MAE) procedure combined with 1H-NMR spectrometry was developed and optimised for the extraction and quantitative determination of capsaicin in Capsicum frutescens. The influence of experimental variables, including irradiation power, extraction temperature and dynamic extraction time before reaching the selected extraction temperature, on the performance of the extraction procedure was systematically studied using a Box-Behnken experimental design followed by a conventional central composite design approach. Statistical treatment of the results together with results from some additional experiments suggested optimum extraction conditions as 120 degrees C and 150 W, for 15 min with acetone as extractant. The optimised MAE method provides extracts that can be analysed quantitatively using 1H-NMR without any preliminary clean-up or derivatisation steps. In the 1H-NMR spectrum of the crude extracts the doublet signal in the delta range 4.349-4.360 ppm was well separated from other resonances in deuterated chloroform. The quantity of the compound was calculated from the relative ratio of the integral value of the target peak to that of a known amount of dimethylformamide as internal standard. In comparison with traditional Soxhlet extraction, the proposed method is less labour-intensive and provides a drastic reduction of extraction time and solvent consumption. In addition, MAE showed higher extraction yield and selectivity, with comparable reproducibility and recovery, relative to both conventional Soxhlet and sonication methods.

Speciation analysis of arsenic and selenium compounds in environmental and biological samples by ion chromatography–inductively coupled plasma dynamic reaction cell mass spectrometer

An inductively coupled plasma mass spectrometer (ICP-MS) was used as an ion chromatographic (IC) detector for the speciation analysis of arsenic and selenium. The arsenic and selenium species studied included arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB), selenite [Se(IV)] and selenate [Se(VI)]. Gradient elution using (NH 4) 2CO 3 and methanol at pH 9 allowed the chromatographic separation of all species in less than 12 min. Effluents from the IC column were delivered to the nebulization system of ICP-DRC-MS for the determination of arsenic and selenium. The potentially interfering 38Ar 40Ar + and 40Ar 40Ar + at the selenium masses m/ z 78 and 80 were reduced in intensity by approximately 3 orders of magnitude by using 0.6 mL min −1 CH 4 as reactive cell gas in the DRC while an Rpq value of 0.3 was used. Meanwhile, arsenic was determined as the adduct ion 75As 12CHH + at m/ z 89, which is more sensitive than 75As. The limits of detection for arsenic and selenium were in the range of 0.002–0.01 ng mL −1 and 0.01–0.02 ng mL −1, respectively, based on peak height. The relative standard deviation of the peak areas for five injections of 5 ng mL −1 As and Se mixture was in the range of 2–4%. The concentrations of arsenic and selenium species have been determined in urine samples collected locally. The major As and Se species in urines were AsB, DMA and probably selenosugar at concentration of 20–40, 15–19 and 17–31 ng mL −1, respectively. The recoveries were in the range of 94–105% for all the determinations. This method has also been applied to determine various arsenic compounds in two fish samples. In this study, a simple and rapid microwave-assisted extraction method was used for the extraction of arsenic compounds from fish. The arsenic species were quantitatively leached with an 80% v/v methanol solution in a focused microwave field during a period of 5 min.

Evaluation of a microwave-assisted extraction technique for determination of water-soluble inorganic species in urban airborne particulate matter

A simple and rapid microwave-assisted extraction (MAE) technique has been developed for the determination of water-soluble inorganic species (cations: Na+, NH4+, K+, Ca2+ and Mg2+ and anions: F-, Cl-, NO3-, PO4(3-) and SO4(2-)) in airborne particulate matter. The analytes were extracted under different treatment conditions such as microwave power and extraction time. They were quantified using ion chromatography. The observed concentrations and recovery yields obtained under different conditions were compared. The results of a comparison between this MAE and sonication using NIST SRM 1648 are also given in this paper. The optimized MAE technique gave results in good agreement with the values obtained by the sonication. For some ions, for example Mg2+ and K+, recovery was low with both techniques. The results demonstrated that the optimized MAE is fast and efficient compared with conventional ultrasonic extraction. Urban airborne particles were collected and subjected to the MAE followed by the IC analysis to determine the relative proportions of different water-soluble inorganic species. These results are briefly discussed.