scholarly journals Trace Arsenic Determination in a TiO2 Pigment Matrix Using Electrothermal Atomic Absorption Spectrometry

2019 ◽  
Vol 25 (2) ◽  
pp. 123-131
Author(s):  
Matjaž Finšgar ◽  
Tamara Govejšek ◽  
Ksenija Gradišek
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Microwave Digestion ◽  
Pyrolytic Graphite ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Absorption Spectrometry ◽  
Calibration Procedure ◽  
Chemical Modifier ◽  
Relative Standard ◽  
Arsenic Determination

This work describes the use of electrothermal atomic absorption spectrometry in combination with a pyrolytic graphite-coated tube with a platform for trace arsenic (As) determination in titanium dioxide (TiO2) pigment. This type of matrix is challenging, as complete digestion in hydrofluoric acid-containing solution is needed. First, closed-vessel microwave digestion was performed for the full-sample decomposition. Next, a temperature program was optimized for drying, pyrolysis, and atomization temperatures. Furthermore, the use of a chemical modifier mixture was proposed that reduced the background contribution and prevented significant analyte loss and therefore improved the analytical procedure. The optimized method was validated for the detection (LOD) and quantification (LOQ) limits, the linear concentration range, accuracy, and precision. Special attention was devoted to the matrix-matching solutions in the calibration procedure. Linearity was confirmed in the 5.0 to 100.0 µg/L concentration range ( R2 = 0.999). The average recovery for 16 different real TiO2 pigment samples was 92.0%, and the relative standard deviation value for six replicate measurements was ≤10.4%. Moreover, the LOD and LOQ in terms of the TiO2 pigment mass was determined to be 0.2 µg/(g TiO2) and 0.7 µg/(g TiO2), respectively. The latter complies with Commission Directive 2008/128/EC, which does not allow more than 3 µg As/(g product) as the specific criteria of purity. Finally, based on scanning electron microscopy analysis of unused and several times used pyrolytic graphite-coated tubes, usage of the tube 250 times before replacement is recommended.

scholarly journals Determination of Thallium in Potassium Chloride and Electrolyte Replenishers by Electrothermal Atomic Absorption Spectrometry

2004 ◽  
Vol 87 (4) ◽  
pp. 986-990 ◽  
Author(s):  
Isoshi Nukatsuka ◽  
Ryo Horiguchi ◽  
Hiroyuki Seitoh ◽  
Kunio Ohzeki ◽  
Fumihide Miyashita
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Potassium Chloride ◽  
Atomic Absorption ◽  
Fine Particles ◽  
Membrane Filter ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Absorption Spectrometry ◽  
Chloride Ions ◽  
Chemical Modifier ◽  
Relative Standard

Abstract Thallium in potassium chloride and electrolyte replenishers was determined by electrothermal atomic absorption spectrometry (ETAAS) with direct injection of a resin suspension. Thallium(III) was extracted on fine particles of a cellulose nitrate resin (CNR) from dilute HCl (pH 1.6) in the presence of ammonium pyrrolidine-1- carbodithioate. The CNR particles were collected on a membrane filter by filtration under suction, suspended in 1.0 mL 10mM HNO3, and then delivered directly to ETAAS as the suspension. The effects of chloride ions were thoroughly investigated. The results showed that the addition of 0.5mM NaCl to the suspension (10mM HNO3) was recommended, after CNR and a membrane filter holding the CNR were washed thoroughly with 0.025M HCl, to eliminate interference from chloride ions. No chemical modifier was required. Extraction from the solution containing up to 2M chloride ion was allowable. The proposed method gave a concentration factor of 50 for a 50 mL sample volume. The detection limit (3σ, n = 5) was 1 ng (20 pg/mL). The relative standard deviation was 4.9% (n = 5) at 30 ng level of thallium. The content of thallium in potassium chloride was 15.7–32.8 ng/g, and in electrolyte replenishers was 0.18–4.16 ng/mL.

scholarly journals Determination of Lead, Cadmium, Zinc, Copper, and Iron in Foods by Atomic Absorption Spectrometry after Microwave Digestion: NMKL1 Collaborative Study

2000 ◽  
Vol 83 (5) ◽  
pp. 1189-1203 ◽  
Author(s):  
Lars Jorhem ◽  
Joakim Engman ◽  
B-M Arvidsson ◽  
B Åsman ◽  
C Åstrand ◽  
...  
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Tissue Sample ◽  
Certified Reference Materials ◽  
Microwave Digestion ◽  
Collaborative Study ◽  
Absorption Spectrometry ◽  
Relative Standard ◽  
Cadmium Zinc

Abstract A method for determination of lead, cadmium, zinc, copper, and iron by atomic absorption spectrometry (AAS) after microwave digestion was subjected to a collaborative study in which 16 laboratories participated [including users of inductively coupled plasma (ICP) and ICP–mass spectrometry (MS)]. The types of samples included in the study were minced fish, wheat bran, milk powder, bovine and pig liver, mushroom, 2 simulated diets, and bovine muscle; the last 4 were certified reference materials. These were analyzed as single (4 samples), double blind (1 sample), or split level (2 samples) samples. Before the collaborative study, a pretrial was conducted in which 4 ready-made solutions and one fish tissue sample were analyzed for Pb and Cu. The reproducibility relative standard deviation (RSDR) values, for results above the detection limit, ranged from 59% at 0.155 mg/kg to 16% at 1.62 mg/kg for Pb, from 28% at 0.0124 mg/kg to 11% at 0.482 mg/kg for Cd, from 9.3% at 35.3 mg/kg to 1.7% at 147 mg/kg for Zn, from 39% at 0.241 mg/kg to 3.0% at 63.4 mg/kg for Cu, and from 17% at 7.4 mg/kg to 5.9% at 303 mg/kg for Fe. The RSDR values agreed well with the norms described by the International Union of Pure and Applied Chemistry. As a complement to the AAS determinations, a number of laboratories analyzed the samples either by ICP or by ICP–MS. The results of these analyses agreed well with the AAS results. On the basis of the results of the collaborative study, the method was adopted Official First Action by AOAC INTERNATIONAL.

scholarly journals Determination of Arsenic in Seafood by Electrothermal Atomic Absorption Spectrometry after Microwave Digestion: NMKL Collaborative Study

2000 ◽  
Vol 83 (6) ◽  
pp. 1423-1428 ◽  
Author(s):  
Kaare Julshamn ◽  
Arngriimur Thorlacius ◽  
Per Lea ◽  
Kjetil Barland ◽  
Kari Eidem ◽  
...  
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Blue Mussel ◽  
Collaborative Study ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Absorption Spectrometry ◽  
Method Performance ◽  
Relative Standard ◽  
Standard Deviations

Abstract Eight laboratories participated in an interlaboratory method performance (collaborative) study of a method for the determination of arsenic in foodstuffs of marine origin by electrothermal atomic absorption spectrometry after wet digestion using a microwave oven technique. The study was preceded by a practice round of familiarization samples. The method was tested on 8 materials (cod roe, krill, blue mussel, saithe, scampi, cod fillet, shrimp, and cod extract) ranging in As content from 2 to 75 mg/kg. The materials were sent to participants in the study as blind duplicates, and the participants were asked to perform single determinations on each sample. Repeatability relative standard deviations (RSDr) for As ranged from 6.8 to 17.4%. Reproducibility relative standard deviations (RSDR) ranged from 7.6 to 24%. The highest RSDR value was found for the sample with the highest concentration of As.

scholarly journals Validation of a Digestion System Using a Digester Block/Cold Finger System for the Determination of Lead in Vegetable Foods by Electrothermal Atomic Absorption Spectrometry

2011 ◽  
Vol 94 (3) ◽  
pp. 942-946 ◽  
Author(s):  
Robson M De Jesus ◽  
Mario M S Junior ◽  
Geraldo D Matos ◽  
Ana Dos M P Santos ◽  
Sérgio L C Ferreira
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Ammonium Phosphate ◽  
Absorption Spectrometry ◽  
Chemical Modifier ◽  
Cold Finger ◽  
Average Value ◽  
Spinach Leaves

Abstract This paper presents the validation of a system for sample digestion using a digester block/ cold finger to determine the lead content in vegetables by electrothermal atomic absorption spectrometry (ETAAS). After mineralization, lead contents were determined by ETAAS using a calibration curve based on aqueous standards prepared in 2.60 M nitric acid solutions containing 5 μg ammonium phosphate as chemical modifier. A pyrolysis temperature of 900°C and atomization temperature of 2000°C were used. This method allowed the determination of lead with a characteristic mass of 35 pg; LOD and LOQ of 0.6 and 2 ng/g, respectively, were found. The precision was investigated in terms of reproducibility and repeatability. Reproducibility was estimated by analysis of nine different portions of a certified reference material (CRM) of spinach leaves, and the repeatability was determined through the analysis of nine aliquots of the same solution. The reproducibility and repeatability were found to be 4.27 and 2.94% RSD, respectively. The accuracy was confirmed by analysis of whole meal flour, spinach leaves, and orchard leaves CRMs, all furnished by the National Institute of Standards and Technology. Lead contents were measured using the newly developed technique in 11 different potato samples. The lead contents ranged from 12.80 to 69.27 ng/g, with an average value of 28.59 ng/g. These values were in agreement with data reported in the literature.

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