Elemental Analysis of Biological Matrices by Laser Ablation High Resolution Inductively Coupled Plasma Mass Spectrometry (LA-HR-ICP-MS) and High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS)

The need for elemental analysis of biological matrices such as bone, teeth, and plant matter for sourcing purposes has emerged within the forensic and geochemical laboratories. Trace elemental analyses for the comparison of aterials such as glass by inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS has been shown to offer a high degree of discrimination between different manufacturing sources. Unit resolution ICP-MS instruments may suffer from some polyatomic interferences including 40Ar16O+, 40Ar16O1H+, and 40Ca16O+ that affect iron measurement at trace levels. Iron is an important element in the analysis of glass and also of interest for the analysis of several biological matrices. A comparison of the nalytical performance of two different ICP-MS systems for iron analysis in glass for determining the method detection limits (MDLs), accuracy, and precision of the measurement is presented. Acid digestion and laser ablation methods are also compared. Iron polyatomic interferences were reduced or resolved by using dynamic reaction cell and high resolution ICP-MS. MDLs as low as 0.03 ìg g-1 and 0.14 ìg g-1 for laser ablation and solution based analyses respectively were achieved. The use of helium as a carrier gas demonstrated improvement in the detection limits of both iron isotopes (56Fe and 57Fe) in medium resolution for the HR-ICP-MS and with a dynamic reaction cell (DRC) coupled to a quadrupole ICP-MS system. The development and application of robust analytical methods for the quantification of trace elements in biological matrices has lead to a better understanding of the potential utility of these measurements in forensic chemical analyses. Standard reference materials (SRMs) were used in the development of an analytical method using HR-ICP-MS and LA-HR-ICP-MS that was subsequently applied on the analysis of real samples. Bone, teeth and ashed marijuana samples were analyzed with the developed method. Elemental analysis of bone samples from 12 different individuals provided discrimination between individuals, when femur and humerus bones were considered separately. Discrimination of 14 teeth samples based on elemental composition was achieved with the exception of one case where samples from the same individual were not associated with each other. The discrimination of 49 different ashed plant (cannabis)samples was achieved using the developed method.

Direct determination of Cu, Cd, Ni and Pb in aquatic humic substances by graphite furnace atomic absorption spectrometry

A method has been developed for the direct determination of Cu, Cd, Ni and Pb in aquatic humic substances (AHS) by graphite furnace atomic absorption spectrometry. AHS were isolated from water samples rich in organic matter, collected in the Brazilian Ecological Parks. All analytical curves presented good linear correlation coefficient. The limits of detection and quantification were in the ranges 2.5-16.7 mu g g(-1) and 8.5-50.0 mu g g(-1), respectively. The accuracy was determined using recovery tests, and for all analytes recovery percentages ranged from 93 - 98 %, with a relative standard deviation less than 4 %. The results indicated that the proposed method is a suitable alternative for the direct determination of metals in AHS.

Development of methods for the determination of cadmium and thallium in oil shale by-products with graphite furnace atomic absorption spectrometry using direct analysis.

2014

Reliability of graphite furnace atomic absorption spectrometry as alternative method for trace analysis of arsenic in natural medicinal products

Purpose: To evaluate the comparative efficiency of graphite furnace atomic absorption spectrometry (GFAAS) and hydride generation atomic absorption spectrometry (HGAAS) for trace analysis of arsenic (As) in natural herbal products (NHPs). Method: Arsenic analysis in natural herbal products and standard reference material was conducted using atomic absorption spectrometry (AAS), namely, hydride generation AAS (HGAAS) and graphite furnace (GFAAS). The samples were digested with HNO3–H2O2 in a ratio of 4:1 using microwaveassisted acid digestion. The methods were validated with the aid of the standard reference material 1515 Apple Leaves (SRM) from NIST Results: Mean recovery of three different samples of NHPs, using HGAAS and GFAAS, ranged from 89.3 - 91.4 %, and 91.7 - 93.0 %, respectively. The difference between the two methods was insignificant. A (P= 0.5), B (P=0.4) and C (P=0.88) Relative standard deviation (RSD) RSD, i.e., precision was 2.5 - 6.5 % and 2.3 - 6.7 % using HGAAS and GFAAS techniques, respectively. Recovery of arsenic in SRM was 98 and 102 % by GFAAS and HGAAS, respectively. Conclusion: GFAAS demonstrates acceptable levels of precision and accuracy. Both techniques possess comparable accuracy and repeatability. Thus, the two methods are recommended as an alternative approach for trace analysis of arsenic in natural herbal products.

Exploring potentialities of the HR-CS FAAS technique in the determination of Ni and Pb in mineral waters

National Health Surveillance Agency (ANVISA) established in the decree number 54 maximum allowed levels for Ni and Pb in mineral and natural waters at 20 µg L-1 and 10 µg L-1, respectively. For screening analysis purposes, the high-resolution continuum source flame atomic absorption spectrometry technique (HR-CS FAAS) was evaluated for the fast-sequential determination of nickel and lead in mineral waters.Two atomic lines for Ni (232.003 nm - main and 341.477 nm - secondary) and Pb (217.0005 nm - main and 283.306 nm - secondary) at different wavelength integrated absorbance (number of pixels) were evaluated. Sensitivity enhanced with the increase of the number of pixels and with the summation of the atomic lines absorbances. The main figures of merit associated to the HR-CS FAAS technique were compared with that obtained by line-source flame atomic absorption spectrometry (LS FAAS). Water samples were pre-concentrated about 5-fold by evaporation before analysis. Recoveries of Pb significantly varied with increased wavelength integrated absorbance. Better recoveries (92-93%) were observed for higher number of pixels at the main line or summating the atomic lines (90-92%). This influence was irrelevant for Ni, and recoveries in the 92-104% range were obtained in all situations.

Determination of Zinc in Lubricating Oil by Flame MS Employing Ultrasonic Extraction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Different lubricating oil treatments for the determination of Cu, Cr, Fe, Ni, Sb, Pb, and Zn by HR-CS FAAS

Microwave-assisted acid decomposition, direct dilution in kerosene, and oil-in-water emulsion were evaluated as lubricating oil pretreatment procedures for Cu, Cr, Fe, Ni, Pb, Sb, and Zn determination by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS). For wet digestion, results were compared with those obtained by Flame Atomic Absorption Spectrometry (FAAS). The ultrasound probe used in emulsions sonication contaminated samples with Cr, although better results have been observed for the other six elements in this condition. In general, recovery percentages ranging from 81-106%(Cu), 80-107%(Cr), 85-114%(Fe), 82-116%(Ni), 86-117%(Pb), 85-115%(Sb), and 81-114%(Zn) were obtained. The HR-CS FAAS showed to be faster and more sensitive than FAAS.

Exploring potentialities of the HR-CS FAAS technique in the determination of Ni and Pb in mineral waters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A simple method based on HR-CS FAAS for multi-element determination of Cu, Fe, Mn and Zn in medicinal plants

A simple method to determine Cu, Fe, Mn and Zn in single aliquots of medicinal plants by HR-CS FAAS is proposed. The main lines for Cu, Mn and Zn, and the alternate line measured at the wing of the main line for Fe at 248.327 nm allowed calibration within the 0.025 - 2.0 mg L-1 Cu, 1.0 - 20.0 mg L-1 Fe, 0.05 - 2.0 mg L-1 Mn, 0.025 - 0.75 mg L-1 Zn ranges. Nineteen medicinal plants and two certified plant reference materials were analyzed. Results were in agreement at a 95% confidence level (paired t-test) with reference values. Limits of detection were 0.12 μg L-1 Cu, 330 μg L-1 Fe, 1.42 μg L-1 Mn and 8.12 μg L-1 Zn. Relative standard deviations (n=12) were ≤ 3% for all analytes. Recoveries in the 89 - 105% (Cu), 95 - 108% (Fe), 94 - 107% (Mn), and 93 - 110% (Zn) ranges were obtained.

Synthesis, characterization and thermal behaviour of solid-state compounds of folates with some bivalent transition metals ions

Solid-state M-L compounds, where M stands for bivalent Mn, Co, Ni, Cu and Zn and L is folate (C19H17N7O6), have been synthesized. Simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray powder diffractometry, infrared spectroscopy (FTIR), TG-DSC coupled to FTIR, elemental analysis and high-resolution continuum source flame atomic absorption spectrometry technique (HR-CS FAAS) were used to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the composition, dehydration, thermal stability and thermal decomposition. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Otimização de procedimentos para a determinação de maganês em amplo intervalo de concentração por espectrometria de absorção atômica em chama

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estratégias analíticas para determinação de fósforo por espectrometria de absorção atômica com fonte contínua de alta resolução

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação de boro, enxofre e fósforo em plantas medicinais por espectrometria de absorção atômica de alta resolução com fonte contínua

Pós-graduação em Química - IQ

A espectrometria de absorção atômica com diagnóstico nutricional foliar de cana-de-açúcar e na avaliação de fertilizantes foliares

Pós-graduação em Química - IQ

Otimização de procedimento para a determinação de maganês em amplo intervalo de concentração por espectrometria de absorção atômica em chama com fonte contínua e alta resolução

This work describes instrumental strategies for the determination of Mn in a wide range concentration by high-resolution continuum source flame atomic absorption spectrometry technique (HR-CS F AAS) by means of different atomic lines (primary at 279.482 nm, secondary at 403.075 nm and alternative at 209.250 nm). These lines provided complementary concentration intervals, and large sample dilutions became unnecessary. The proposed method was applied to tap water, metal alloy certified material and foliar fertilizer. Accuracy for secondary line were evaluated by tests of significance (t Student test) with reference materials from the Institute of Technological Research of São Paulo, and the results were in agreement at the 95% confidence level. For primary and alternative lines, recovery is were in the 84-116% range and the RSD were 6.1% for all wavelengths. Analytical curves in the 0.1 - 2.0 mg L-1 (279.482 nm), 2.0 - 25 mg L-1 (403.075 nm), 25 - 500 mg L-1 (209.250 nm) intervals were obtained with linear correlation coefficient better than 0.9991. The detection limits were 3.3x10-3 mg L-1 (279.482 nm), 7.4 x 10-3 mg L-1 (403.075 nm), 3.9 mg L- 1 (209.250 nm). The found Mn concentrations were < 3.3x10-3 mg L-1 (tap water), 1.00 ± 0.04 (% m/m) (alloy IPT 25), 7235 ± 175 mg L-1 (foliar fertilizer 1), 4990 ± 132 mg L-1 (foliar fertilizer 2). A method was developed to detect interference of Fe in the Mn primary line (279.482 nm) using the ratio of absorbances of other lines of the triplet (279.827 nm and 280,108 nm).