Electrothermal Atomic Absorption Spectrophotometry Research Articles

A comparison of Inductively Coupled Plasma Mass Spectrometry with Electrothermal Atomic Absorption Spectrophotometry for the Determination of Trace Elements in Blood and Urine from non Occupationally Exposed Populations

Quadrupole Inductively coupled plasma mass spectrometric (QICP-MS) and electrothermal atomic absorption spectrophotometric (ETAAS) methods for the determination of Pb and Cd in whole blood and Al, Cd, Co and Ni in urine were compared. Simple sample pretreatments were used for both instrumental techniques. Urine samples were diluted with either Millipore water or dilute HNO3, while blood samples were diluted with a solution containing either 0.14M NH3 or 0.03 M NH3, 0.05% EDTA and 0.05% Triton X-100 in Millipore water. Scandium, yttrium and indium were used as internal standards for ICP-MS measurements and (NH4)2HPO4 as a chemical modifier for the determination of Pb and Cd by ETAAS. For ICP-MS analysis, pneumatic nebulization was used for introduction of urine samples and flow injection for introduction of blood samples. Matrix matched standards were used for all calibrations and methods were validated by analyzing reference materials and samples from external quality assurance programmes. Concentrations of the listed metals were determined in blood and urine samples obtained from a healthy non occupationally exposed population and reference samples, using both instrumental techniques. The study group (n = 90) was randomly selected from a study population (n = 220) recruited from three regions considered representative of the environment encountered by the majority of the United Kingdom population. Males and females were equally represented and ranged in age from 17-65 yrs. The correlation between results obtained by the two techniques was good for all elements measured, ranging from r = 0.88 for Co in urine to r = 0.99 for both Pb and Cd in blood.

Atomization of Al in a tungsten coil electrothermal atomic absorption spectrophotometer

Electrothermal atomic absorption spectrophotometry of Al in a tungsten coil atomizer was evaluated and applied for its determination in hemodialysis fluid. The system was mounted on a Varian Spectra AA-40 spectrophotometer with continuum background correction and all measurements, in peak height absorbance, were done at 309.3 nm. The purge gas was a mixture of 90% Ar plus 10% H2. Observation height, gas flow, drying, pyrolysis and atomization steps were optimized. The heating program was carried out by employing a heating cycle in four steps: dry, pyrolysis, atomization and clean. The determination of Al in hemodialysis solutions was performed by using a matrix-matching procedure. Al in hemodialysis solutions was determined by TCA and by electrothermal atomization with a graphite tube atomizer. There is no differences between results obtained by both methods at a confidence level of 95%. The characteristic mass of Al by using the TCA was 39 pg and the detection limit was 2.0 μg l−1.

Determination of Cobalt in Animal Feces by Tungsten Coil Atomic Absorption Spectrophotometry

An alternative analytical procedure for cobalt determination by tungsten coil electrothermal atomic absorption spectrophotometry (TCAAS) was developed to determine the liquid ruminal passage rate (turnover) of Co-EDTA in sheep feces. A matrix-matching procedure and a selective extraction of Co in 1.0 mol l-1 HCl were evaluated in order to correct and minimize the interference effects caused by sample matrices. As application, six sheep received at the same time one dose of the marker (Co-EDTA); thier fecal samples were collected in intervals of 6 h during 90 h. The Co amounts determined in the dry sheep feces by TCAAS were compared with those obtained by a flow injection catalytic spectrophotometric method. The characteristic mass and the detection limit, both based on peak height absorbance, were 23.1 and 19.1 pg, respectively, for 10 ml of sample volume in the samples of sheep feces. The rsd was 0.5% for 10 consecutive injections of 20.0 mg Co l-1. The accuracy was assessed by employing the paired t-test at 95% confidence level; there was no significant difference for Co content determined by TCAAS and by flow injection spectrophotometry.

The aluminum content in some patch test allergens.

The Al content of 18 patch test allergens were measured by electrothermal atomic absorption spectrophotometry. It was found that these preparations contained Al in various amounts. We conclude that the presence of Al in patch test allergens may interfere with the diagnosis and evaluations of patients to whom the test is applied.

Trace element reference values in tissues from inhabitants of the European Union. X. A study of 13 elements in blood and urine of a United Kingdom population

Electrothermal atomic absorption spectrophotometry (ETAAS), inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA) were used for the quantitative determination of 13 trace elements in urine and seven trace elements in whole blood of healthy unexposed British subjects living in three regions of the United Kingdom. Careful control of pre-analytical and analytical factors have enabled the results obtained from more than 200 individuals to be used in proposing reference intervals for the following elements; Al, As, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Se, Tl in urine, and Cd, Cr, Hg, Mn, Pb, Se and Tl in blood.

A new protocol for the measurement of picomole quantities of magnesium in rat renal tubular fluid.

The analysis of picomolar quantities of magnesium by electrothermal atomic absorption spectrophotometry (EAAS) was studied using a Perkin-Elmer-Zeeman 3030 spectrophotometer. The absorbance signal was not heavily dependent on the atomization temperature, but was greatly reduced when ashing temperatures in excess of 1200 degrees C were applied. The magnesium signal was significantly depressed in the presence of excess chloride in the sample matrix. However, use of NH4NO3 as a matrix modifier was sufficient to overcome this artefact. The analytical sensitivity was 0.15 absorbance units pmol-1 and the detection limit was 0.04 pmol. Using nanolitre constriction pipettes to dispense standards, the mean coefficient of variation was 5%. Measurement of magnesium handling in the rat proximal convoluted tubule revealed a significant correlation between the tubular fluid-to-plasma ultrafiltrate (TF/UF) concentration ratio for magnesium and the tubular fluid-to-plasma (TF/P) concentration ratio for [3H]inulin (r2 = 0.56, n = 17). This indicated that magnesium is concentrated during its passage along the proximal tubule. In contrast, this was not the case for sodium (r2 = 0.11, n = 16). Mean (TF/UF)Mg (1.16 +/- 0.07, n = 17) for random punctures was significantly greater than that for sodium ((TF/UF)Na = 1.02 +/- 0.02, n = 16). Despite concentration of magnesium in the lumen, significant net reabsorption of magnesium was observed along the length of the tubule (fractional reabsorption, FRMg = 19.4 +/- 3.0%, n = 17). In conclusion, EAAS provides a highly sensitive, reproducible and technically simple method for measuring picomolar quantities of magnesium in renal tubular fluid.

Intake of Chromium by the Adult Population of Mumbai City

Electro Thermal Atomic Absorption Spectrophotometry (ET-AAS), is used for the determination of chromium (Cr) in a variety of environmental matrices. The detection limit for the estimation of Cr is 2 pg absolute for a volume injection of 20 μl. The precision of the method is established by analysing Cr from a synthetic mixture containing various elements in different qualities (0.5–10 ppm) and is found to be within ± 8%. The reliability of estimation is further assessed through the analysis of Standard Reference Materials (SRMs) of soil, hay, milk powder and lake sediment obtained from IAEA.

Concentration of metal elements in the blood and urine in the patients with cementless total knee arthroplasty.

Titanium (Ti), cobalt (Co) and chromium (Cr) element concentrations in the whole blood and urine specimen in 40 patients with cementless total knee arthroplasty were determined by the electrothermal atomic absorption spectrophotometry. Their ages ranged from 55 to 78 years (mean, 65 years). Twenty of them had loosening of prosthesis and underwent revision surgery, including 4 subjects with Ti-6Al-4V alloy prosthesis and 16 subjects with Co-Cr-Mo alloy prosthesis. The other 20 patients had well-functioning stable prosthesis, including 5 subjects with Ti-6Al-4V alloy prosthesis and 15 subjects with Co-Cr-Mo alloy prosthesis. The mean duration of prostheses implantation in patients with loosened or well-functioning prostheses were 6.5 and 4.0 years, respectively. The control group consisted of 20 age-matched normal subjects who did not undergo any metal implant surgery. Analysis of variance showed that the metal element concentrations in the whole blood, either Co, Cr or Ti, was statistically higher in the patients with loosened prosthesis than the other two groups. However, the metal element concentrations in the urine did not show any difference. The linear regression analysis showed a moderate positive relationship between the metal element concentrations, either Co or Cr elements, in whole blood and urine only in the patients with loosened prostheses. In conclusion, elevated concentration of metal elements may indicate a loosening of prosthesis while the clinical significance of the metal element concentration in the urine needs further investigation.

Lead in primary teeth from Norway: changes in lead levels from the 1970s to the 1990s

Lead is one of the most important and widely distributed pollutants in the environment. In the human population children are particularly at risk. Local dentists in all 19 counties in Norway collected 2746 primary teeth from 1990 to 1994. Tooth substance from whole, ground teeth were analyzed for lead concentration by electrothermal atomic absorption spectrophotometry. The geometrical mean for the entire material was 1.27 μg lead/g tooth substance (S.D. 1.87). The mean lead levels in each of the counties were significantly lower than those obtained in a corresponding study in the 1970s. Two counties, Oslo and Vest-Agder, had significantly higher lead levels than the majority of the other counties. Tooth lead concentration and atmospheric deposition of lead in the same areas were significantly and positively correlated, as shown by analysis of naturally growing moss. We conclude that lead concentrations in primary teeth from children in Norway have been reduced by approx. 50% from the 1970s to the 1990s. The reduction probably reflects a decrease in the environmental lead burden in Norway.

Serum concentration and dietary intake of Zn in healthy institutionalized elderly subjects

We determined the serum concentrations and dietary intake of zinc, as indicators of Zn status, in 44 healthy institutionalized elderly subjects in Granada (Spain) (mean age 81.4 ± 7.9 years). Determination of Zn in serum was carried out by electrothermal atomic absorption spectrophotometry. Serum samples had a mean Zn concentration of 10.49 ± 3.5 μmol/l. No significant differences were found in the serum levels of Zn as regards the sex of the subjects. However, concerning Zn intake, determined by a 7-day weighed food record, a significant statistical difference ( P < 0.001) was found between men and women, with mean values of 10.01 ± 1.76 mg/day and 7.33 ± 1.33 mg/day, respectively. Application of regression analysis to the serum concentration of Zn and other nutritional parameters shows a statistically significant correlation ( P < 0.05) between serum levels of Zn and the body mass index. The lack of statistical correlation between the serum concentration of zinc and its intake indicates that this index cannot be used as an indicator of zinc status in the elderly.

Pharmacokinetic monitoring of anticancer drugs at King Faisal Specialist Hospital, Riyadh, Saudi Arabia.

Pharmacokinetic monitoring of anticancer agents has the potential to become of considerable clinical value. Recognizing this and the leading role of the King Faisal Specialist Hospital and Research Centre (KFSH & RC) in healthcare delivery in the Kingdom of Saudi Arabia, particularly in oncology, the authors have established a pharmacokinetics service and research laboratory equipped with the state-of-the-art analytical instrumentation. After the acquisition of these instruments, we initiated research work that lead to the development of improved analytical methods for methotrexate and 7-OH methotrexate (high-performance liquid chromatography [HPLC]), doxorubicin (HPLC), etoposide (HPLC), 5-fluorouracil (HPLC), mitoxantrone (HPLC), mesna and dimesna (HPLC), taxol (HPLC), aminoglutethimide (HPLC), tamoxifen (HPLC), and acrolein (HPLC), cisplatin or carboplatin (electrothermal atomic absorption spectrophotometry, ETAAS), cyclophosphamide (gas chromatography) and CCNU and BCNU (gas chromatography). Currently, most of these drugs are monitored selectively as requested by oncologists at the KFSH & RC. The authors are aware that controlled, randomized studies of the concentration-effect relationships for many of these drugs are still missing. However, the authors hope that once these studies become available, this service will be used more fully.

Detection of titanium in human tissues after craniofacial surgery.

Generally, titanium fixation plates are not removed after osteosynthesis, because they have high biocompatability and high corrosion resistance characteristics. Experiments with laboratory animals, and limited studies of analyses of human tissues, have reported evidence of titanium release into local and distant tissues. This study summarizes our results of the analysis of soft tissues for titanium in four patients with titanium microfixation plates. Energy dispersive x-ray analysis, scanning electron microscopy, and electrothermal atomic absorption spectrophotometry were used to detect trace amounts of titanium in surrounding soft tissues. A single metal inclusion was detected by scanning electron microscopy and energy dispersive x-ray analysis in one patient, whereas, electrothermal atomic absorption spectrophotometry analyses revealed titanium present in three of four specimens in levels ranging from 7.92 to 31.8 micrograms/gm of dry tissue. Results from this study revealed trace amounts of titanium in tissues surrounding craniofacial plates. At the atomic level, electrothermal atomic absorption spectrophotometry appears to be a sensitive tool to quantitatively detect ultra-trace amounts of metal in human tissue.

Systemic titanium levels in rabbits with a titanium implant in the absence of wear.

All non-noble metals and alloys will release metallic species into the body. This raises the issue of amount and fate, i.e. transport and storage, of these metal dissolution products. For titanium, the nature and extent of these systemic effects remain mostly unknown. In this study we investigated titanium levels in alleged target tissues in rabbits, both with and without a titanium implant functioning in the absence of wear, and compare these results to the limited body of literature concerning systemic levels of titanium. Titanium fibre felts were implanted into the tibia of rabbits. At various time points, lung, spleen, and muscle samples were collected from these rabbits as well as two groups of control rabbits. The samples were analysed for titanium concentration using electrothermal atomic absorption spectrophotometry. The data for the implant groups show that titanium levels in these tissues do not increase in comparison with controls up to 1 y after implantation.

Aluminum in enteral nutrition formulas and parenteral solutions.

To examine the aluminum content of several commercially available enteral nutrition formulas and parenteral solutions. Twelve enteral nutrition formulas and 10 parenteral solutions were commonly used in routine clinical care of patients and obtained from different medical companies in Turkey. The aluminum contents were determined by electrothermal atomic absorption spectrophotometry. We found that aluminum concentration in the enteral nutrition formulas and the parenteral solutions to range from 87.6 to 961.2 ng/mL and 58.4 to 1232.0 ng/mL, respectively. Careful clinical and biochemical monitoring are warranted to determine whether it will be necessary to eliminate aluminum contamination of enteral and parenteral preparations used in patients, particularly infants, with reduced kidney function who may be at risk for aluminum intoxication.

Reference Values for the Trace Elements Copper, Manganese, Selenium, and Zinc in the Serum / Plasma of Children, Adolescents, and Adults

Up to now few plasma or serum reference or serum reference values have been available for the assessment of the essential trace element supply status in different age groups covering the whole range of life range. In the present investigation, the concentrations of copper, manganese, selenium, and zinc were determined in the serum of 137 healthy children and in the plasma of 68 blood-donors. The age distribution within these groups ranged from 1 month to 18 years and from 22 to 75 years. The determinations were carried out directly by means of electrothermal atomic absorption spectrophotometry with Zeeman background compensation. The adult plasma reference values (mean +/- 2 SD) were 1.65 +/- 8.6 mumol/1 for copper, 14.3 +/- 11.4 nmol/1 for manganese, 0.80 +/- 0.36 mumol/1 for selenium, and 16.6 +/- mumol/1 for zinc. No correlation between concentration of elements and sex could be established. In the child and adolescent group, the manganese levels exhibited an age-dependent linear decrease (54% of the starting value, slope 0.92, r = 0.4, p < 0.001), the copper and the selenium concentrations, respectively, exhibited an exponential increase (107%, r = 0.59 and 174%, r = 0.61), with the highest value in the age group of 6 to 10 years. Reference ranges are established for 9 different age groups. The results reflect the known physiological data on the trace element content in the tissue of children and their diet. The present study is an important pre-requisite for diagnosis and therapy of trace element deficiencies in all age groups.

The effects of terbium on the cellular accumulation of cisplatin in MDA-MB-231 human breast tumor cells.

Cisplatin (DDP) is an effective antitumor agent limited in its efficacy by the development of tumor cell resistance. The defective accumulation of DDP has been shown to be a prominent feature in many DDP-resistant cell lines. In an effort to circumvent this problem, we examined the cellular accumulation of DDP in the presence of terbium (Tb3+). We also examined the effects of verapamil on the cellular accumulation of DDP in order to delineate the specific interaction of Tb3+ and DDP. All experiments were performed on DDP-sensitive or DDP-resistant MDA-MB-231 human breast tumor cells. The cellular accumulation of DDP and verapamil were determined by electrothermal atomic absorption spectrophotometry. Time-resolved luminescence spectroscopy was used to obtain equilibrium binding constants for the Tb3+/MDA cell complexes. We found that 100 microM Tb3+ increased DDP accumulation in the parent MDA cell line, 5.7-fold resistant MDA/A13 and 10-fold resistant MDA/CH cells by 56.2 +/- 7.4, 71.9 +/- 9.4 and 50.8 +/- 9.4%, respectively (P < 0.0001 for all MDA cell types). In contrast, 20 microM verapamil had no significant effect on DDP accumulation in the MDA cell lines. In addition, a positive correlation between the membrane binding of Tb3+ and the cellular accumulation of DDP was found to exist in the parent cell line and sublines (r = 0.9). In agreement with earlier studies, the plasma membrane of MDA cell lines contain a specific Tb(3+)-binding protein. Our findings suggest that the Tb(3+)-binding protein may be intimately associated with the accumulation of DDP in breast tumor cells.

Developmental patterns of aluminum and five essential mineral elements in the central nervous system of the fetal and infant guinea pig.

Al is found in the developing conceptus, but little information is available concerning its tissue distribution and its changes in concentration with age. Because Al has affinity for many of the same biological ligands as the essential mineral cations Ca, Mg, Zn, Fe, and Mn, we hypothesized that Al might show a pattern of developmental concentrations that was similar to one or more of these elements in the brain, a major target of Al toxicity. Concentrations of Al, Ca, Mg, Zn, Fe, and Mn were measured in spinal cord, brainstem, cerebellum, and forebrain of guinea pig fetuses on gestation day (GD) 30 and 45, at birth, and on postnatal day (PND) 3, 6, and 12. Dams were fed commercial guinea pig chow, which contained 47 micrograms Al/g. Tissue Al and Mn were measured with electrothermal atomic absorption spectrophotometry (ETAAS), and the other elements with inductively coupled axial plasma spectroscopy (ICAP-AES). Al concentrations in the brain regions were highest in spinal cord, brainstem, and cerebellum, and decreased during late gestation and lactation. Al did not show marked increases in regional brain concentrations during the final third of gestation as did Fe, Mg, and Zn. In contrast to Fe and Ca, Al did not accumulate in placenta. Al was the only element to show higher concentrations in spinal cord than in any other tissue at birth. In summary, the tissue distribution of Al did not follow that of essential cations as examined in this study.

Titanium serum and urine levels in rabbits with a titanium implant in the absence of wear

Although devices made of titanium and its alloy with 6% aluminium and 4% vanadium have been remarkably successful primarily in orthopaedic and dental applications, clinical reports have implicated the biological response to released metal from this class of metals as a cause of failure. It is our hypothesis that in the absence of wear, the amount of titanium released is small and will preferentially accumulate in local tissues. One important implication of this is that measurable quantities of titanium in serum and urine that have been observed in clinical studies result from mechanically induced or assisted release phenomena. In order to test this hypothesis, titanium levels in various tissues and fluids of animals both with and without titanium implants need to be determined. In this paper, we report the titanium concentration in serum and urine of rabbits in the absence of wear. Titanium fibre felts were implanted into the tibia of rabbits. At various time points, serum and urine samples were collected from these rabbits as well as from two groups of control rabbits. The samples were analysed for titanium concentration using electrothermal atomic absorption spectrophotometry. The data for the implant group show that titanium levels in serum and urine do not increase in comparison to controls up to one year after implantation. Some clinical studies have documented elevated titanium serum and urine levels in the presence of titanium-based prostheses. The different results from these studies can be resolved by considering titanium release mechanisms other than passive dissolution.

The determination of silver in whole blood and its application to biological monitoring of occupationally exposed groups

A sensitive and rapid technique for directly measuring silver in blood, using electrothermal atomization atomic absorption spectrophotometry (ETAAS) is described. The method can be used to analyse precisely up to 40 blood samples a day in duplicate.Well-mixed, whole blood samples, collected in EDTA, were diluted 1 + 4 with a diluent containing 40 g l.−1 ammonium dihydrogen orthophosphate and 0.5 ml l.−1 Triton X-100. Aliquots of diluted blood were then analysed by ETAAS using wall atomization with a pyrolytically coated tube.The coefficient of variation for within-run precision was 4.55% at 10 μg l.−1 and 5% at 25 μg l.−1 Between-run variation, it was 4.1% at 25 μg l.−1 The analytical recovery for the method was 98% ±3% at both 8 and 30 μg l.−1 The detection limit of the method was 0.1 μg l.−1, which was sufficiently sensitive to distinguish exposed from non-exposed individuals. Blood silver levels in unexposed subjects were found to be between <0.1 and 0.2 μg l.−1.Blood silver levels were determined in 98 occupationally exposed workers involved in bullion production, cutlery manufacture, chemical manufacture, jewellery production and silver reclamation. Blood silver levels ranged from 0.1 to 23 μg l.−1, with some of the highest levels found in silver reclaimers.

Local accumulation of titanium released from a titanium implant in the absence of wear

Titanium and its alloys, like the majority of metallic implant materials, release passive metal dissolution products. This raises the issues of amount and fate, i.e. transport, storage, and/or excretion of these metal dissolution products. In this paper we document titanium levels in tissues local to a commercially pure titanium implant in the absence of wear; compare these values to control tissues; and determine the relative contribution of the local accumulation to total release. Titanium fiber felts were implanted into the tibia of rabbits for periods up to 1 year. Bone and muscle tissue samples near the implant were collected. Using electrothermal atomic absorption spectrophotometry the samples were analyzed for titanium content. Compared to controls, titanium levels in the bone near the implant were elevated at 1-, 4-, and 12-month postoperative time points. The 12-month time point had higher periprosthetic bone titanium levels than both the 1- and the 4-month implant groups. Titanium levels in muscle tissue near the felt also indicated release was occurring. The data support the hypothesis that metal species released from titanium implants in the absence of wear have a limited solubility. As a result, they tend to remain in an area local to the implant. © 1996 John Wiley & Sons, Inc.