Measurement of trace elements in murine liver tissue samples: Comparison between ICP-MS/MS and TXRF

BackgroundTrace elements exhibit essential functions in many physiological processes. Thus, for research focusing on trace element homeostasis and metabolism analytical methods allowing for multi-element analyses are fundamental. Small sample amounts may be a big challenge in trace element analyses especially if also other end points want to be addressed in the same sample. Therefore, the aim of the present study was to examine trace elements (iron, copper, zinc, and selenium) in murine liver tissue prepared by a RIPA buffer-based lyses method.Methods and resultsAfter centrifugation, lysates and pellets were obtained and trace elements were analyzed with TXRF in liver lysates. The results were compared to that obtained by a standard microwave-assisted acidic digestion with subsequent ICP-MS/MS analysis of the same liver tissue, liver lysates, and remaining pellets. In addition, trace element concentrations, determined in murine serum with both methods, were compared. For serum samples, both TXRF and ICP-MS/MS provide similar and highly correlating results. Furthermore, in liver lysate samples prepared with RIPA buffer, comparable trace element concentrations were measured by TXRF as with the standard digestion technique and ICP-MS/MS. Only marginal amounts of trace elements were detected in the pellets.ConclusionTaken together, the results obtained by the present study indicate that the RIPA buffer-based method is suitable for sample preparation for trace element analyses via TXRF, at least for the here investigated murine liver samples.     

Impact of Ficoll density gradient centrifugation on major and trace element concentrations in erythrocytes and blood plasma

ProjectFicoll density gradient centrifugation is widely used to separate cellular components of human blood. We evaluated the suitability to use erythrocytes and blood plasma obtained from Ficoll centrifugation for assessment of elemental concentrations.ProcedureWe determined 22 elements (from Li to U) in erythrocytes and blood plasma separated by direct or Ficoll density gradient centrifugation, using inductively coupled plasma mass spectrometry.ResultsCompared with erythrocytes and blood plasma separated by direct centrifugation, those separated by Ficoll had highly elevated iodine and Ba concentration, due to the contamination from the Ficoll-Paque medium, and about twice as high concentrations of Sr and Mo in erythrocytes. On the other hand, the concentrations of Ca in erythrocytes and plasma were markedly reduced by the Ficoll separation, to some extent also Li, Co, Cu, and U. The reduced concentrations were probably due to EDTA, a chelator present in the Ficoll medium. Arsenic concentrations seemed to be lowered by Ficoll, probably in a species-specific manner. The concentrations of Mg, P, S, K, Fe, Zn, Se, Rb, and Cs were not affected in the erythrocytes, but decreased in plasma. Concentrations of Mn, Cd, and Pb were not affected in erythrocytes, but in plasma affected by EDTA and/or pre-analytical contamination.ConclusionsFicoll separation changed the concentrations of Li, Ca, Co, Cu, As, Mo, I, Ba, and U in erythrocytes and blood plasma, Sr in erythrocytes, and Mg, P, S, K, Fe, Zn, Se, Rb and Cs in blood plasma, to an extent that will invalidate evaluation of deficiencies or excess intakes.     

Studies on some trace and minor elements in blood

Blood is one of the widely used specimens for biological trace element research because of its biological significance and ease of sampling. We have conducted a study of the blood of the Kalpakkam township population for trace and minor elements. For this purpose, analytical methods have been developed and standardized in our laboratory for the elemental analysis of blood plasma and red cells. Inductively coupled plasma-mass spectrometry (ICP-MS), a relatively new technique, has been applied for the analysis of trace elements. Details regarding spectral interference and matrix interference encountered in the analysis of blood and the methods of correcting them have been discussed. Flame atomic absorption spectrometry (AAS)/atomic emission spectrometry (AES) has been applied for the determination of minor elements. Precision and accuracy of these methods have also been discussed.     

Use of dried blood spots and inductively coupled plasma mass spectrometry for multi-element determination in blood

The paper describes the development of an inductively coupled plasma mass spectrometry (ICP MS) method for multitrace element determination in dried blood spots (DBSs). The analytical conditions were optimized using Seronorm™ L-3 and L-1 Certified Reference Materials. The best results were obtained by sampling blood drops on a decontaminated PVDF filter membrane. After drying under metal-free conditions, the DBSs underwent acidic digestion and were analyzed with ICP MS. The method was then validated for As, Cd, Cu, Pb, Mo, Se and Zn. Using a matrix-matched calibration curve, the recovery levels ranged from 96% to 117%. The repeatability and reproducibility were generally below 15%. Limits of quantification ranging from 0.5 to 50 μg/L. In order to investigate the analytical procedure under real sampling conditions, the results obtained from DBSs and liquid blood aliquots (less subject to contamination) from two adult subjects were compared.     

A preliminary study of trace elements in plasma protein by gel chromatography combined with SXRF

Fractions of plasma protein of male Kunming mice (body weight 24.2±0.3g), treated with Cisplatin i.p. injection in dose of 10mg/kg, were obtained by separation on Sephadex-G-50 columns, buffered with ammonium acetate to pH 5.7. The SXRF experiments were performed at the BEPC (Beijing Electron Positron Collider) synchrotron radiation facility. The elements (Pt, S, Ca, Fe, Ni, Cu, Zn, Se, Br and Sr) in the fraction of the plasma proteins (< 22KD) were assayed using highly sensitive SXRF. The relative concentrations of elements were calculated by a normalization of Compton scattering intensity around 22 keV, after the normalization for collecting time of X-ray spectrum and the counting of the ion chamber, and subtracting the contribution of the polycarbonate film used for supporting the samples. The determination could prove that the element Pt in plasma was bound with macro-molecularprotein. Cu and S were present in the fraction of the protein in mice treated with Cisplatin and exhibited an increase, the ratio of treated/control were 1.66±0.06 and 1.78±0.33 respectively, whereas Zn decreased to a ratio of 0.78±0.09. Our results are in agreement with others which showed that Cisplatin exposure leads to a marked loss of kidney copper, and a moderate rise in kidney zinc. However, this work mainly focussed on the implementation of this analytical procedure, but not on the results of the investigations of the effect of Cisplatin on trace elements in plasma protein.     

Content of trace elements and chromium speciation in Neem powder and tea infusions

Total concentrations of selected trace elements in Neem powder and in Neem tea were determined by inductively coupled plasma mass spectrometry (ICP-MS). The data revealed that despite high total concentrations of the potentially toxic elements Al and Ni in Neem powder, their amounts dissolved in Neem tea were low. Total concentrations of the other toxic elements Pb, As and Cd were also very low and do not represent a health hazard. In contrast, total concentrations of the essential elements Fe, Cu, Zn, Se Mo and Cr in Neem powder were high and also considerable in Neem tea. Consuming one cup of Neem tea (2 g per 200 mL of water) covers the recommended daily intakes for Cr and Se and represents an important source of Mo and Cu.Speciation analysis of Cr by high performance liquid chromatography (HPLC) coupled to ICP-MS with the use of enriched Cr isotopic tracers to follow species interconversions during the analytical procedure demonstrated that toxic Cr(VI) was not present either in Neem powder or in Neem tea. Its concentrations were below the limits of detection of the HPLC–ICP-MS procedure applied. The speciation analysis data confirmed that even Cr(VI) was added, it was rapidly reduced by the presence of antioxidants in Neem leaves. By the use of enriched Cr isotopic spike solutions it was also demonstrated that for obtaining reliable analytical data it is essential to apply the extraction procedures which prevent Cr species interconversions, or to correct for species transformation.     

单方中药马蹄香散剂和几种微生态制剂中氨基酸和微量元素含量的测定和比较

目的 测定马蹄香和微生态制剂中氨基酸和微量元素的含量,深入认识马蹄香和微生态制剂的特点.方法 应用国家标准GB/T 5009.124-2003高效液相法和应用日本岛津公司ICPS-1000Ⅱ型等离子体发射光谱仪测定马蹄香和微生态制剂中氨基酸和微量元素含量.结果 氨基酸含量在乳酸菌素片＞亿活＞马蹄香＞金双歧＞贝飞达＞思连康＞合生原＞妈咪爱.谷氨酸在所有制剂中含量均高,天冬氨酸在多数制剂中含量也高.而胱氨酸在所有制剂中含量均低或未能测出.元素钙、磷、镁和硫含量在马蹄香＞乳酸菌素片＞亿活＞思连康＞金双歧＞妈咪爱＞贝飞达＞合生原.马蹄香中微量元素含量较丰富.结论 马蹄香和不同的微生态制剂所含的氨基酸和微量元素各有特点,这对不同制剂的微量营养素的认识有特殊意义.     

微量元素对糖尿病大鼠糖脂代谢的影响

目的观察微量元素铬对糖尿病大鼠糖脂代谢的影响。方法选糖尿病大鼠经灌胃给予有机铬水溶液治疗12周后,分别观察口服有机铬200μg/d及400μg/d的糖尿病大鼠空腹血糖及血脂水平(血清总胆固醇、甘油三酯、低密度脂蛋白和高密度脂蛋白)。实验分为4组:1组为正常对照组;2组为铬200μg/d组;3组为铬400μg/d组;4组为糖尿病对照组。结果有机铬具有明显降低血糖、血清总胆固醇、低密度脂蛋白和甘油三酯及升高高密度脂蛋白的作用(P0.05~P0.01)。结论有机铬能明显改善糖尿病大鼠的糖脂代谢。     

Trace elements in coronary heart disease

Concentrations of 14 trace elements (Bi, Cd, Co, Cs, Cu, Hg, Mn, Pb, Rb, Sb, Sn, Sr, Tl, and Zn) were determined by inductively coupled plasma mass spectrometry (ICP-MS) in 120 whole-blood and 121 plasma samples of 56 patients with angiographically documented coronary heart disease (CHD). One serum and two wholeblood reference materials were analyzed for quality control. At baseline, patients had elevated Co plasma as well as diminished Cu blood concentrations compared to healthy adults. The Zn concentrations in whole blood were below or at the lower end of the normal range, but the concentrations in plasma were elevated. All other trace elements were within the normal concentration ranges for healthy adults. After initial investigations, patients were randomly assigned to an experimental group (N = 27) and to a usual care group (N = 29). Experimental group patients were prescribed a lifestyle program that included a low-fat diet and a weekly moderate exercise. Patients were examined at baseline, after 6 and 12 mo for clinical assessment and fasting venous blood samples. No significant time-course changes in concentrations of trace elements in blood and plasma during the clinical treatment in both groups of patients could be observed. The experimental group patients lost weight and had lower blood pressure after 12 mo compared to baseline. The interventional therapy reduced the need for further revascularization procedures.     

Speciation of trace elements in proteins in human and bovine serum by size exclusion chromatography and inductively coupled plasma-mass spectrometry with a magnetic sector mass spectrometer

 Proteins are separated by size exclusion chromatography while atomic ions from the inorganic elements are detected on-line by inductively coupled plasma-mass spectrometry. A double focusing mass analyzer provides very high sensitivity, low background, and sufficient spectral resolution to separate the atomic ions of interest from most polyatomic ions at the same nominal m/z value. The chromatograms show the distribution of the elements of interest between protein-bound and free fractions and provide the approximate molecular weights of those protein fractions that contain the elements monitored. The distribution of various elements, including V, Mo, Fe, Co, Mn, and lanthanides, in human or bovine serum samples are shown. Alkali metals and Tl are present primarily as free metal ions and are not bound to proteins. Inorganic elements spiked into the serum samples can be followed into various proteins. EDTA does not remove Fe, Pb, Sn, or Th from the proteins but does extract Mn from some proteins. Procedures for determining the effects of breaking disulfide linkages on the metal binding characteristics of proteins are also described. Received: 22 March 1999 / Accepted: 16 June 1999     

Effects of treating seed potatoes with trace elements on sprouting and microbial spoilage during storage under tropical conditions

Attempts were made to extend the storage life of seed potatoes by treating them with trace elements as antimicrobial and antisprouting agents. In tests to measure the growth of Fusarium oxysporum, and Erwinia carotovora pv. carotovora it was found to be decreased more by iron, copper and zinc than by boron, manganese and molybdenum. Dipping seed tubers in aqueous solutions of trace element salts decreased both sprouting and microbial spoilage during storage at ambient conditions. Field testing at the end of storage proved that treating seed potatoes with ferrous sulphate did not decrease the yield of tubers or increase their iron content. It is suggested that trace elements may be used to extend the storage life of seed potato tubers, in tropical conditions.     

Reliability of the ICP-AES for trace elements studies of biological materials

In order to investigate the reliability of the Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) for trace element analysis of biological materials, we have carried out extensive investigations on human plasma, using an Applied Research Laboratory’s ICP-AES. When we aspirated the untreated plasma into the spectrometer, we obtained unreliable and nonreproducible results. However, when we pretreated the plasma by wet digestion (to destroy all the organic material), we achieved reproducible and consistent results. It is, therefore, suggested that biological samples should be pretreated, preferably by wet digestion, before being aspirated into the ICP-AES for analysis.     

Assessment of the contamination from devices used for sampling and storage of whole blood and serum for element analysis

An assessment of potential contamination risk associated with devices routinely used in hospitals and clinical laboratories for sampling and storage of whole blood and serum was made by analysis of leachates from the devices. The devices checked were disposable stainless steel needles, different types of blood collection tubes; serum separation tubes, disposable plastic pipettes and plastic vials used for serum storage. Concentrations of about 70 elements in solution after leaching with 0.05 mol l(-1) HNO3 were determined by double focusing sector field inductively coupled plasma mass spectrometry (sector field ICP-MS). For the elements present in blood/serum at concentrations higher than 10 ng ml(-1) (Na, Ca, Mg, P, Fe, Br, Si, Zn, Cu, Rb, Se and I) contribution from devices was as a rule negligible (less than 1% of expected concentrations in the body fluids), but for the majority of trace and ultra-trace elements it may significantly affect or even prevent accurate determination. The highest trace element contribution was found to derive from commercially available blood collection and serum separation tubes. Apparent concentrations of Al, Ba, Th, rare earth, and some other elements resulting from contamination were higher than normal serum concentrations all types of tubes tested for.     

A SXRF method for determining the relative concentration of trace elements in plasma protein affected by cisplatin

This article presents an analytical method for the determination of the relative concentrations of trace elements in plasma protein by gel chromatography combined with SXRF (synchrotron radiation X-ray fluorescence). The fraction of plasma protein of male Kunming mice (body weight 24.2±0.3 g), treated with a cisplatin ip injection at a dose of 10 mg/kg, was obtained by the separation of a Sephadex G-50 column (buffered with ammonium acetate, pH 5.7). The SXRF experiments were performed at the Beijing Electron Positron Collider synchrotron radiation facility. The elements (Pt, S, Ca, Fe, Ni, Cu, Zn, Se, Br, and Sr) in the fraction of the plasma proteins (>22 kDa) were assayed using highly sensitive SXRF. The relative concentrations of elements were calculated by a normalization of Compton scattering intensity around 22 keV, after the normalization for the collection time of the X-ray spectrum and the counting of the ion chamber, and subtracting the contribution of the polycarbonate film for the supporting sample. The determination could prove that the element Pt in plasma was bound with macromolecular protein. Cu and S were present in the fraction of the protein in mice treated with cisplatin increase, and their ratios of treated/control were 1.66±0.06 and 1.78±0.33, respectively; Zn decreased to a ratio of 0.78±0.09. Our results are in agreement with others that cisplatin exposure leads to a marked loss of kidney copper and a moderate rise in kidney zinc. However, this article primarily describes one of the analytical methods used; it does not emphasize the results of the effect of cisplatin on trace elements in plasma protein.     

Biomonitoring of 37 trace elements in blood samples from inhabitants of northern Germany by ICP–MS

The trace elements Ag, As, Au, B, Ba, Be, Bi, Cd, Ce, Co, Cs, Cu, Ga, Hf, Hg, In, La, Mn, Mo, Ni, Pb, Pd, Rb, Rh, Ru, Sb, Se, Sn, Sr, Te, Th, Tl, U, V, W, Y and Zr were determined in 130 human blood samples from occupationally non-exposed volunteers living in the greater area of Bremen in northern Germany. The blood samples were collected in lithium heparin monovettes developed for trace metal determination and were analysed by inductively coupled plasma mass spectrometry (ICP–MS) with an octopole-based collision/reaction cell. For sample introduction into the ICP, the blood samples were diluted 1/10 (V/V) with a 0.1% Triton-X-100 and 0.5% (V/V) ammonia solution. The method validation of our developed routine method is described for all 37 elements and results about internal and external quality assurance are discussed. Information on exposure conditions of all human subjects were collected by questionnaire-based interviews, including smoking habits, seafood consumption and the type of dental alloys in the teeth. Mean values, geometric mean values, ranges and selected percentiles of all elemental concentrations in human blood are presented, which helps toxicologists and clinical chemists planning research about exposition to metals and health effects caused by exposition to metals.     

Molybdenum in human whole blood of adult residents of the Merida State (Venezuela)

The concentration of molybdenum was measured in whole blood samples of 418 (244 males and 174 females) apparently normal donors ranging in age from 18 to 27-years old and living in nine different locations in the Mérida State (Venezuela). The geometric mean concentration of molybdenum of 418 subjects was of 2.66+/-0.66 microgL(-1) (range: 1.20-4.80 microgL(-1)). The levels of molybdenum in whole blood samples found in this work were of 2.57+/-0.52 and 2.54+/-0.51 (range: 1.20-4.80 and 1.40-4.20) microgL(-1) for males and females, respectively. The data of the content molybdenum in whole blood had no statistical correlation with age, sex or height above the sea level of the sampling sites. However, there was a tendency to decrease the levels of the element in those sampling sites located in highlands (> or = 1900 m above the sea level). This variability may be due to the source of molybdenum from the soil to the food chain that has affected its levels in donors from these areas under study. The results of this study are compared with values previously reported for subjects studied in other populations.     

Effects of dexamethasone on trace elements and serum protein patterns following brain trauma in rats

The effect of dexamethasone (Dxm) on trace elements and serum protein patterns was investigated in male Sprague-Dawley rats subjected to brain trauma. After 6-or 24 h of the traumatic incident, the level of serum copper was significantly higher in the Dxm-treated rats, compared to controls (p<0.05). The corresponding levels of zinc and iron did not show significant differences. The zinc level returned to normal 24 h after trauma. After 6 and 24 h of trauma, the sodium dodecyl sulfate (SDS)-polyacrylamide gel patterns of serum proteins showed that a 41.6-kDa protein was significantly increased in the Dxm-treated animals. Two proteins weighing 26.6 kDa and 55.1 kDa did not show Dxm-induced changes. These results suggest that increases in the copper-zinc ratio and the changes of the 26.6-kDa, 41.6-kDa, and 55.1-kDa proteins might be a useful prognostic indicator for severe traumatic brain injury.     

Effects of anticoagulants and storage conditions on clinical oxylipid levels in human plasma

Metabolomics and lipidomics are of fundamental importance to personalized healthcare. Particularly the analysis of bioactive lipids is of relevance to a better understanding of various diseases. Within clinical routines, blood derived samples are widely used for diagnostic and research purposes. Hence, standardized and validated procedures for blood collection and storage are mandatory, in order to guarantee sample integrity and relevant study outcomes. We here investigated different plasma storage conditions and their effect on plasma fatty acid and oxylipid levels. Our data clearly indicate the importance of storage conditions for plasma lipidomic analysis. Storage at very low temperature (?80?°C) and the addition of methanol directly after sampling are the most important measures to avoid ex vivo synthesis of oxylipids. Furthermore, we identified critical analytes being affected under certain storage conditions. Finally, we carried out chiral analysis and found possible residual enzymatic activity to be one of the contributors to the ex vivo formation of oxylipids even at ?20?°C.     

Major and trace elements in whole blood of phlebotomized patients with porphyria cutanea tarda

Porphyria cutanea tarda (PCT) is a disorder of hem biosynthesis resulting from a decreased activity of the uroporphyrinogen decarboxylase enzyme. Hem precursors are accumulated in the blood, liver and skin. Inherited and acquired factors also contribute to the pathogenesis of PCT. Hem precursors and porphyrins are excreted with urine and faeces. Whole blood of 8 PCT patients and 6 volunteers of Caucasian origin were analysed. In addition to routine laboratory measurements, 19 elements (Al, B, Ba, Ca, Cd, Co, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, S, V, Zn) were determined by means of inductively coupled plasma optical emission spectrometry (ICP-OES). Mg, P and S concentrations in whole blood were decreased significantly (p<0.05), whereas Ba was increased in PCT patients compared to controls. Metabolic alterations are reflected in the correlation of parameters. Positive correlations were found between the element pairs of Zn-Al, Zn-Mg, Zn-Mn, B-S, Fe-Mg, K-P, Mg-Mn for PCT patients, whereas in the control group Al-Mn, Ca-Cu, Ca-Na, Cu-Mg, Fe-K, Mg-Na, Zn-P showed positive correlations.     

Influence of Cultivation Parameters on the Mineral Composition of Kiwi Fruit from Corsica

The effect of four cultivation parameters (postmaturity harvest date, storage period at 0 °C, and input of nitrogen and potassium fertilizers) on the mineral composition of kiwi fruit (Actinidia deliciosa var. H ayward) from Corsica were evaluated. The kiwi fruit were harvested on three dates at two‐week intervals and some fruit were stored for three and four months. The kiwi fruit orchard was fertilized with controlled levels of nitrogen (five levels) and potassium (three levels) during one growing season. The concentrations of 67 elements in kiwi fruit were measured using various analytical methods, such as flow injection spectrophotometry, flame atomic absorption spectrometry, flame atomic emission spectrometry, electrothermal atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry, and filtration. The main elements in kiwi fruit are K, N, Cl, P, and Si and, to a lesser amount, Ca, Mg, Na, and Fe. This study demonstrates a high degree of difference in the amount of 23 mineral elements depending on the harvest date, the time of storage, and the input of fertilizers.