Hourly measurement of particulate concentrations with streaker samplers and optical methods

We have studied the possibility of continuous particulate monitoring, by an optical system, on the filters of a two-stage streaker sampler. The streaker deposits, collected for PIXE analysis, have been examined off-line by measuring the attenuation of a light beam. The optical analysis provides, in a few minutes, an estimate of hourly total mass concentrations, over a one week period, for both stages, very useful as a selection for further PIXE irradiation. We describe the set-up and the calibration procedures, where PIXE plays a fundamental role in resolving different aerosol compositions and in validating the prototype performance. The results obtained over 2 weeks of operation and the comparison with the aerosol component determined via PIXE analysis, are also discussed.     

A new analysis chamber with a rotating target holder for total-sample PIXE analysis of aerosol deposits collected in Berner impactors

We describe an external PIXE analysis chamber provided with means for determining the total amount of aerosol material sampled in Berner impactors. The deposits are concentrated in equally spaced small spots along a circle with a diameter of 50 mm. To pass the whole distribution of material through the probing proton beam, the thin backing film is mounted on a rotatable target holder. Driven by a motor, the holder is rotating at a speed of typically 1/min. Depending on the total duration of the analysis, the sample is rotated 3–10 times through the beam. For high sample throughput the analysis chamber is coupled to a helium-backfilled transfer box in which six holders can be stored, at the same pressure as in the analysis chamber. Loading of the transfer box, with a minimum loss of helium, is accomplished by activating load locks on either side of the box. The first experience gained with aerosol samples as well as with dedicated reference standards is discussed with particular reference to the uniformity of aerosol deposits.     

Elemental and mineral characterisation of Coastal Antarctic Aerosols in snow using PIXE and SEM-EDAX

The chemical constituents of snow from a 3 m pit sampled at a coastal Antarctic site were characterised by means of PIXE and SEM-EDAX. Oxygen isotope dating revealed that the pit spanned an 8-year period, from 1986 to 1994. Concentrations measured by PIXE ranged from less than 1 ng g⁻¹ of H₂O for Cu, and Zn to several tens of ng g⁻¹ for Si, S and Cl. The major elements found were Si, S, Al, and Na, which contributed more than 75% of the element loading. Snow layers with elevated Cl concentration were regularly found along the pit. The mineralogy of the insoluble particles determined by SEM-EDAX analyses showed that quartz, plagioclase and clays were the prevalent minerals. The proportion of each element in the insoluble phase was comparable with that previously found in similar studies.     

PIXE analysis of airborne particulate matter from Monterrey, Mexico. A first survey

A first survey of elemental contents in airborne particulate matter from Monterrey, Nuevo León, Mexico, was performed using PIXE. This second largest industrial city is located 715 km north of Mexico City, and counts with a population of nearly three million inhabitants in its conurbation. Air pollution in the place comes from a great variety of industries ranging from iron smelters to furniture manufacturing, as well as from fuel combustion in vehicles and industries. This study presents results of elemental contents in airborne particulate matter in two particle size fractions: PM_2.5 and PM₁₅. The samples were collected during five weeks on working days, Monday–Friday, from 9 December 1996 to 14 January 1997. Two samples a day were collected, 12 h each, night-time and day-time. These first results show local pollution as typical from a large urban area in conjunction with an active industry. Thirteen elements were consistently detected in most of the samples and some episodes due to both industrial and human activities were identified. A general discussion about the results obtained is presented.     

用质子激发X射线分析方法进行人发微量元素的分析研究

一、序言 质子激发X射线分析方法是瑞典人约翰逊在1970年首先提出来的。由于它具有灵敏度高、取样少、无损伤、快速、适用范围广等特点,使它在十余年中在生物医学、环境科学、地质、冶金、考古学和法学等领域得到了广泛的应用。我们应用质子激发X射线分析方法分析了人发中的微量元素。     

Chemical speciation of chlorine in particulate matter by wavelength-dispersive PIXE technique

Chemical speciation of chlorine (Cl) in atmospheric particulate matter (APM) was performed by using a wavelength-dispersive PIXE spectrograph based on high-resolution measurement of Cl-Kβ emission. Samples of atmospheric particles were size-fractioned and collected by a cascade impactor at an urban area in Tokyo. The target position with respect to the spectrograph was precisely adjusted by a 2D laser displacement sensor to achieve high detection efficiency. The samples were irradiated with 2 MeV protons from a tandem electrostatic accelerator. The beam current was 300-500 nA. During the irradiation, the target was cooled by liquid nitrogen to avoid the evaporation of volatile Cl compounds. The measured spectra for the NaCl standard samples clearly showed the Cl-Kβ series composed of the Kβ₁ and the satellite Kβ_x, Kβ₅ lines. From the measured X-ray yields, it was found that the chemical speciation of samples with Cl concentrations as low as ≈1% is possible by this method. The Cl-Kβ series were also successfully observed in the case of APM samples with particle sizes of 11.0-2.1 μm. The spectra shapes of the NaCl standard samples and an APM sample were slightly different from each other, because of some possible mixing of non-sea salt component in the APM sample.     

PIXE analysis of airborne particulate matter from Xalostoc, Mexico: winter to summer comparison

A study of elemental contents in airborne particulate matter from the industrial city of Xalostoc, Estado de México, was performed using PIXE. The place has a great variety of industries, it is a heavily populated, and it is a part of Mexico City's conurbation, thus contributing significantly to its atmospheric pollution. At present, there is few information available about elemental contents in airborne particulate matter from that region. In this study, two sets of samples of airborne particulate matter were collected daily during periods of four weeks in summer 1996 and winter 1997; two samples a day, 12 h each, night-time and day-time. Results revealed important information about elemental contents in airborne particulate matter from that area, especially in the respirable fraction PM_2.5. Comparison of night and day figures showed the presence of some elements such as Cu, Zn, and Pb, attributed, as it was expected, to uninterrupted industrial processes. Appearance of some other elements was more consistent only in either day-time or night-time due to diurnal or nocturnal industrial activities, or produced by human activities such as fuel combustion of automotive vehicles. Comparison of winter to summer results showed some other important features such as higher concentrations of pollutants in winter, because of the dry and cold weather, while summer samples exhibited lower concentrations mainly due to the presence of rain showers.     

PIXE analysis of biological bodies in Uranouchi bay

We have investigated shellfish called Japanese littleneck clam (Ruditapes philippinarum) which were collected from Uranouchi bay (Kochi, Japan) for analysis of elemental concentration by Particle Induced X-ray Emission (PIXE). A 4 MeV He⁺⁺ ion beam was used to analyze shellfish in the ion beam laboratory of Kochi University of Technology (Japan). In the present study, shellfish have been chosen as a representative of the biological bodies in the Uranouchi bay. The concentration of heavy metals in shellfish has been quantified and the results are compared with those obtained by analyzing Market shellfish. Analyzing shellfish collected from three different places in the bay Cu, Zn, Br, Sr and Zr are detected as heavy metals. Our results suggest that in comparison with Market shellfish the Uranouchi bay shellfish contain more heavy metals.     

Golden glazes analysis by PIGE and PIXE techniques

We present the analysis performed on the chemical composition of two golden glazes available in the market using the PIGE and PIXE techniques at the ITN ion beam laboratory. The analysis of the light elements was performed using the Emitted Radiation Yield Analysis (ERYA) code, a standard-free method for PIGE analysis on thick samples. The results were compared to those obtained on an old glaze. Consistently high concentrations of lead and sodium were found in all analyzed golden glazes. The analysis of the samples pointed to Mo and Co as the specific elements responsible of the gold colour at the desired temperature, and allowed Portuguese ceramists to produce a golden glaze at 997 °C. Optical reflection spectra of the glazes are given, showing that the produced glaze has a spectrum similar to the old glaze. Also, in order to help the ceramists, the unknown compositions of four different types of frits (one of the components of glazes) were analysed.     

Quantitative analysis of a metalloprotein compositional stoichiometry with PIXE and PESA

An absolute measurement of the heavy element concentrations in a dried sample of aqueous protein solution has been combined with the absolute measurement of protein molecular concentration in the same sample. The ratio of these two measurements yields the metal-to-protein compositional stoichiometry of the metalloprotein. This combination of two Ion Beam Analysis techniques (Particle-Induced X-ray Emission and Proton Elastic Scattering Analysis) allows quantitative assessment of the metal atom to protein ratio in metalloproteins without direct measurement of sulfur atoms within the protein for the first time. While these results only demonstrate success with a single well-known metalloprotein, this combination of measurement ratios holds promise for future Ion Beam Analysis studies of metalloproteins.     

Non-destructive analysis and appraisal of ancient Chinese porcelain by PIXE

This paper reports the results of the PIXE analysis on ancient Chinese blue and white porcelain fired at Kuan Kiln (Jingdezhen, Jiangxi province) during 13–19th century. The major, minor and trace element of porcelain body, white glaze and blue glaze were determined by PIXE. In this paper the chemical compositions of porcelain body, white glaze and blue glaze measured from Yuan (AD 1206–1368), Ming (AD 1368–1644) and Qing (AD 1616–1911) blue and white porcelain are present. The cobalt blue pigment used in Yuan, Ming and Qing are also discussed.     

In situ analysis of human teeth by external PIXE

The elemental profiles of the enamel, cementum and caries of human teeth were analysed by the external proton induced X-ray emission studies. Ten elements namely P, Ca, V, Mn, Fe, Cu, Zn, As, Sr and Pb were estimated in the present study. P and Ca were found to be the major elements whereas all other elements were found in trace level. It was observed that the respective concentrations of elements namely P, Ca, Fe, Zn and Pb in enamel are more than those in cementum. Concentration of P ranged between 6.37% and 25% whereas Ca ranged between 12.94% and 43.36%.     

Elemental analysis of agricultural soil samples by particle induced X-ray emission (PIXE) technique

In agriculture, elements essential to vital processes are also called nutrients. A suitable and reliable particle induced X-ray emission (PIXE) methodology for content determination of essential nutrients in soil samples was developed and its effectiveness proved. The PIXE method is applied to intermediate thickness samples, whose mass per area unit are smaller than 1 μg/cm². Precision and accuracy of the method was estimated after repeated measurements of a single reference material: CRM PACS-2 (estuarine sediment) with a matrix quite similar to the soil samples measured. This paper reports the results of elemental measurements in soil samples. A discussion of agricultural soil sample preparation for PIXE analysis is also presented.     

Trace element analysis of blood samples from mentally challenged children by PIXE

The accelerator based ion beam analysis method of proton induced X-ray emission (PIXE) has been used for analysing up to 14 elements in the blood serum of patients, collected from rehabilitation centres for the mentally retarded and from Medical College Hospital, Coimbatore, Tamil Nadu, India. The experimental subjects of the different groups displayed significant variations in their levels of certain trace elements such as zinc, iron, copper, phosphorus, chlorine, and rubidium. The results are compared with those of healthy control subjects and are discussed in detail in this paper. Hence, PIXE as a method of trace element analysis can be used to determine trace element content in mentally challenged patients.     

Analysis of lichen thin sections by PIXE and STIM using a proton microprobe

In order to better understand the distribution pattern of mineral elements in lichen tissues, thin sections (15 μm) of the foliose, vagrant soil lichen Xanthoparmelia chlorochroa were examined using proton microprobe Particle induced X-ray emission (PIXE). This technique was used to make two-dimensional scans, with 5 μm resolution, across tissue cross sections of the test species. Element maps for Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, and As have been prepared. Several elements are strongly localized in the element maps. PIXE data are complimented with STIM, light micrographs, and SEM images. Preliminary data suggest that nuclear microprobe techniques may be useful in elucidating element absorption and transport mechanisms in lichens.     

股骨头松质骨中无机元素的PIXE分析

使用质子激发Ｘ射线荧光分析技术测定了５例正常人和７例股骨颈骨折患者股骨头松质骨中无机元素谱的分布。详细介绍了骨样品处理技术，建立了正确测定骨骼微量元素的定量方法。结果表明在对照组中元素Ｐ、Ｃａ、Ｆｅ、Ｃｕ、Ｓｒ的含量高于病变组，统计检验表明有显著意义，而元素Ｓ、Ｋ、Ｍｎ、Ｚｎ在两组间无显著差异。对Ｃａ、Ｐ、Ｓｒ、Ｃｕ等无机元素的生理功能进行了初步的讨论。     

癌和正常组织细胞中钾元素的PIXE测定

应用质子激发Ｘ荧光技术（ＰＩＸＥ）对胃癌、肠癌、肺癌和癌细胞株的钾元素进行了测定，结果发现组织中的钾浓度明显高于正常组织，提示癌细胞高钾可能与细胞分裂速度有关。