The basic concept of a sample Preparation method is to convert a real matrix into a sample in a format that is suitable for analysis. Some gaseous, liquid, and volatile solid samples are suitable for direct injection to gas chromatography instrument. But most samples are not ready to introduce directly into the column of GC. such as removal of serious interferences from the sample, increase of analyte concentration, convert the analyte into a more suitable form to detect and determine, using smaller initial sample sizes and finally achieving higher selectivity. This article discusses various types of analyte extraction, cleanup and concentration. Extraction methods can include classic techniques such as purge and trap, static headspace extraction, and liquid-liquid extraction to newer techniques such as solid phase microextraction, membrane extraction, single drop microextraction and superheated water extraction.

Information on the size dependence of the concentration of pollutants in fine-grained residues is required for the design of classification processes for their processing. For such an analysis, the samples have to be classified prior to chemical analysis. Depending on the particle size range of the residue, a classification method has to be selected. For very fine material, air classification is a suitable method. In this work, the results of the classification of fly ash from a biomass combustion plant with an air classifier are discussed with respect to the observed sample contamination. The chemical analysis of the produced size classes for heavy metals yielded unexpected results. For most heavy metals, the mass balance resulted in a recovery rate of about 100 %; however, for Cr and Ni, the recovery rate was way above 100 %. A more detailed analysis of the data revealed that the ratio of the excess of Cr to Ni in the fly ash was nearly the same as the ratio of Cr to Ni in the material of parts of the classifier. Therefore, erosion of some material from the classifier can be assumed to have caused the contamination of the sample. For the classification of samples, which have to be analysed for Cr and Ni, a classifier has to be used which is made of a material other than stainless steel.

Introduction: Perpetration of samples is one of the most important stages needed for trace residue analysis of biological specimens when human exposure assessment is required. The samples Preparation process makes the analyte get more purified and enriched as well as more compatible to the analysis instrument systems. The present study has concentrated on a systematic review of different articles published regarding the sample Preparation methodologies of human biological samples. Material and Methods: In this systematic review, all articles related to the development of sample Preparation for trace residue analysis of heavy metals in occupational biological samples published in English during 2009-2019, were considered. To meet the desired objective of the current study and facilitate the related articles on physiochemical sample Preparation methods accessibility combined keywords of Mesh and non-Mesh, without any limitation in the type of studies, the Pubmed, Web of Science, and Scopus were considered to be searched. Noteworthy, in this study, only the articles related to the workers’ biological samples were reviewed. Results: Based on the obtained results, after reviewing of the keywords trough websites, 2964 articles were identified. Then, the redundant papers were removed and59 articles were remained, based on their titles and abstracts, . After detailed review of selected articles, regarding the study criteria, 8 articles were selected for the final systematic review. Five articles out of 8, (62. 5%) were allocated to the development of sample Preparation for mercury in biological samples. It is worth mentioning that the majority of biological samples were regarded to the urine samples (75%) in the current study. Based on the obtained results, Solid Phase Extraction (SPE), applied in 37. 5% of studies, was a popular method used in sample Preparation. Conclusion: The development of sample Preparation approaches indicates a great promise for specified methods with low costs and less extraction time when separating different heavy metals from complex matrices. These sample Preparation and preconcentration techniques ease the analyses processes and provide the quantitative recoveries, higher sensitivity, and lower detection limits.

Size, shape, volume fraction and distribution of embedded γ / phase in γ phase has direct effect on strength of INCONEL alloy. Microstructure parameters of INCONEL phases are quantified from microstructure images using transmission electron microscopy (TEM). Different TEM sample Preparation techniques were used to study INCONEL 738 alloy microstructure for transmission electron microscopy (TEM). The INCONEL 738 was first cut into a 1 × 1 cm slice with 600 μ m thickness with diamond wire cut. INCONEL sample was mounted by wax (M135), after initial grinding and polishing. The molded INCONEL sample was further polished by different grit size SiC paper to reduce the thickness below 80 micron. At this stage, 3 mm discs were cut from the thin slice of INCONEL alloy by mechanical punch machine. The 3 mm discs of INCONEL alloy were used for TEM sample Preparation. Three methods of electro-jet polishing, ion milling and micro control dimpling were employed to prepare transparent TEM sample to observe the surface microstructure details of INCONEL 738 alloy. Electro-jet polishing TEM sample Preparation technique could reveal microstructure details of INCONEL alloy γ and γ / phases using 42% H3PO4, 34% H2SO4, 24% H2O electrolyte at about – 400C bath temperature and applied voltage of 30 V.