Point analysis providing chemical composition of layers and bulk

3 Point analysis providing chemical composition of layers and bulk 

Mossbauer spectroscopy is a selective tool for the quantitative analysis and spe-ciation of a very limited number of elements. It has been mainly used to study iron compounds—e.g., ceramics, as it gives valuable information about iron-bearing oxide and silicate minerals. This technique has been applied to the identification of the provenance of clay and used raw materials—the manufacturing method employed in pottery and, to a lesser extent, to the characterization of pigments and weathering crusts formed on stone monuments [23]. 

Neutron activation analysis (NAA), based on the interaction of the object material with fast neutrons, has been used in the identification and determination of the content of elements present in pigments, coins and alloys, stone, glass, and pottery [26]. Multi-elemental analysis (about 20 elements) can be performed on small samples off less than 5 mg, with sensitivities in the ppm range. The requirement of a nuclear reactor, the handling of radioactive materials, and the time-consuming procedures required for preparing the samples are the main drawbacks of this technique. 

Proton activation analysis (PAA) provides chemical composition of the materials at a depth of 300-500 pm under the irradiated surface. This technique has been used in the study of metallic objects such as ancient coins [27]. 

Measurement of pH is a potentiometric technique frequently used for measuring the degree of the deterioration of materials that are subjected to natural aging. The determination of pH levels is commonly carried out on ethnographic objects manufactured with parchment or leather, and it is especially relevant in altered paper due to the formation of acidic compounds from the decomposition of the woodpulps and other raw materials, which can induce the hydrolysis of the cellulose and then decrease the resistance and mechanical properties of the document [29]. 

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