Paper analysis

The reagents used for filter paper analysis are the same as for plasma acylcarnitine analysis except for the internal standard/extraction solution, which is prepared using methanol as opposed to acetonitrile. 

Infrared microspectroscopy is used in the pulp and paper industry73 for compositional analysis of pulp, wet end and size press chemical components in paper contaminants, additives and cellulose, and inks. Wilkinson et al.74 studied ink-paper interactions to discern changing ink properties when applied to paper. In this work, the authors employed synchrotron-based reflectance infrared microspectroscopy as a rapid, direct and nondestructive analysis approach for the study of inks on paper. The authors of this chapter expect infrared imaging to gain popularity as a technique for paper analysis. 

Both the ink and paper of a document possess potential value in detecting possible fraud through the use of scientific techniques. Within the Bureau of ATF, the Identification Branch of the Laboratory met the challenge placed on its chemists by the pressing needs of the many enforcement groups for this scientific type of work. These chemists discovered that the application of well established and proven scientific methods of ink analysis ( 1) in conjunction with a well maintained up-to-date standard ink library could lead to the identification and dating of writing inks (2). This accomplishment has proven to be extremely valuable whenever the date of preparation of a document is questioned. Paper analysis, which can provide valuable information in these efforts ( 3), will not be dealt with in this article. 

Analysis revealed that ink prepared from the same formulation was used on each of the seven pages. This test, together with the findings from paper analysis and watermark examination conducted on the documents, helped to substantiate the authenticity of the questioned document. The ink testimony was accepted by the court as valid and persuasive and the examinations conducted by the Bureau of ATF Identification Branch were held in the balance by the court even though a large sum was spent on defense expert work and testimony. 

Another application of Py-GC in paper analysis has been the determination of wet strength polyamide-epichlorhydrin (PAE) resins [89]. 

The laboratory fusing method was developed on basis of procedures devised by L. Ho, IBM, Boulder. J. Witt and F. Rodgers, IBM, Tucson provided chemical paper analysis and fuse quality measurements. 

Turning our attention to the circuit shown in Figure 5-6, we should be clear that this circuit doesn t really work We know from our discussions in Chapter 1 that we can never hope to achieve a steady state without at least an output capacitor present — to charge up and thereby help stabilize the voltseconds across the inductor. So this circuit is clearly an idealization — it only helps us to perform a paper-analysis of a particular switching transition. 

Symington, J., Green, M. and Brack-mann, K. (1981) Immunoautoradio-graphic detection of proteins after electrophoretic transfer from gels to diazo-paper analysis of adenovirus encoded proteins. Proc. Natl Acad. Sci. U.S.A., 78, 177-181. 

Fleischmann, M. and Pons, S. (1992) Some comments on the paper analysis of experiments on calorimetry of lithium deuteroxide/heavy water electrochemical cells . Journal of Electroana-lytical Chemistry, 332, 33. 

Microscopy is a powerful tool for paper analysis and can be used to identify fiber types and particulates. Staining techniques such as Grafs C stain can help differentiate pulping methods and fiber types. Cotton fibers have a distinctive appearance under polarized light and are easily recognized. Fibers can be counted in order to estimate the cotton rag content of... 

Table 14.1 Hypothetical Paper Analysis (n = 1 for each sample) 1...

For example, consider the following possibility The observed variation in elemental concentrations shown in Table 14.1 may exceed the normal roll-to-roll variation within a plant, but not the normal batch-to-batch variation. Thus, the paper could have come from the same plant, but have been produced days or weeks apart. This hypothetical situation illustrates the caveats associated with low- and trace-level analyses of evidence. The lower the concentrations studied, the more likely it is that there will be greater variation. The same phenomenon occurs near the LOQ of a calibration curve. The lower the concentration, the higher will be the %RSD of replicates. Thus, any differences seen in the present paper analysis example must be interpreted in light of a complete understanding of what constitutes normal variations, no matter what the source of those variations. When uncertainties are known and taken into account (Table 14.2), interpretation is reliable and quantifiable. In this example, the strontium concentrations are telling The variation indicates that the differences observed between the questioned and known samples cannot be attributed to expected variations, even from month to month. Does this mean that the two papers are different At this point, our... 

Protein adrenocorticotropic hormone preparations from sheep have been shown to be of multiple nature when subjected to zone electrophoresis, both in filter paper (Li, 1952) and in starch (Porath, personal communication). Only one of the zones possessed biological activity. Partial peptic and hydrochloric acid hydrolyzates of the active zone also gave several zones. As the active component was strongly adsorbed in filter paper, analysis in a starch medium was preferred. The active zone from this possessed very high activities but was still not a single defined substance. 

SFE is a good procedure to extract the contaminants present in paper samples. This extraction technique, easy to use with minimmn handling and time, has been shown to be very efficient for paper analysis. 

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