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Introduction: Paper is the most important material of the printing industry and is being improved due to the increasing needs of industry. The most important process to improve the optical and physical properties of paper is the surface coating. Paper has a smoother and opaquer surface with surface coating. In addition, brightness, whiteness, and yellowness values are improved with surface coating. Ultraviolet (UV) light in sunlight causes changes in the structure of the paper and coating chemicals and accordingly causes yellowing. Para-amino benzoic acid (PABA), due to its chemical structure, is a UV-blocking agent used in sunscreen creams. Methods: The effect of PABA on paper gloss, yellowness, and lightfastness values was investigated by adding it into the surface coating formulation. For this purpose, coating formulations were prepared with cationic starch and 3%, 5%, and 7% PABA; coatings were applied to the paper according to laboratory condition standards. Coated papers were printed with an IGT-C1 lab-type offset printability device with magenta ink. The printed papers were then exposed to a light fastness test with Solarbox. The color, brightness, and yellowness values of all samples before and after lightfastness were measured with an X-Rite spectrophotometer. The gloss of coated and printed paper sample values was measured with a BYK-Gardner glossmeter. Results: The gloss values of paper to which PABA was added, increased; however, it was determined that these gloss values decreased after the lightfastness test. Conclusions: PABA-added cationic starch coatings are more affected by UV light than cationic starch coatings.

Selected organic compounds commonly occurring in plant and animal tissues have been chromatographed on glass fiber, paraffin-coated and untreated cellulose paper in a number of different solvent systems. The RF values of these compounds represent new additions to the literature in the solvent systems studied.

Screening programs for late-onset, biotin-responsive, multiple carboxylase deficiency (LMCD) detect colormetrically the presence of biotinidase activity in dried samples of whole-blood spotted on filter-papers as used in the neonatal screening of phenylketonuria. A sensitive and stable qualitative technique is described using 10 microliter of serum that avoids problems associated with poor sample collection, improper drying of blood-spots and transient color development. The modified assay is timely and suitable for the clinical laboratory not involved in mass screening programs.