engleski

Sample preparation for characterization of guitar strings

Skin allergy occurs frequently in musician population: 22% of musicians have skin problems and 19% of them have skin dermatitis. The most problematic metal is nickel since 20% of female and 6% of male population is allergic to it. Therefore the EU Nickel Directive The Dangerous Substances and Preparations (Nickel Safety) Regulations limits the extractable nickel in everyday metal items that are coming into direct and prolonged contact with the skin to the amount of 0.5 μ g Ni/cm2/week. Unfortunately, the existing testing procedures are not appropriate for the musical string analysis due to the relative mild testing conditions. Therefore, in this work we emphasize the importance of careful sample preparation for proper monitoring of nickel and other allergenic metals on surface of nickel plated steel strings, since those can be extracted by playing the guitar. Since the nickel in guitar strings may be present in the steel as alloying element, or as the coating on strings, sample preparation included three separate processes: for monitoring of extractable metal ions in artificial sweat solutions, for chemical analysis of bulk string samples and for analysis of metal distribution through sample cross section. Firstly, the samples of strings were immersed in artificial sweat solution at 37 °C according to EN 1811:1995 for monitoring of extractable metal ions. Secondly, the dissolution in nitric acid was performed for chemical analysis of string samples. All the analyses were performed by inductively coupled plasma - optical emission spectrometry and flame absorption spectrometry. In order to understand the metal elution process in artificial sweat solution, it is important to know the distribution of metals through sample. Therefore, scanning electron microscope equipped with EDS detector was applied. Prior to SEM-EDS analysis, samples were cut, embedded in resin DuroFix-2 Kit, grounded and then polished up to 1 μ m with a diamond paste until a mirror-like surface was achieved.

sample preparation; metal; guitar strings; allergy; SEM-EDS; AAS; ICP-OES;

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