Fico D, Margapoti E, Pennetta A, De Benedetto G E
Laboratorio di Spettrometria di Massa Analitica ed Isotopica, Dipartimento di Beni Culturali, Università del Salento, 73100 Lecce, Italy.
IBAM-CNR, Sede di Lecce, Via per Monteroni, 73100 Lecce, Italy.
J Anal Methods Chem. 2018 Apr 1;2018:6032084. doi: 10.1155/2018/6032084. eCollection 2018.
The chemical characterization of materials used in works of art is extremely useful for gaining a better knowledge of the artistic heritage and to guarantee its preservation. A derivatization GC/MS procedure for the identification of proteins in a microsample from painted works of art has been optimized. The amino acid fraction is derivatized using anhydrous dimethylformamide (DMF) as solvent instead of pyridine (Py), commonly used to facilitate the reaction. Although pyridine is often considered a silylation catalyst, there are many instances in which silylation reactions actually are slower in pyridine than other solvents. In addition, pyridine also may have other undesirable effects such as the promotion of secondary products and other chromatographic anomalies. Using DMF, the formation of artifacts is limited and the derivatization yield of hydrophilic amino acids such as proline and hydroxyproline has improved, thus making the identification of organic paint media more straightforward. The method has been validated and successfully applied to identify the binder of the sample taken from the pictorial cycle of the 12th century monastery of Santa Maria delle Cerrate (Lecce, Italy), thus highlighting the use of eggs as a binding medium.
艺术品所用材料的化学表征对于更深入了解艺术遗产和确保其保存极为有用。一种用于鉴定绘画艺术品微量样品中蛋白质的衍生化气相色谱/质谱法已得到优化。氨基酸部分使用无水二甲基甲酰胺（DMF）作为溶剂进行衍生化，而不是常用的吡啶（Py），吡啶常用于促进反应。尽管吡啶常被视为硅烷化催化剂，但在许多情况下，硅烷化反应在吡啶中的速度实际上比在其他溶剂中慢。此外，吡啶还可能有其他不良影响，如促进副产物生成和其他色谱异常。使用DMF时，假象的形成受到限制，脯氨酸和羟脯氨酸等亲水性氨基酸的衍生化产率有所提高，从而使有机绘画媒介的鉴定更加直接。该方法已得到验证，并成功应用于鉴定取自意大利莱切圣玛丽亚·德尔·塞拉特12世纪修道院绘画系列样品的粘合剂，从而突出了鸡蛋作为粘结媒介的使用。
