Cinnamic acid, 3,5-dimethoxy-4-hydroxy

For PMMA/additive dissolutions, it was not possible to identify any additive characteristic mass peaks, either by direct laser desorption or with matrix-assistance (dithranol, DHBA or sinapinic acid, 4-hydroxy-3,5-dimethoxy-cinnamic acid). This has again been ascribed to very strong interaction between PMMA and additives, which suppresses desorption of additive molecules. Also, partial depolymerisation of pho-tolytically labile PMMA by laser irradiation may play a role, which leads to saturation of the detector by PMMA fragment-ions and disappearance of additive mass peaks below noise level. Meyer-Dulheuer [55] has also reported MALDI-TOFMS analysis of a coating/2-ethylhexyldiphenylphosphate sample. Quantitative determination of the additives by means of MALDI-ToFMS proved impossible. Possibly the development of reproducible (automated) sample handling procedures or thin films might overcome this problem. 

The most common cinnamic acids are caffeic (3,4-dihydroxycinnamic acid), ferulic (3-methoxy-4-hydroxy), sinapic (3,5-dimethoxy-4-hydroxy) and p-coumaric (4-hydroxy) acid, Table 4 [13]. 

The most commonly used matrices for synthetic polymers are DHB (2,5-dihydroxybenzoic acid), HABA (2,(-4-hydroxyphenylazo)benzoic acid), lAA (3-j3-indoleacrylc acid), dithranol (1,8,9-trihydroxyanthracene), sinapinic acid (3,5-dimethoxy-4-hydroxy cinnamic acid), all trans-retinoic acid, and 5-chlorosalicylic acid. Exhaustive lists of useful matrices are available in the literature. ... 

SIA (4-Hydroxy-3,5-Dimethoxy-Cinnamic Acid) (Fig. 63.2) is a phenylpropanoid compound found in various herbal materials and high-bran cereals. It has been reported that sinapic acid has antioxidant efficacy as a metal chelator due to the orientation of functional groups. Administration of sinapic acid exhibited significant reversal of arsenic-induced toxicity in hepatic tissue [68]. 

Qiao HY, Dahiya JP, Classen HL. 2008. Nutritional and physiological effects of dietary sinapic acid (4-hydroxy-3,5-dimethoxy-cinnamic acid) in broiler chickens and its metabolism in the digestive tract. Poultry Science, 87(4) 719-726. 

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