Retinal+retinol+retinoic acid:MCnt:Pt:XXX:Qn
retinal+retinol+retinoic acid:mcnt:pt:xxx:qn
Retinal+retinol+retinoic acid:Mass Content:To identify measures at a point in time:Not specified:Quantitative
retinal+retinol+retinoic acid:mass content:to identify measures at a point in time:not specified:quantitative