ABSTRACT
This study aimed to assess the measurement uncertainty of a new method for determination of allura redin food by high performance liquid chromatography (HPLC).The uncertainty of mathematical model of allura red is based on Europe for Analytical Chemistry(EURACHEM) guidelines.The sources and components of uncertainty were calculated,including recovery,working solution,sample mass,final volume,response of standard solution,response of sample solution.The expanded uncertainty was 0.0024 (k=2).Uncertainty of working solution was the most significant factor contributing to the total uncertainty,accounting for 86.2％.The uncertainty of volume accounted for the minimum at 0.025％.The developed method is simple and accurate,which can be used for the determination of allura redin puffed samples.
ABSTRACT
This study aimed to assess the measurement uncertainty of a new method for determination of allura redin food by high performance liquid chromatography (HPLC).The uncertainty of mathematical model of allura red is based on Europe for Analytical Chemistry(EURACHEM) guidelines.The sources and components of uncertainty were calculated,including recovery,working solution,sample mass,final volume,response of standard solution,response of sample solution.The expanded uncertainty was 0.0024 (k=2).Uncertainty of working solution was the most significant factor contributing to the total uncertainty,accounting for 86.2％.The uncertainty of volume accounted for the minimum at 0.025％.The developed method is simple and accurate,which can be used for the determination of allura redin puffed samples.
ABSTRACT
<p><b>BACKGROUND</b>Solar ultraviolet (UV) irradiation induces the production of matrix metalloproteinases (MMPs) by activating cellular signalling transduction pathways. MMPs are responsible for the degradation and/or inhibition of synthesis of collagenous extracellular matrix in connective tissues. We mimicked the action of environmental ultraviolet on skin and investigated the effects of UVB-irradiated human keratinocytes HaCaT and IL-1alpha on mitogen activated protein (MAP) kinase activation, c-Jun and c-Fos (AP-1 is composed of Jun and Fos proteins) mRNA expression and MMP-1 production in UVA-irradiated dermal fibroblasts.</p><p><b>METHODS</b>Following UVA irradiation, the culture medium of fibroblasts was replaced by culture medium from UVB-irradiated HaCaT, or replaced by the complete culture medium with interleukin (IL)-1alpha. MAP kinase activity expression in fibroblasts was detected by Western blot. c-Jun and c-Fos mRNA expressions were determined by reverse transcriptional polymerase chain reaction (RT-PCR); MMP-1 production in culture medium was detected by enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>Culture medium from UVB-irradiated keratinocytes increased MAP kinase activity and c-Jun mRNA expression in UVA-irradiated fibroblasts. IL-1alpha increased MAP kinase activity and c-Jun mRNA expression, IL-1alpha also increased c-Fos mRNA expression. Both culture media from UVB-irradiated human keratinocytes and externally applied IL-1alpha increased MMP-1 production in UVA-irradiated fibroblasts.</p><p><b>CONCLUSIONS</b>UVB-irradiated keratinocytes and IL-1alpha indirectly promote MMP-1 production in UVA-irradiated fibroblasts by increasing MAP kinase/AP-1 activity. IL-1 may play an important role in the paracrine activation and dermal collagen excessive degradation leading to skin photoaging.</p>