传统手工纸中9种金属元素的电感耦合等离子体原子发射光谱法测定及其溯源研究

将纸张样品剪至4mm×4mm以下的碎片,将竹子或竹浆(竹浆手工挤去水分)原料样品剪至4mm×4mm×4mm以下的碎屑,取样品0.500 0g于聚四氟乙烯消解罐内,依次加入4mL硝酸和2mL过氧化氢,对于纸张样品再加2mL水,放置15min后进行微波消解。消解完成后于135℃左右加热30min,赶去剩余硝酸,取下冷却(若样品消解不完全,再次加入4mL硝酸和0.5mL氢氟酸,重复上述消解步骤),过滤,用水定容至50.0mL,用电感耦合等离子体原子发射光谱法测定溶液中的钾、钙、钠、镁、铜、铝、铁、锌和钡。结果表明,9种金属元素的质量浓度在一定范围内与其发射强度呈线性关系,检出限在1.0~2.0mg·kg^-1之间。对样品进行加标回收试验,回收率在81.3%~114%之间,测定值的相对标准偏差(n=7)在1.2%~6.6%之间。采用此方法对手工纸制作工艺中7个关键环节中的物料中影响手工纸质量的金属元素进行了溯源研究,测定了6种典型手工纸中9种金属元素。

Determination of 9 Metal Elements in Traditional Handmade Paper by ICP-AES and Their Traceability Study

The paper sample was cut to pieces with size smaller than 4 mm×4 mm,and the bamboo or bamboo pulp raw material samples(bamboo pulp sample was squeezed out moisture)were cut to scraps with size smaller than 4 mm×4 mm×4 mm.The samples(0.500 0 g)was taken in a Teflon digestion tank,then 4 mL of nitric acid and 2 mL of hydrogen peroxide were added successively.For paper sample,2 mL of water was added.After standing for 15 minutes,microwave digestion was carried out.After digestion,the solution was heated at135℃for 30 min to remove the remaining nitric acid and then cooled.If the sample digestion was incomplete,4 mL of nitric acid and 0.5 mL of hydrofluoric acid were added,and the above digestion process was repeated.The digestion solution was filtered and the filter was diluted with water and made up to 50.0 mL.Inductively coupled plasma atomic emission spectrometry was used to determination of potassium,calcium,sodium,magnesium,copper,aluminum,iron,zinc and strontium in the solution.The results show that linear relationships were found between emission intensity and mass concentration of the 9 metal elements within definite ranges,and the detection limits were between 1.0 and 2.0 mg·kg^-1.Test for recovery was made by standard additon method to samples,giving values of recovery between 81.3%and 114%.The relative standard deviations of the measured values(n=7)were between 1.2% and 6.6%.The method was used to trace the metal elements affecting the quality of handmade paper in the materials of 7 main process for making handmade paper,and 9 metal elements in 6 typical samples were determined.