应用离子色谱法(IC)测定芳香族聚酰胺纤维中硫、钠、钾、镁及钙.测定阴离子时,试样置于铂坩埚中用艾斯卡试剂覆盖,置于马弗炉中,450 ℃灼烧1 h使有机物碳化,取出,稍冷,再加少许艾斯卡试剂,升温至850 ℃灼烧1.5 h,使有机物完全分解.坩埚中的熔块经冷却后用去离子水浸出,用18 mmol·L-1碳酸钠及17 mmol·L-1碳酸氢钠混合溶液定容后,用IC法的阴离子方式测定.用IC法测定阳离子时,试样置于铂坩埚中,不必加艾斯卡试剂,置于马弗炉直接灼烧至有机物完全分解.残渣用1 mol·L-1硝酸或1 mol·L-1盐酸超声波处理,用去离子水洗涤坩埚并定容至100 mL,按所测得峰面积值从标准曲线查得其含量.用此方法测定SO2-4,Na+,K+,Mg2+及Ca2+的检出限依次为0.02,0.25,0.25,0.70及0.80 mg·L-1.

Ion chromatography (IC) was applied to the determination of some inorganic elements in aromatic polyamide fiber (Twaron).For the determination of anions,the sample in a platinum crucible was covered with Eschka mixture containing 3 parts of anhydrous Na2CO3 and 2 parts of zinc oxide,and heated in a muffle furnace at 450 ℃ for 1 h,some more of the Eschka mixture was added and heated at 850 ℃ for 1.5 h,to decompose the organic substance completely.The cooled melt in the crucible was dissolved in deionized water,and diluted to 100 mL in a volumetric flask with a mixed solution containing 18 mmol·L-1 Na2CO3 and 17 mmol·L-1 NaHCO3.This sample solution was used for IC determination of anions.For the IC-determination of cations (e.g.alkali metal and alkaline earth metal ions),the sample in the crucible was burned directly in a muffle furnace,without adding the Eschka mixture,until complete oxidation of the organic substances was attained.The residue in the crucible was treated ultrasonically with 1 mol·L-1 HNO3 or 1 mol·L-1 HCl,and transferred to a 100 mL volumetric flask,wash the crucible and diluted to 100 mL with deionized water.Working conditions of the IC determination were described,and the results of the 5 elements were found by the standard curve method.Detection limits for SO2-4,Na+,K+,Mg2+ and Ca2+ were found as 0.02,0.25,0.25,0.70 and 0.80 mg·L-1 respectively.