蒸馏-高分辨连续光源原子吸收光谱法测定果脯中二氧化硫

硫在富燃空气-乙炔火焰中可以形成CS双原子分子。CS双原子分子的吸收轮廓与原子光谱吸收类似,因此可以利用原子吸收光谱方法进行定量分析。建立了高分辨连续光源原子吸收光谱法分析果脯中二氧化硫含量的方法。果脯中的二氧化硫经酸化、蒸馏、过氧化氢氧化等过程转变为硫酸根,通过连续光源原子吸收光谱法检测。对影响二氧化硫检测灵敏度的乙炔流量、火焰高度等仪器参数进行了优化,并考察了样品中硫酸根、硫代硫酸根等不同形态硫对二氧化硫分析的干扰。优化条件下,在257.961nm波长的检出限为52.4mg·kg~(-1);相对标准偏差小于10%。应用于北京市售果脯样品二氧化硫含量测定,平均回收率在85.7%~115.7%之间。该方法具有准确快速、干扰少等优点,拓宽了原子吸收光谱法的应用范围。

Detection of Sulfur Dioxide in Preserved Fruits with High Resolution Continuum Source Atomic Absorption Spectrometry Assisted with Distillation

The CS diatomic molecules can be transformed from sulfur in fuel‐rich air acetylene flame .The absorbance of CS can be detected with atomic absorption spectrometry as the CS line profile is similar to the atomic absorption .A novel method was established to detect the sulfur dioxide in preserved fruits with high resolution continuum source atomic absorption spectrometry . The sulfate ions can be transformed from the SO2 in preserved fruits after the experience of acidity ,distillation and oxidation with H2 O2 .The instrumental parameters influencing on the sensitivity of SO 2 determination were optimized ,including the veloci‐ty of acetylene ,the flame height ,etc .And the interference of different S species ,such as SO2 -4 ,S2 O2 -3 ,etc on the SO2 recovery was observed .In the optimal conditions ,the limit of detection under the wavelength of 257.961 nm was 52.4 mg · kg -1 ,and the relative standard deviation was below 10% .The average spiked recoveries between 85.7% and 115.7% were achieved when this method was used for real preserved fruits samples analysis .It’s proved that this method has the merits of high accuracy rap‐id analysis and low interference ,and the application areas of atomic absorption spectrometry were extended .