计算程序-多波长直线回归法测定散列通片中三组分的含量

本文研究并建立了计算程序-三组分多波长直线回归法,用于快速测定散列通片中对乙酰氨基酚、异丙安替比林和咖啡因的含量.散列通片中三组分的紫外吸收光谱严重重叠,采用数学分离-化学计量学方法排除各组分的互相干扰,在230～290 nm波长区间选择31个波长点的光谱数据,利用三组分多波长直线回归计算程序进行计算,直接测定散列通片...     

Two-column Sequential Injection Chromatography—New approach for fast and effective analysis and its comparison with gradient elution chromatography

This work presents novel approach in low-pressure chromatography flow systems—two-column Sequential Injection Chromatography (2-C SIC) and its comparison with gradient elution chromatography on the same instrument. The system was equipped with two different chromatographic columns (connected to selection valve in parallel design) for isocratic separation and determination of all components in composed anti-inflammatory pharmaceutical preparation (tablets). The sample was first injected on the first column of length 30 mm where less retained analytes were separated and then the sample was injected on the second column of length 10 mm where more retained analytes were separated. The SIC system was based on a commercial SIChrom™ manifold (8-port high-pressure selection valve and medium-pressure syringe pump with 4 mL reservoir) (FIAlab^®, USA) with two commercially available monolithic columns the “first column” Chromolith^® Flash RP-18e (25 mm × 4.6 mm i.d. with guard column 5 mm × 4.6 mm i.d.) and the “second column” Chromolith^® RP-18e (10 mm × 4.6 mm i.d.) and CCD UV-vis detector USB 4000 with micro-volume 1.0 cm Z flow cell. Two mobile phases were used for analysis (one for each column). The mobile phase 1 used for elution of paracetamol, caffeine and salicylic acid (internal standard) was acetonitrile/water (10:90, v/v, the water part of pH 3.5 adjusted with acetic acid), flow rate was 0.9 mL min⁻¹ (volume 3.0 mL of mobile phase per analysis). The mobile phase 2 used for elution of propyphenazone was acetonitrile/water (30:70, v/v); flow rate was 1.2 mL min⁻¹ (volume 1.5 mL of mobile phase per analysis). Absorbance was monitored at 210 nm. Samples were prepared by dissolving of one tablet in 30% acetonitrile and 10 μL of filtered supernatant was injected on each column (2 × 10 μL). The chromatographic resolution between all compounds was >1.45 and analysis time was 5.5 min under the optimal conditions. Limits of detection were determined at 0.4 μg mL⁻¹ for paracetamol, at 0.5 μg mL⁻¹ for caffeine and at 0.7 μg mL⁻¹ for propyphenazone. The new two-column chromatographic set-up developed as an alternative approach to gradient elution chromatography shows evident advantages (time and solvent reduction more than one-third) as compared with single-column gradient SIC method with Chromolith^® Flash RP-18 (25 mm × 4.6 mm i.d. with guard column 5 mm × 4.6 mm i.d.).