双波长光谱法测定纺织品中的微量甲醛

Determination of low content formaldehyde in textiles by dual wavelength spectrum

在测定纺织品中甲醛时,提出了一种以500 nm吸光度为基准并结合412 nm吸光度的双波长检测方法。结果表明,采用单波长的计算方法(不考虑基线漂移产生的误差)时,尽管显色组和空白组的平行试验结果之间的相对误差并不显著(3.6%),但其差值的最大不确定性可达6.4%;而采用双波长法,扣除基线漂移(500 nm处的吸光度)的影响,其显色组和空白组吸光度差值的最大不确定性仅为0.30%,显著提高了甲醛检测的灵敏度(定量极限=7.89 mg/kg),适用于纺织品中低含量甲醛的准确检测。

The spectral errors caused by the light scattering and baseline drafting due to the instability of spectrophotometer are discussed, and a dual-wavelength spectroscopic method for accurate determination of formaldehyde in textiles by taking the absorbances at 500 nm （as a reference） and 412 nm is pro- posed. The results show that the relative errors on measuring the absorbances of colored and blank sample solution by single-wavelength method are within 3.6%, which led to a maximum uncertainty of 6.4 for the net absorbance for formaldehyde; while such errors from dual-wavelength method are only 0.30%. The dual-wavelength method is also sensitive with the limit of quantitation （LOQ）=7.89 mg/kg. Therefore, the present method is more suitable for the analysis of lower amount of formaldehyde in textile products.