White John, Johnson Paul, Pengelly Ian, Keen Chris, Coldwell Matthew
Health and Safety Laboratory, Harpur Hill, Buxton, UK.
Ann Occup Hyg. 2012 May;56(4):466-80. doi: 10.1093/annhyg/mer114. Epub 2011 Dec 26.
The method that is probably the most commonly used worldwide for the determination of total organic isocyanates (NCO) in air is the Health and Safety Executive method, MDHS 25/3, Organic Isocyanates in Air, and its variants. This paper summarizes some of the research and development work carried out by Health and Safety Laboratory on this method since its publication in 1999 with the eventual aim of incorporating this work in an updated version of MDHS 25 (i.e. MDHS 25/4). The work falls into two main areas: use of liquid chromatography/mass spectrometry (LC/MS) as an alternative to liquid chromatography with electrochemical and ultraviolet/visible detection (LC/EC/UV) and evaluation of 'solid-phase' sampling techniques as an alternative to the impinger-filter combination stated in MDHS 25/3. This paper deals primarily with HDI-based NCO but some comments regarding aromatic NCO (MDI and TDI) are included for completeness. An LC/MS/MS version of MDHS 25/3 has been developed that gives improved performance to the 'classical' version of MDHS 25/3 using EC/UV detection. The LC/MS/MS offers significant advantages over the EC/UV version of MDHS 25/3 in that it is more sensitive, provides improved identification, and has been found to be easier to use. The solid-phase samplers evaluated were a double-thickness glass-fibre (GF/B) filter coated with 1-(2-methoxyphenyl)piperazine (MP) reagent in an IOM (Institute of Occupational Medicine) sampling head ('FIN-MP' sampler) and an MP-impregnated polyurethane foam sponge (PUF) with an MP-coated glass-fibre (GF/A) backup filter also in an IOM sampling head ('Rudzinski' sampler). Both samplers were found to give acceptable performance for the sampling of oligomeric HDI in workplace air and in laboratory simulations when compared to the impinger-filter combination at levels corresponding to the UK short-term limit (70 μg m(-3)). For practical reasons, the FIN-MP sampler was the preferred alternative.
全球范围内测定空气中总有机异氰酸酯（NCO）最常用的方法可能是健康与安全执行局的方法MDHS 25/3《空气中的有机异氰酸酯》及其变体。本文总结了健康与安全实验室自1999年该方法发布以来开展的一些研发工作，最终目标是将这些工作纳入MDHS 25的更新版本（即MDHS 25/4）。这项工作主要分为两个领域：使用液相色谱/质谱联用（LC/MS）替代具有电化学和紫外/可见检测功能的液相色谱（LC/EC/UV），以及评估“固相”采样技术替代MDHS 25/3中所述的冲击器-过滤器组合。本文主要讨论基于六亚甲基二异氰酸酯（HDI）的NCO，但为了完整性也包含了一些关于芳香族NCO（二苯基甲烷二异氰酸酯（MDI）和甲苯二异氰酸酯（TDI））的评论。已开发出MDHS 25/3的LC/MS/MS版本，与使用电化学/紫外检测的“经典”MDHS 25/3版本相比，性能有所提升。LC/MS/MS相对于MDHS 25/3的电化学/紫外版本具有显著优势，它更灵敏、提供更好的鉴定效果，并且发现更易于使用。评估的固相采样器包括在职业医学研究所（IOM）采样头中涂有1-（2-甲氧基苯基）哌嗪（MP）试剂的双层玻璃纤维（GF/B）过滤器（“FIN-MP”采样器），以及在IOM采样头中带有MP涂层玻璃纤维（GF/A）备用过滤器的MP浸渍聚氨酯泡沫海绵（PUF）（“鲁津斯基”采样器）。与冲击器-过滤器组合相比，在对应于英国短期接触限值（70 μg/m³）的水平下，无论是在工作场所空气中还是在实验室模拟中，这两种采样器对低聚物HDI的采样性能都被认为是可接受的。出于实际原因，FIN-MP采样器是更优选的替代方案。
