工作场所空气质量.双联滤器取样设备和高效液相色谱法分析和测定空气中异氰酸盐

[中文适用范围]： 本国际标准给出了工作场所空气中异氰酸酯采样和分析的一般指南。 本国际标准适用于含有游离异氰酸酯官能团的有机化合物，特别适用于单体、聚合物和预聚物、蒸气和气溶胶的定量。 使用分离装置进行差分空气采样，该装置可以显示现场分析的异氰酸酯的物理状态。 然而，这种能力对于给定情况可能显示出局限性，例如，当在第一过滤器上收集的气溶胶含有游离单体时，该游离单体迁移到第二过滤器，然后被定量为气相异氰酸酯。 测定的芳香族单体包括甲苯二异氰酸酯（TDI）和4,4'-二异氰酸酯基二苯基甲烷（MDI）。 脂族单体包括异佛尔酮二异氰酸酯(IPDI)、4,4'-亚甲基双(环己基异氰酸酯)(HMDI)和1,6-六亚甲基二异氰酸酯(HDI)。 异氰酸酯低聚物和预聚物也可以使用该方法测定。 双过滤法旨在通过个人监测或固定位置监测来确定工作场所环境中有机异氰酸酯的短期（15 分钟）暴露浓度。 然而，如果预计仅以蒸气形式暴露，则采样时间可延长至 8 小时。 由于过滤器在采样后立即在现场衍生化，因此异氰酸酯气溶胶因与其他化学品反应而造成的损失可以忽略不计，除非反应非常快的异氰酸酯系统（例如聚氨酯应用中的 MDI 泡沫喷涂）。 该方法适用于测量空气中有机异氰酸酯，NCO 当量浓度范围为 0.01 μg/样品至 2.1 μg/样品，对应于 15 l 的浓度约为 0.67 μg/m3 至 140 μg/m3样品体积。 该范围大约是许多国家当局目前为单体设定的 5 ppb 阈值限值 (TLV) 的八倍。 [外文原描述]： ISO 17736:2010 gives general guidelines for the sampling and analysis of airborne isocyanates in workplace air. ISO 17736:2010 is appropriate for organic compounds containing free isocyanate functional groups and is specific for the quantification of monomers, polymers and prepolymers, vapours and aerosols. Differential air sampling is performed with a segregating device which can show the physical state of the isocyanates analysed as found in the field. This capacity, however, may show limitations for given situations, e.g. when aerosols collected on the first filter contain free monomer that migrates to the second filter and is then quantified as vapour phase isocyanate. The determination of aromatic monomers includes toluene diisocyanate (TDI) and 4,4'-diisocyanato-diphenylmethane (MDI). Aliphatic monomers include isophorone diisocyanate (IPDI), 4,4'-methylene bis-(cyclohexyl isocyanate) (HMDI) and 1,6-hexamethylene diisocyanate (HDI). Isocyanate oligomers and prepolymers can also be determined using this method. The double-filter method is designed to determine short-term (15 min) exposure concentrations of organic isocyanates in a workplace environment by personal monitoring or by fixed location monitoring. However, if the exposure is expected to be in vapour form only, then sampling time can be extended to 8 h. Since the filter is derivatized in the field immediately after sampling, loss of isocyanate aerosol because of its reaction with other chemicals is negligible except for very fast-reacting isocyanate systems such as foam spraying of MDI in polyurethane applications. The method is suitable for the measurement of airborne organic isocyanates in the NCO equivalent concentration range of 0,01 µg/sample to 2,1 µg/sample, corresponding to approximately 0,67 µg/m 3 to 140 µg/m 3 for a 15 l sample volume. This range brackets about eight times the current established threshold limit value (TLV) of 5 ppb for monomers set by many national authorities.