Bagon D A, Warwick C J, Brown R H
Am Ind Hyg Assoc J. 1984 Jan;45(1):39-43. doi: 10.1080/15298668491399334.
The United Kingdom Health and Safety Commission has set a 'common control limit' for workplace exposure to all isocyanates. This limit replaces the previous United Kingdom threshold limit values, which were set for just four species of monomeric isocyanate compounds. This new control limit is set at 20 micrograms of isocyanate group per cubic meter of air expressed as an eight-hour weighted average, and 70 micrograms of isocyanate group per cubic meter of air as a 10-minute weighted average. These new control limits make it necessary that analytical methods should be capable of measuring total isocyanate concentration, including monomers and prepolymers. A previously available method for determining isocyanate monomers using 1-(2-methoxyphenyl)piperazine with high performance liquid chromatography (HPLC) has been modified to measure both monomer and prepolymer. A dual detection system employing electrochemical and ultra-violet detectors is used to identify isocyanate-derived HPLC peaks which are then quantified by reference to a monomer standard, thus avoiding the necessity of isolating prepolymer standards. The total isocyanate-in-air concentration is then calculated from the total area of the isocyanate-derived HPLC peaks. The precision of the method is better than 10% over the range 35 to 140 micrograms(NCO)/m3 for a 10 min sample.
英国健康与安全委员会已为工作场所接触所有异氰酸酯设定了“通用控制限值”。该限值取代了之前仅针对四种单体异氰酸酯化合物设定的英国阈限值。这个新的控制限值设定为每立方米空气中异氰酸酯基团20微克，以八小时加权平均值表示；每立方米空气中异氰酸酯基团70微克，以十分钟加权平均值表示。这些新的控制限值使得分析方法必须能够测量包括单体和预聚物在内的总异氰酸酯浓度。一种先前可用的使用1 - (2 - 甲氧基苯基)哌嗪与高效液相色谱法(HPLC)测定异氰酸酯单体的方法已被改进，以同时测量单体和预聚物。采用电化学和紫外检测器的双检测系统用于识别异氰酸酯衍生的HPLC峰，然后通过参照单体标准进行定量，从而避免了分离预聚物标准品的必要性。然后根据异氰酸酯衍生的HPLC峰的总面积计算空气中总异氰酸酯浓度。对于10分钟的样品，该方法在35至140微克(NCO)/立方米的范围内精度优于10%。
