Molander P, Haugland K, Fladseth G, Lundanes E, Thorud S, Thomassen Y, Greibrokk T
Department of Chemistry, University of Oslo, Norway.
J Chromatogr A. 2000 Sep 15;892(1-2):67-74. doi: 10.1016/s0021-9673(99)01351-5.
A temperature-programmed packed capillary LC method with large-volume injection on-column focusing has been developed for screening and determination of 1-(2-methoxyphenyl)piperazine derivatives of airborne toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, hexamethylenediisocyanate and methylenebisphenyl-4,4-diisocyanate, based on sampling methods described in MDHS 25/3. Injection volumes up to 100 microl were successfully loaded onto the 250x0.32 mm I.D. capillary column packed with 3 microm Hypersil ODS particles. The isocyanate derivatives were loaded at 10 degrees C and eluted by a three-step temperature program starting at 10 degrees C for 10 min, followed by a temperature ramp of 2.5 degrees C min(-1) to 45 degrees C and then 9.9 degrees C min(-1) to 90 degrees C. The mobile phase consisted of acetonitrile-acetate buffer (3% triethylamine, pH 4.5) (45:55, v/v). The isocyanate derivatives were dissolved in acetonitrile-acetate buffer (3% triethylamine, pH 4.5) (30:70, v/v) to achieve sufficient focusing. The concentration limit of detection of the individual derivatives utilizing an "U" shaped flow cell with a 8.0 mm light path and an injection volume of 100 microl was 44, 87, 43 and 210 pg ml(-1) for toluene-2,6-diisocyanate, hexamethylenediisocyanate, toluene-2,4-diisocyanate and methylenebisphenyl-4,4-diisocyanate, respectively. Within the investigated concentration range, 10-500 ng ml(-1), the linear calibration curves gave correlation coefficients ranging from 0.994 to 0.998. The repeatability of the method with regard to retention time and peak height ranged from 0.3 to 1.1% and 1.1 to 2.3% (n=9) relative standard deviation, respectively. The average recovery of the method, with regard to toluene-2,4-diisocyanate, was 97.7+/-1.6% (n=9).
基于MDHS 25/3中描述的采样方法，开发了一种程序升温填充毛细管液相色谱法，该方法采用大体积进样柱上聚焦技术，用于筛选和测定空气中甲苯-2,4-二异氰酸酯、甲苯-2,6-二异氰酸酯、六亚甲基二异氰酸酯和亚甲基双苯基-4,4-二异氰酸酯的1-(2-甲氧基苯基)哌嗪衍生物。成功将高达100微升的进样体积加载到内径为250x0.32毫米、填充有3微米Hypersil ODS颗粒的毛细管柱上。异氰酸酯衍生物在10℃下加载，通过三步程序升温洗脱，起始温度为10℃，保持10分钟，然后以2.5℃/分钟的速率升温至45℃，再以9.9℃/分钟的速率升温至90℃。流动相由乙腈-醋酸盐缓冲液（3%三乙胺，pH 4.5）（45:55，v/v）组成。异氰酸酯衍生物溶解在乙腈-醋酸盐缓冲液（3%三乙胺，pH 4.5）（30:70，v/v）中以实现充分聚焦。对于甲苯-2,6-二异氰酸酯、六亚甲基二异氰酸酯、甲苯-2,4-二异氰酸酯和亚甲基双苯基-4,4-二异氰酸酯，使用光程为8.0毫米的“U”形流通池和100微升进样体积时，各衍生物的检测浓度下限分别为44、87、43和210皮克/毫升。在所研究的浓度范围10 - 500纳克/毫升内，线性校准曲线的相关系数在0.994至0.998之间。该方法在保留时间和峰高方面的重复性相对标准偏差分别为0.3%至1.1%和1.1%至2.3%（n = 9）。该方法对于甲苯-2,4-二异氰酸酯的平均回收率为97.7±1.6%（n = 9）。
