Determination of 1-(2-methoxyphenyl)piperazine derivatives of isocyanates at low concentrations by temperature-programmed miniaturized liquid chromatography

• Published in: Journal of Chromatography A 2000-09, Vol.892 (1), p.67-74
• Main Authors: Molander, P, Haugland, K, Fladseth, G, Lundanes, E, Thorud, S, Thomassen, Y, Greibrokk, T
• Format: Article
• Language: English
• Subjects: Analysis methods; Analytical chemistry; Applied sciences; Atmospheric pollution; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, Liquid - methods; Exact sciences and technology; Isocyanates; Isocyanates - chemistry; Methoxyphenylpiperazine; Other chromatographic methods; Piperazines - analysis; Pollution; Reproducibility of Results; Sensitivity and Specificity; Temperature
• ISSN: 0021-9673
• 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 μl were successfully loaded onto the 250×0.32 mm I.D. capillary column packed with 3 μm Hypersil ODS particles. The isocyanate derivatives were loaded at 10°C and eluted by a three-step temperature program starting at 10°C for 10 min, followed by a temperature ramp of 2.5°C min −1 to 45°C and then 9.9°C min −1 to 90°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 μl 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).