Lung Christie Y K, Darvell Brian W
Dental Material Science, Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong.
J Chromatogr A. 2004 Dec 17;1061(1):93-8. doi: 10.1016/j.chroma.2004.10.088.
Gas chromatography (GC) was investigated for the determination of residual methyl methacrylate (MMA) in heat-processed poly(methyl methacrylate) (PMMA) denture base material emphasizing recovery and validation. Standard solutions of MMA and emulsion-polymerized PMMA in dichloromethane were analysed, before and after distillation by a room-temperature air stream into a liquid nitrogen trap, and in the presence of PMMA by direct injection. Quantitative NMR analysis using dimethyl sulphoxide as internal calibration standard in deuterated chloroform solutions provided validation. Good concordance was observed between results under all conditions; no problems arose from direct injection of PMMA solution for GC. Good straight line responses in log-log plots were generally observed. For GC and MMA: log-log calibration curve (slope: 0.9552 +/- 0.0051, r2: 0.9992, n = 32) indicated some non-linearity (t = 8.875, p approximately 4 x 10(-10)). Distillation gave slope: 0.9751 +/- 0.0213 (NS versus unity; t = 1.172, p > 0.25). For PMMA solutions, distillation (r2: 0.9301) gave greater scatter than direct injection (r2: 0.9704). For NMR: log-log plot of calculated versus actual MMA (slope: 0.9363 +/- 0.0157, r2: 0.9969, n = 13) again indicated non-linearity (t = 4.0682, p = 0.0019). PMMA solutions gave slope: 0.9477 +/- 0.0328, r2 = 0.9858 (NS versus unity; t = 1.5941, p = 0.13). Determination of MMA in PMMA by GC is recommended.
研究了气相色谱法（GC）用于测定热加工聚甲基丙烯酸甲酯（PMMA）义齿基托材料中残留的甲基丙烯酸甲酯（MMA），重点在于回收率和验证。分析了MMA和乳液聚合PMMA在二氯甲烷中的标准溶液，在通过室温气流蒸馏到液氮阱之前和之后，以及在存在PMMA的情况下通过直接进样进行分析。使用二甲基亚砜作为氘代氯仿溶液中的内标进行定量NMR分析提供了验证。在所有条件下结果之间观察到良好的一致性；直接进样PMMA溶液进行GC分析没有出现问题。在对数-对数图中通常观察到良好的直线响应。对于GC和MMA：对数-对数校准曲线（斜率：0.9552±0.0051，r2：0.9992，n = 32）表明存在一定的非线性（t = 8.875，p约为4×10^(-10)）。蒸馏得到的斜率为：0.9751±0.0213（与1无显著差异；t = 1.172，p > 0.25）。对于PMMA溶液，蒸馏（r2：0.9301）比直接进样（r2：0.9704）产生的离散度更大。对于NMR：计算得到的MMA与实际MMA的对数-对数图（斜率：0.9363±0.0157，r2：0.9969，n = 13）再次表明存在非线性（t = 4.0682，p = 0.0019）。PMMA溶液的斜率为：0.9477±0.0328，r2 = 0.9858（与1无显著差异；t = 1.5941，p = 0.13）。建议采用GC法测定PMMA中的MMA。
