Carr John E, Kwok Kaho, Webster Gregory K, Carnahan Jon W
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.
J Pharm Biomed Anal. 2006 Jan 23;40(1):42-50. doi: 10.1016/j.jpba.2005.06.033. Epub 2005 Aug 10.
Atomic spectrometry, specifically inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) show promise for heteroatom-based detection of pharmaceutical compounds. The combination of ultrasonic nebulization (USN) with membrane desolvation (MD) greatly enhances detection limits with these approaches. Because pharmaceutical analyses often incorporate liquid chromatography, the study herein was performed to examine the effects of solvent composition on the analytical behaviors of these approaches. The target analyte was phosphorus, introduced as phosphomycin. AES response was examined at the 253.7 nm atom line and mass 31 ions were monitored for the MS experiments. With pure aqueous solutions, detection limits of 5 ppb (0.5 ng in 0.1 mL injection volumes) were obtained with ICP-MS. The ICP-AES detection limit was 150 ppb. Solvent compositions were varied from 0 to 80% organic (acetonitrile and methanol) with nine buffers at concentrations typically used in liquid chromatography. In general, solvents and buffers had statistically significant, albeit small, effects on ICP-AES sensitivities. A few exceptions occurred in cases where typical liquid chromatography buffer concentrations produced higher mass loadings on the plasma. Indications are that isocratic separations can be reliably performed. Within reasonable accuracy tolerances, it appears that gradient chromatography can be performed without the need for signal response normalization. Organic solvent and buffer effects were more significant with ICP-MS. Sensitivities varied significantly with different buffers and organic solvent content. In these cases, gradient chromatography will require careful analytical calibration as solvent and buffer content is varied. However, for most buffer and solvent combinations, signal and detection limits are only moderately affected. Isocratic separations and detection are feasible.
原子光谱法，特别是电感耦合等离子体原子发射光谱法（ICP - AES）和质谱法（ICP - MS）在基于杂原子的药物化合物检测方面显示出前景。超声雾化（USN）与膜去溶剂化（MD）的结合极大地提高了这些方法的检测限。由于药物分析通常采用液相色谱法，因此本文进行了研究以考察溶剂组成对这些方法分析行为的影响。目标分析物是磷，以磷霉素形式引入。在253.7 nm原子线处检测AES响应，并在质谱实验中监测质量数为31的离子。对于纯水溶液，ICP - MS的检测限为5 ppb（进样体积0.1 mL时为0.5 ng）。ICP - AES的检测限为150 ppb。溶剂组成从0%至80%的有机溶剂（乙腈和甲醇）变化，同时使用九种液相色谱中常用浓度的缓冲液。总体而言，溶剂和缓冲液对ICP - AES灵敏度具有统计学上显著但较小的影响。在典型的液相色谱缓冲液浓度导致等离子体上质量负载较高的情况下出现了一些例外情况。有迹象表明等度分离可以可靠地进行。在合理的准确度公差范围内，似乎可以进行梯度色谱分析而无需信号响应归一化。有机溶剂和缓冲液对ICP - MS的影响更为显著。灵敏度随不同缓冲液和有机溶剂含量而显著变化。在这些情况下，随着溶剂和缓冲液含量的变化，梯度色谱分析需要仔细的分析校准。然而，对于大多数缓冲液和溶剂组合，信号和检测限仅受到适度影响。等度分离和检测是可行的。
