Polymeric monoliths fabricated in tips with embedded materials of choice are important in separation science. Polymeric backbone however interferes in the enrichment and thus affects efficiency. This work focuses on the in-tip fabrication of lanthanum oxide porous monolith and its application in the enrichment of phosphorylated peptides and lipids. Polycondensation reaction uses an aqueous solution of LaCl₃·7H₂O with N-methyl formamide as porogen and propylene oxide as initiator. The aging time of monolith and temperature condition for the reaction are optimized to attain porous monolithic tip. A comparison of (i) solid phase batch extraction using La₂O₃, (ii) La₂O₃ embedded in poly(glycidyl methacrylate (GMA)/divinylbenzene (DVB)) tip, and (iii) pure La₂O₃ monolithic tip shows improved enrichment efficiency in the case of pure La₂O₃ monolithic tip. The monolithic tip achieves selectivity of 1:4500 as compared to solid phase extraction (SPE)(1:3500) and limit of detection down to 0.25 fmol. The in-tip La₂O₃ monolith strategy has better batch to batch reproducibility, reduced time of enrichment, and ease of operation in comparison to solid phase batch extraction. The developed strategy enriches phospho- content from biological samples like phosvitin and lipovitellin from egg yolk and phospholipids/phosphopeptides from human serum. The enriched phospho- moieties are analyzed by matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) except the phospholipids where laser desorption ionization (LDI)-MS is employed.

中文翻译：

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尖端的氧化镧整体柱，用于磷酸化生物分子的富集

在尖端中用选择的嵌入材料制造的聚合物整料在分离科学中很重要。但是，聚合物主链会干扰富集，从而影响效率。这项工作的重点是氧化镧多孔整料的尖端制备及其在磷酸化肽和脂质富集中的应用。缩聚反应使用的是LaCl ₃ ·7H ₂ O水溶液，其中N-甲基甲酰胺为致孔剂，环氧丙烷为引发剂。优化整料的老化时间和反应的温度条件以获得多孔整料尖端。比较（i）使用La ₂ O ₃进行固相间歇萃取，（ii）La ₂ O ₃包埋在聚甲基丙烯酸缩水甘油酯（GMA）/二乙烯基苯（DVB）吸头中，以及（iii）纯La ₂ O ₃整体吸头在纯La ₂ O ₃整体吸头的情况下显示出提高的富集效率。与固相萃取（SPE）（1：3500）相比，整体式针头的选择性为1：4500，检出限低至0.25 fmol。尖端La ₂ O ₃与固相批次提取相比，整体策略具有更好的批次间重现性，缩短了富集时间并易于操作。制定的策略可丰富生物样品（如蛋黄的磷脂和卵磷脂）以及人血清中的磷脂/磷酸肽的磷含量。通过基质辅助的激光解吸电离质谱（MALDI-MS）分析富集的磷酸部分，但磷脂中采用的是激光解吸电离（LDI）-MS。