کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7608952 | 1493391 | 2018 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
On-tubing fluorescence measurements of the band broadening of contemporary injectors in ultra-high performance liquid chromatography
ترجمه فارسی عنوان
اندازه گیری های فلورسانس بر روی لوله گسترش انبساط انژکتور های معاصر در کروماتوگرافی مایع با کارایی فوق العاده بالا
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کلمات کلیدی
باند انژکتور گسترش می یابد، اندازه گیری فلورسانس، جریان تزریق سوزن، تزریق حلقه ثابت سهم حجم و هیدرودینامیکی،
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
چکیده انگلیسی
We report on a detailed study of the injection contribution to band broadening in contemporary UHPLC-instruments, using either flow-through needle or fixed loop injection (full loop). Using on-tubing fluorescence measurements at the outlet of the injector valve, very localized and undisturbed measurements were obtained. Varying both the flow rate and the injected volume allowed to split the injection variance (ÏV2,inj) in a volumetric component (related to the amount injected) and a hydrodynamic component (related to the flow rate). For the flow-through needle injector and for the small injection volumes (<2â¯Î¼L) typically used in UHPLC, it was found that the volumetric contribution (i.e. the part of ÏV2,inj, that increases with increasing injection volume) is given by a value of ÏV2,inj,volâ¯=â¯0.8 to 1·Vinj2 rather than by the value of 0.125 to 0.2·Vinj2 that is normally assumed in literature. For the hydrodynamic contribution to ÏV2,inj, (i..e, the part which remains present even for very small injection volumes), a clear increase in dispersion with flow rate is found, reaching a plateau around 0.8ml/min of 0.6â¯Î¼L² or 1.2â¯Î¼L² for the 75â¯Î¼m and 120â¯Î¼m needle seat capillaries respectively. The difference between both shows the clear advantage of using a low dispersion 75â¯Î¼m injection needle seat capillary. For a loop-type injector operated in a full-loop mode, the increase in peak variance with the injection volume is much less pronounced, leading to a total injector variance given by ÏV2,injâ¯=â¯0.34â¯Î¼L²â¯+â¯0.12·Vinj2 over the entire range of investigated injection volumes of 1.1â¯Î¼L up to 4.5â¯Î¼L when using 120â¯Î¼m or narrower ID loops. This expression was nearly completely independent of the flow rate. For larger ID sample loops, a clear increase of peak variance with flow rate at fixed injection volume was observed (ÏV2,inj increases with 20% for a 170â¯Î¼m ID loop and with 70% for a 220â¯Î¼m ID loop from 0.3 to 1â¯ml/min).
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Chromatography A - Volume 1535, 2 February 2018, Pages 44-54
Journal: Journal of Chromatography A - Volume 1535, 2 February 2018, Pages 44-54
نویسندگان
Ken Broeckhoven, Kim Vanderlinden, Davy Guillarme, Gert Desmet,