A new gradient elution chromatograph

Bombaugh, Karl J.; King, R. N.; Cohen, Allen J.

doi:10.1016/s0021-9673(00)99209-4

Cited by 15 publications

(8 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Notable modifications include the elimination of the need to operate at elevated temperatures; 8 incorporation of a second column and pumping system; 9 continuous alteration of the laser interrogation angle to adjust for RI changes in MP composition to allow for gradient separations; 10 and the use of thermooptic 11 and interferometric 12–14 methods to increase sensitivity. To date, however, refractometer design modifications have yet to result in significant adoption.…”

Section: Introductionmentioning

confidence: 99%

Refractive Index-Based Detection of Gradient Elution Liquid Chromatography using Chip-Integrated Microring Resonator Arrays

Wade

Bailey

2013

Anal. Chem.

View full text Add to dashboard Cite

Refractive index-based sensors offer attractive characteristics as non-destructive and universal detectors for liquid chromatographic separations, but a small dynamic range and sensitivity to minor thermal perturbations limit the utility of commercial RI detectors for many potential applications, especially those requiring the use of gradient elutions. As such, RI detectors find use almost exclusively in sample abundant, isocratic separations when interfaced with HPLC. Silicon photonic microring resonators are refractive index-sensitive optical devices that feature good sensitivity and tremendous dynamic range. The large dynamic range of microring resonators allows the sensors to function across a wide spectrum of refractive indices, such as that encountered when moving from an aqueous to organic mobile phase during a gradient elution – a key analytical advantage not supported in commercial RI detectors. Microrings are easily configured into sensor arrays, and chip-integrated control microrings enable real-time corrections of thermal drift. Thermal controls allow for analyses at any temperature and in the absence of rigorous temperature control, obviating extended detector equilibration wait times. Herein, proof of concept isocratic and gradient elution separations were performed using well characterized model analytes (e.g., caffeine, ibuprofen) in both neat buffer and more complex sample matrices. These experiments demonstrate the ability of microring arrays to perform isocratic and gradient elutions under ambient conditions, avoiding two major limitations of commercial RI-based detectors and maintaining comparable bulk RI sensitivity. Further benefit may be realized in the future through selective surface functionalization to impart degrees of post-column (bio)molecular specificity at the detection phase of a separation. The chip-based and microscale nature of microring resonators also makes it an attractive potential detection technology that could be integrated within lab-on-a-chip and microfluidic separation devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Refractive Index-Based Detection of Gradient Elution Liquid Chromatography using Chip-Integrated Microring Resonator Arrays

Wade

Bailey

2013

Anal. Chem.

View full text Add to dashboard Cite

show abstract

“…A number of liquid chromatographs are now available for the rapid separation of organic compounds (2)(3)(4)(5)(6)(7). However, most of these instruments will not tolerate the highly corrosive eluents often needed for inorganic separations, and they lack provision for rapid changing of eluents.…”

mentioning

confidence: 99%

“…Yet it provides rapid flow rates while using fine mesh column packing in either liquid partition or ion-exchange chromatography. Quantitative separations can be achieved in as little as [2][3] minutes per element. EXPERIMENTAL Instrumental Design.…”

mentioning

confidence: 99%

Application of forced-flow liquid chromatography to the determination of iron

Seymour¹,

Sickafoose²,

Fritz³

1971

Anal. Chem.

View full text Add to dashboard Cite

A liquid chromatograph is described which permits rapid separation of metal ions using strongly acidic eluents. The chromatograph is inexpensive to construct and provides for quick changing of eluents.With this equipment, iron(lll) can be separated from other ions and determined spectrophotometrically in less than 6 minutes. The iron is concentrated on a small anion exchange column and then is stripped from the column with dilute hydrochloric acid. The amount of iron is calculated from the peak height of the elution curve. Virtually all chemical and electrochemical methods for determining small amounts of a metal ion are at times subject to interferences that necessitate a chemical separation. Methods such as atomic spectrometry are very selective but their dependency on excitation conditions and matrix composition necessitates frequent calibration and standardization. A separation or concentration is often carried out in conjunction with flame methods.Ion exchange and partition chromatographic methods for separating metal ions from one another are quantitative and selective. However, most of the published methods are slow, often requiring 30 minutes or more to elute each element from the column. Recently a systematic scheme for 27 elements was published (/). By using samples of 25 to 50 mg and relatively small columns, the average elution time was reduced to around 15-20 minutes per element. Clearly a more rapid way to separate inorganic ions by ion exchange and partition chromatography would be useful.

show abstract

“…Solvent programming (gradient elution) is the primary method for altering k' values and increasing resolution in liquid chromatography. This approach has been discussed (134), and an apparatus described for the simultaneous and automatic programming of solvent flow and composition with time (58). A gradient mixer using a black and white paper curve for programming and magnetic valves for producing the gradient has been developed (699).…”

Section: Column Adsorption and Partition Chromatographymentioning

confidence: 99%