On-line Sample Preparation System Using Column-Switching HPLC for the Structure Elucidation of Compounds in Mixtures by NMR

Yokoyama, Yumi; Kishi, Naoya; Tanaka, Masayuki; Asakawa, Naoki

doi:10.2116/analsci.16.1183

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…Cutting a smaller peak volume (<<2.5 ml) and/or operating the semi-preparative LC at a reduced flow-rate may work under limited situations, but this would clearly curtail the full potential of using semipreparative LC. A more sophisticated loop dilution scheme has been reported for semi-preparative chromatography, 14 but this involves the use of a reduced LC flow-rate, a relatively large volume trapping column (4.6 ð 10 mm), an additional D 2 O solvent exchange step and finally rechromatography on a narrow-bore secondary column to concentrate the analyte prior to NMR analysis. To integrate semi-preparative LC-SPE-NMR ( LC-SPE-NMR) we have taken a different approach to implement the mixing and dilution steps.…”

Section: Resultsmentioning

confidence: 99%

The design of an on‐line semi‐preparative LC–SPE–NMR system for trace analysis

Alexander

2005

Magnetic Reson in Chemistry

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This paper reports the design of an on-line semi-preparative LC-SPE-NMR system and its use in the structural analysis of mixture components at the 0.02-1% level. The combination provides at least a five fold mass sensitivity increase over that obtained from typical analytical LC-SPE systems and a >30-fold total NMR sensitivity enhancement over analysis by LC-NMR. This is accomplished by using a novel on-line device to store, dilute (1-100-fold) and deliver (at an optimized flow-rate) the isolated component of interest to an SPE trap unit. The SPE unit consists of two cartridges connected in parallel to increase the overall SPE capacity and also to decrease the flow-rate through each trap for enhanced trapping efficiency. As the coupling of semi-preparative LC with NMR (through SPE) is well matched in terms of optimal mass loading for both techniques, only one LC-SPE cycle is required to enrich a 50 microg ml(-1) component (1% in a 5 mg ml(-1) mixture) for the acquisition of heteronuclear (1)H-(13)C NMR data using a conventional NMR flow probe. Furthermore, analytes at the 0.02% level (approximately 1 microg ml(-1)) can be studied using 2D (1)H NMR techniques if peak cuts from replicate sample injections (> or =3) are accumulated into the storage/dilution unit and the resulting solution processed by just one SPE trap and elute cycle.

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Section: Resultsmentioning

confidence: 99%

The design of an on‐line semi‐preparative LC–SPE–NMR system for trace analysis

Alexander

2005

Magnetic Reson in Chemistry

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“…To address this serious issue, we investigated pretreatment conditions and then employed additional flow line and solvent delivery pump called “autodilution” device. Improved recovery by dilution of sample in column switching HPLC with conventional scale infection has been reported , but pump‐injection system had more complicated problems to be fixed. In this study, we optimized related parameters for this device and then the validation to confirm reliability of the analytical method was examined.…”

Section: Introductionmentioning

confidence: 99%

Trace level determination of polycyclic aromatic hydrocarbons in river water with automated pretreatment HPLC

Watabe

Kubo

Tanigawa

et al. 2013

J of Separation Science

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A novel on-line pretreatment pump-injection HPLC system for polycyclic aromatic hydrocarbons is proposed. We report novel pump-injection HPLC-based on-line SPE with a specially designed pretreatment column for the determination of trace amounts of chemical substances in surface water. Polycyclic aromatic hydrocarbons are well known for strong carcinogenicity and thus a severe concentration control is required for drinking water and/or river water, which is the main resource of tap water. We found it possible to detect ng/L levels of polycyclic aromatic hydrocarbons by using pump-injection column switching HPLC with fluorescence detection. To avoid the phenomenon, in which polycyclic aromatic hydrocarbons can be often adsorbed on the surface of flow lines of HPLC by their highly hydrophobicity especially resin-made parts in sample delivery pump, we employed "autodilution" device that provides reliable recovery and repeatability. Additionally, real water samples were collected and then the spiked polycyclic aromatic hydrocarbons were determined at ng/L levels.

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“…13,14 In the area of NMR, an online sample preparation system using column switching HPLC has been reported. 15 Typically, when designing such separations, columns with complementary selectivity are normally employed in order to maximize the separation space. 10,11 However, in the preparative area, two similar phases can be employed, as the objective of the first dimension is to allow principally the component of interest to be delivered to the second column, where the separation may be tuned to resolve a few components from a much simpler sample matrix.…”

Section: Introductionmentioning

confidence: 99%

The design of a multi‐dimensional LC‐SPE‐NMR system (LC²‐SPE‐NMR) for complex mixture analysis

Alexander

Bernard

2005

Magnetic Reson in Chemistry

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In this communication, we describe the design of an online multi-chromatographic approach to the routine NMR analyses of low-level components ( approximately 0.1%) in complex mixtures. The technique, termed LC(2)-SPE-NMR, optimally combines multi-dimensional liquid chromatography with SPE technology for isolating, enriching and delivering trace analytes to the NMR probe. The fully automated LC(2)-SPE-NMR system allows for maximal loading capacity (in the first, preparative LC dimension), close to optimal peak resolution (in the second, analytical LC dimension) and enhanced sample concentration (through SPE). Using this system, it is feasible to conveniently conduct a wide range of NMR experiments on, for example, drug impurities at the low microgram per milliliter level, even for components poorly resolved in the first dimension. Such a sensitivity gain significantly elevates the analytical power of online NMR technology in terms of the level at which substances of pharmaceutical significance can be structurally characterized.

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On-line Sample Preparation System Using Column-Switching HPLC for the Structure Elucidation of Compounds in Mixtures by NMR

Cited by 5 publications

References 12 publications

The design of an on‐line semi‐preparative LC–SPE–NMR system for trace analysis

The design of an on‐line semi‐preparative LC–SPE–NMR system for trace analysis

Trace level determination of polycyclic aromatic hydrocarbons in river water with automated pretreatment HPLC

The design of a multi‐dimensional LC‐SPE‐NMR system (LC²‐SPE‐NMR) for complex mixture analysis

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On-line Sample Preparation System Using Column-Switching HPLC for the Structure Elucidation of Compounds in Mixtures by NMR

Cited by 5 publications

References 12 publications

The design of an on‐line semi‐preparative LC–SPE–NMR system for trace analysis

The design of an on‐line semi‐preparative LC–SPE–NMR system for trace analysis

Trace level determination of polycyclic aromatic hydrocarbons in river water with automated pretreatment HPLC

The design of a multi‐dimensional LC‐SPE‐NMR system (LC2‐SPE‐NMR) for complex mixture analysis

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The design of a multi‐dimensional LC‐SPE‐NMR system (LC²‐SPE‐NMR) for complex mixture analysis