Detectors for Trace Organic Analysis by Liquid Chromatography: Principles and Applications

Kissinger, Peter T.; Felice, Lawrence J.; Miner, David J.; Preddy, Carl R.; Shoup, Ronald E.

doi:10.1007/978-1-4615-6731-8_3

Cited by 5 publications

(5 citation statements)

References 152 publications

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“…There is essentially no quantitative literature on the general effect of nonlinear detector response (Figure 1) on chromatographic peaks, although qualitative discussions of the phenomenon in the context of thermal conductivity detectors have appeared (1)(2)(3). In contrast, many papers (4)(5)(6), reviews (7)(8)(9)(10)(11), and monographs (12,13) on chromatographic detectors have described in detail the effect of nonideal transient de-tector and electronic response on peak height, area, variance, and shape. Since many chromatographic detectors have rather restricted ranges of linearity, we believe that the effect of nonlinear response is chromatographically significant.…”

mentioning

confidence: 99%

“…In this initial paper on detector nonlinearity effects on peak shape, I have therefore arbitrarily opted to assess the effect of the nonlinearity in the absence of the complicating effect of peak asymmetry. In the case of a perfectly GaussiEm peak, the various moments are as follows (31,32): i* = v^aC° (6) mi* = tR (7) m2* = 2 In all the work which follows, a moment designated with an asterisk will refer to a pure Gaussian peak. It should be noted that all odd central moments of any symmetric peEik, Gaussian or otherwise, are exactly zero.…”

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confidence: 99%

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Effect of detector nonlinearity on the height, area, width, and moments of chromatographic peaks based on a Gaussian model

Carr¹

1980

Anal. Chem.

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confidence: 99%

Effect of detector nonlinearity on the height, area, width, and moments of chromatographic peaks based on a Gaussian model

Carr¹

1980

Anal. Chem.

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“…at low pH, with pH 3.75 0.1 M acetate, pH 3.75 0.5 M phosphate, or pH 6.0 0.5 M acetate giving higher retention times (ca. [6][7] min, k' 4). The effect has been observed on several reversed-phase C18 and C8 columns but it is not known whether the retention shift is a result of mobile phase or stationary phase interactions.…”

Section: Methodsmentioning

confidence: 99%

“…The advantages of multidimensional chromatography are readily apparent when viewing a two-dimensional thin-layer chromatogram, and the theoretical and practical benefits of multidimensional high-performance liquid chromatography (HPLC) have been pointed out (1, 2). Two-dimensional HPLC separations have been performed by altering mobile phase or stationary phase selectivity and have permitted trace organic analysis in complex sample matrices (3)(4)(5)(6)(7)(8)(9)(10). Twodimensional reversed-phase HPLC systems should be especially applicable to determinations in aqueous physiological samples.…”

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confidence: 99%

Two-dimensional liquid chromatographic determination of (3-methoxy-4-hydroxyphenyl)glycol in urine

Anderson¹,

Schlicht²,

Cohen³

1983

Anal. Chem.

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The Important norepinephrine metabolite (3-methoxy-4hydroxyphenyl)glycol (MHPG) Is determined In human urine after a two-dimensional HPLC separation. Enzymatically hydrolyzed urine Is first separated on a C18 reversed-phase column using an acetate buffer mobile phase with fluorometrlc or UV absorbance monitoring. The eluent volume containing MHPG (*' 1.0) is collected. A portion of the collected sample Is reinjected on a reversed-phase column and separated with a phosphate buffer-methanol mobile phase. MHPG elutes In 5-6 min (k' 3) and Is detected by use of hydrodynamic amperometry. Recovery of added MHPG Is quantitative and samples are determined with a coefficient of variation of 6-7%.

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“…The effluent from the primary column is simply vented to a bypass so that the principal (secondary) chromatographic column is not contaminated. This technique has been described by Kissinger (16).…”

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Review: ultraselectivity through column switching and mode sequencing in liquid chromatography

Freeman¹

1981

Anal. Chem.

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Highly selective separations are achieved by changing the basis, or mode, of the separation during the separation process. In particular, mode control and mode sequencing Involve serial changes In the composition of the carrier and/or the stationary phase. To achieve this, simple valving circuits can be used with conventional LC apparatus. A review of Initial progress In this area shows that spectacular Improvements In LC performance are coming within reach experimentally.Modern liquid chromatography (LC) becomes more interesting and more powerful as one increases the number of columns. Usually an LC system contains a simple flowthrough sequence of one or perhaps a few columns. If this sequence is branched and switching devices are used, it then becomes possible to exert far more powerful control on the quality of and the basis for the separation. This leads to the idea of column switching, which is our present interest. The principle can be used in any multidimensional separation scheme, but LC offers an especially convenient area for the advantages to be realized.To illustrate, trace organic separations are often made exceedingly difficult by the large number of substances that tend to be present in the extracted sample, by the similarities among the given analytes (sought-for constituents), and by the need to remove major components that may be present in the extract. Sequential separation techniques are well suited to such problems. To see this, consider that practically unlimited separation capability is possible if the selectivity is systematically changed during the separation process (1). This involves variable combinations of column, carrier, and detector which cooperatively contribute to the overall system selectivity. The advantages of boosting the detector selectivity modes (hyphenated systems) was reviewed by Hirshfeld (2). Here I will review the advantages of a modern approach to sequential separation systems, also known as column switching, multidimensional chromatography, stationary-phase programming, mode switching, selectivity switching, and coupled columns, among other terms.The concept of mode, as a chromatographic property, might appear to be ambiguous, since it usually refers to the separation mechanism which the chromatographic system is intended to provide. It should be understood that the mode and the type of stationary phase are not necessarily the same. The mode, or separation mechanism, depends on the overall interactive relationship between the analyte, the carrier, and the substrate. Usually, the chromatographic mode is considered to be based on the nature of the column stationary phase. Thus, adsorption requires an adsorbent, ion exchange on ion exchanger, and so on. However, these modes are not realized unless specific conditions are met. Under certain

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Detectors for Trace Organic Analysis by Liquid Chromatography: Principles and Applications

Cited by 5 publications

References 152 publications

Effect of detector nonlinearity on the height, area, width, and moments of chromatographic peaks based on a Gaussian model

Effect of detector nonlinearity on the height, area, width, and moments of chromatographic peaks based on a Gaussian model

Two-dimensional liquid chromatographic determination of (3-methoxy-4-hydroxyphenyl)glycol in urine

Review: ultraselectivity through column switching and mode sequencing in liquid chromatography

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