Selective determination of phenols in water by a two-trap tandem extraction system followed by liquid chromatography

Corcia, Antonio Di; Marchese, Stefano; Samperi, Roberto

doi:10.1016/0021-9673(93)80085-m

“…The most common ones are grap h i t i zed carbon bl a ck s (GCB) with a low specific surface area around 100 m 2 /g, so that they are often described as non-porous sorbents. Their higher efficiency over C 18 silica for trapping polar pesticides have been extensively shown by the group of Di Corcia et al [1,[25][26][27][28]. GCB are not enough pressure resistant to be used in LC so that no data indicating the LC behaviour of solutes are available.…”

Section: Carbonaceous Sorbentsmentioning

confidence: 99%

Multiresidue solid-phase extraction for trace-analysis of pesticides and their metabolites in environmental water

Pichon¹

1998

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Recent research on the fate and transformation of pesticides in the environment has pointed out the need for including more and more polar analytes in multiresidue analysis. Liquid chromatography have been shown to be suitable for mu l t i residue sep a ration of many compounds over a wide ra n ge of polarity without prev i o u s derivatization. Examples can be found in the literature, the most impressive one being the multiresidue separation of 72 pesticides in one run published by Di Corcia and Marchetti some time ago [1]. However, despite the advances in separation and quantifi c ation tech n i q u e s , no sample can be directly analyzed and a multiresidue extraction is a compulsory step in the analytical procedure.In recent years, enrichment of trace compounds on suitable sorbents has been shown to be an interesting alternative to LLE, and has now become a reliable and useful tool for sample handling. In addition, many modern pesticides and identified degra d ation products are fa i rly soluble in water and are therefore less amenable to solvent extraction. Automation and new trends in SPEThe solid-phase extraction (SPE) area has been very active these past years, certainly due to the now well-recognized trends for using solvent-free methods in environmental analytical laboratories and for its suitability to automation [2]. The four individual steps of a typical SPE sequence-i) conditioning of the sorbent, ii) application of the sample, iii) rinsing and cleaning of the sample, and iv) desorption and recovery of the analytes to be separated-can be performed sequentially for up to 24 cartridges at the same time using extraction units working under positive or negative pressure. The whole sequence can also be easily automated with devices now available by several companies using any comm e rcial cart ri d ges or ex t raction disks. Examples are the ASPEC from Gilson, Microlab from Hamilton, AutoTrace and RapidTrace from Zymark. Possibility exists for some of these devices for automatic injection of an aliquot of the final extract into the chromatographic system. The complete automation also exists which couples SPE with direct online LC analysis (ASPEC XL from Gilson, Prospekt from Spark Holland, OSP-2 from Merck). These last two apparatus improved productivity since the next sample is automatically prepared while the previous sample is being analyzed. Th e re fo re, method development can easily be automat e d with various degrees of automation.Off-line SPE materials are mainly disposable cartridges and disk membranes. Besides automation, two other main SPE characteristics have been commercially developed. The first one tends to increase the sample thoughput and the second one to broaden the polarity range of analytes to extract. R e s t ricted fl ow rates and cl ogging are often observe d when handling water containing suspended solids such as surface water. Various approaches have been developed to solve this problem. One consists in depth filters which can be placed above the cartridge or membrane extracti...

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“…The solid phase extraction of these analyres from water has been performed with silica, which is a well known example of a solid phase using adsorption mechanism. Some years ago, Graphitized Carbon Black (GCB) was studied as a selective adsorbent to extract organic compounds of varied chemical nature from water samples [11][12][13][14] and retention mechanisms on GCB columns have been fully discussed. The exact mechanism involved in the chromatographic process is not well defined.…”

Section: Introductionmentioning

confidence: 99%

On-line determination of bipyridylium herbicides in water by HPLC

Ibáñez

¹

,

Picó

²

,

Mañes

³

1997

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Key WordsColumn liquid chromatography Solid phase extraction Graphitized carbon black Diquat, paraquat and difenzoquat SummarySelective on-line solid phase extraction (SPE) and liquid chromatography determination (HPLC) of diquat, paraquat and difenzoquat from environmental water samples has been accomplished with Graphitized Carbon Black (GCB) as both extraction and analytical columns. The method involved passing of 50 mL of water through a cartridge filled with Carbograph. In the elution step, the herbicides were transferred from the cartridge to the analytical column (Hypercarb) by mean of a gradient of pH 3 aqueous solution of tetramethylammonium hydroxide (TMAOH) and ammonium sulphate and methanol. Hypercarb columns were found to give a low probability of false positives for bypiridylium herbicides and are very selective for polar compounds. Recovery was better than 80 %. The breakthrough volume was studied with distilled water spiked with the herbicides at various concentration levels (from 0.1 to 20 ktg L-I). The limits of quantification of the method were lower than 0.1 ktg L -1. The total analytical method was applied to surface waters from Torreblanca Nature Park (CasteU6, Spain).

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“…Their higher efficiency over C 18 silica for trapping polar pesticides have been extensively shown by the group of Di Corcia et al [1,[25][26][27][28]. GCB are not enough pressure resistant to be used in LC so that no data indicating the LC behaviour of solutes are available.…”

Section: Carbonaceous Sorbentsmentioning

confidence: 99%

Multiresidue solid-phase extraction for trace-analysis of pesticides and their metabolites in environmental water

Pichon¹

1998

View full text Add to dashboard Cite

Recent research on the fate and transformation of pesticides in the environment has pointed out the need for including more and more polar analytes in multiresidue analysis. Liquid chromatography have been shown to be suitable for mu l t i residue sep a ration of many compounds over a wide ra n ge of polarity without prev i o u s derivatization. Examples can be found in the literature, the most impressive one being the multiresidue separation of 72 pesticides in one run published by Di Corcia and Marchetti some time ago [1]. However, despite the advances in separation and quantifi c ation tech n i q u e s , no sample can be directly analyzed and a multiresidue extraction is a compulsory step in the analytical procedure.In recent years, enrichment of trace compounds on suitable sorbents has been shown to be an interesting alternative to LLE, and has now become a reliable and useful tool for sample handling. In addition, many modern pesticides and identified degra d ation products are fa i rly soluble in water and are therefore less amenable to solvent extraction. Automation and new trends in SPEThe solid-phase extraction (SPE) area has been very active these past years, certainly due to the now well-recognized trends for using solvent-free methods in environmental analytical laboratories and for its suitability to automation [2]. The four individual steps of a typical SPE sequence-i) conditioning of the sorbent, ii) application of the sample, iii) rinsing and cleaning of the sample, and iv) desorption and recovery of the analytes to be separated-can be performed sequentially for up to 24 cartridges at the same time using extraction units working under positive or negative pressure. The whole sequence can also be easily automated with devices now available by several companies using any comm e rcial cart ri d ges or ex t raction disks. Examples are the ASPEC from Gilson, Microlab from Hamilton, AutoTrace and RapidTrace from Zymark. Possibility exists for some of these devices for automatic injection of an aliquot of the final extract into the chromatographic system. The complete automation also exists which couples SPE with direct online LC analysis (ASPEC XL from Gilson, Prospekt from Spark Holland, OSP-2 from Merck). These last two apparatus improved productivity since the next sample is automatically prepared while the previous sample is being analyzed. Th e re fo re, method development can easily be automat e d with various degrees of automation.Off-line SPE materials are mainly disposable cartridges and disk membranes. Besides automation, two other main SPE characteristics have been commercially developed. The first one tends to increase the sample thoughput and the second one to broaden the polarity range of analytes to extract. R e s t ricted fl ow rates and cl ogging are often observe d when handling water containing suspended solids such as surface water. Various approaches have been developed to solve this problem. One consists in depth filters which can be placed above the cartridge or membrane extracti...

show abstract

Selective determination of phenols in water by a two-trap tandem extraction system followed by liquid chromatography

Cited by 58 publications

References 26 publications

Multiresidue solid-phase extraction for trace-analysis of pesticides and their metabolites in environmental water

Multiresidue solid-phase extraction for trace-analysis of pesticides and their metabolites in environmental water

On-line determination of bipyridylium herbicides in water by HPLC

Multiresidue solid-phase extraction for trace-analysis of pesticides and their metabolites in environmental water

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