On-line coupled supercritical fluid extraction and chromatography for the determination of thiolcarbamate herbicides in soil matrix

Yarita, Takashi; Nomura, Akihiro; Horimoto, Yoshiyuki; Gonda, Shigeo

doi:10.1016/0021-9673(96)00251-8

Cited by 14 publications

(8 citation statements)

References 15 publications

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“…The volume of the samples was determined by the ¯ow rate of the pump and the time required for collecting the sample. The pump used had a maximum ¯ow rate of 1.5 L min 21 , which dropped to 0.15±0.35 L min 21 when the 100 mg cartridges (mesh size, 60±100 mm) were used. The excess DNPH was removed by a cartridge ®lled with 300 mg of a cation exchange resin (Waters) prepared in-house.…”

Section: Prepstation-gc-npd Systemmentioning

confidence: 99%

“…The inlet temperature was kept at 200 ³C and the instrument was operated in the constant linear velocity mode. The temperature of the column at injection was 80 ³C, and was programmed to reach 200 ³C at 20 ³C min 21 , 250 ³C at 3³C min 21 and, ®nally, 280 ³C at 10 ³C min 21 . The detector temperature was 250 ³C.…”

Section: Prepstation-gc-npd Systemmentioning

confidence: 99%

“…The detector temperature was 250 ³C. The total helium gas ¯ow (make-up gaszcarrier) was maintained at 10.0 mL min 21 , the hydrogen gas ¯ow at 3.0 mL min 21 and the air ¯ow at 60.0 mL min 21 .…”

Section: Prepstation-gc-npd Systemmentioning

confidence: 99%

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The determination of carbonyl compounds in air using a robotic sampling preparation system integrated to a gas chromatograph with a nitrogen–phosphorus detector

Suliman

Soma

2000

J. Environ. Monitor.

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A totally automated solid phase extraction gas chromatography procedure was developed for the sampling and analysis of carbonyl compounds in air. In this system, two PrepStation modules were used, one for the preparation and elution of 2,4-dinitrophenylhydrazine silica cartridges, and the other for air sampling. The sample collected by the sampling module was eluted to an autosampler vial in the PrepStation module and then transferred to the gas chromatograph for analysis via a robotic arm. The sampling module was modified to enable air sampling via an external pump. A typical run by this technique required 142 min, 100 min for air sampling and 42 min for the other operations, including a GC analysis time of 25 min. Recoveries of at least 85% were obtained for all compounds studied. The detection limits for formaldehyde, acetaldehyde and acetone were 2.2, 2.7 and 2.2 ppbv, respectively. All operations, including the conditioning of the cartridges, were performed without any intervention from the analyst.

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Section: Prepstation-gc-npd Systemmentioning

confidence: 99%

Section: Prepstation-gc-npd Systemmentioning

confidence: 99%

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The determination of carbonyl compounds in air using a robotic sampling preparation system integrated to a gas chromatograph with a nitrogen–phosphorus detector

Suliman

Soma

2000

J. Environ. Monitor.

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“…However, excess of water is detrimental to the extraction, as polar compounds will rather partition into the water phase than in the fluid; this effect has been observed during the SFE of molinate from soils samples [13]. Besides, the solubility of water in CO 2 (0.3%) causes restrictor plugging by ice upon fluid depressurization as well as water carrying over into the collection system and ultimately into the chromatographic system.…”

Section: Preparation Of the Samplementioning

confidence: 99%

“…Alternatively, the SFE system may be coupled on-line with chromatographic systems, gas chromatography (GC), liquid chromatography (LC), or supercritical fluid chromatography (SFC), by means of an interface [5,8]. For example, the coupling of SFE and SFC e n abled the determ i n ation of thiolcarbamate herbicides (molinate and thiobencarb) from spiked soil samples (with organic content from 1.75 to 12.9%) [13]. Obviously, such a system seems very attractive when traces of pesticides are c o n s i d e re d, as it avoids possible losses or contaminat i o n ; however, it affords less flexibility than the off-line coupling, so its use remains uncommon.…”

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confidence: 99%

Supercritical fluid extraction as a use-ful method for pesticides determination

Camel¹

1998

Analusis

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Despite attractive features (rapid extractions, small solvent volumes, non-toxicity of CO 2 , potential of selectivity depending on the fluid density, relatively clear and concentrated ex t ra c t s , p o s s i ble coupling with ch romatography and automation), the use of SFE in routine analytical ap p l i c ations is a rather slow process. Indeed, t h e major drawback of this recent technique is the large number of parameters to control and optimize, which results in time re q u i red for developing a new method. In add i t i o n , t h e extraction conditions are strongly dependent on the matrix to be extracted, so that parameters need to be adjusted for every new application. D e t e rm i n ation of pesticides remains a ch a l l e n ge fo r mainly three reasons: the wide variety of physicochemical properties and chemical structures of pesticides, the many possible matrices that should be investigated, and the trace c o n c e n t rations at wh i ch pesticides are usually pre s e n t . Recent papers reviewed environmental applications of SFE [1,2], especially with regards to the extraction of the main classes of pesticides [3][4][5]. As SFE perfo rmances are strongly dependent on the nature of the sample, this article will consider the matrices that have been submitted to SFE for pesticides determination. Principle of SFEA fluid is in its supercritical state when both its pressure and temperature are above their critical value (when only one c ritical value is at t a i n e d, the fluid is said subcri t i c a l ) . Supercritical fluids possess unique properties, intermediate between gas and liquids properties [6][7][8][9][10]. In particular, their high diffusivity allows for rapid extractions. In addition, the fluid density may be precisely adjusted, by a correct choice of both pressure and temperature.The key parts of an SFE system are the high-pressure pump wh i ch delive rs the fl u i d, and the re s t rictor wh i ch maintains the pressure inside the system. Extraction is performed inside a high-pressure cell (containing the sample), maintained at the correct temperature. The fluid may simply fill the cell (static mode), or continuously flow through the vessel (dynamic mode). The extracted solutes are entrained by the supercritical fluid flow out of the cell; their collection is usually achieved as the fluid is depressurized by passing through the restrictor. The collected solutes are further analyzed using gas or liquid chromatography. Also, a few recent studies report the use of enzyme immunoassay as a rapid screening process [5,11,12]. Alternatively, the SFE system may be coupled on-line with chromatographic systems, gas chromatography (GC), liquid chromatography (LC), or supercritical fluid chromatography (SFC), by means of an interface [5,8]. For example, the coupling of SFE and SFC e n abled the determ i n ation of thiolcarbamate herbicides (molinate and thiobencarb) from spiked soil samples (with organic content from 1.75 to 12.9%) [13]. Obviously, such a system seems very attractive when traces of pest...

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Supercritical fluid extraction coupled to packed column supercritical fluid chromatography

Anderson¹

1998

Analytical Supercritical Fluid Extraction Techniques

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On-line coupled supercritical fluid extraction and chromatography for the determination of thiolcarbamate herbicides in soil matrix

Cited by 14 publications

References 15 publications

The determination of carbonyl compounds in air using a robotic sampling preparation system integrated to a gas chromatograph with a nitrogen–phosphorus detector

The determination of carbonyl compounds in air using a robotic sampling preparation system integrated to a gas chromatograph with a nitrogen–phosphorus detector

Supercritical fluid extraction as a use-ful method for pesticides determination

Supercritical fluid extraction coupled to packed column supercritical fluid chromatography

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