Focusing Review

Chromatography, Vol.24 No.1 (2003)

Focusing Review

Miniaturization of Separation Systems and Its Applications
Yoshihiro Saito
School of Materials Science, Toyohashi University of Technology
Toyohashi 441−8580, Japan.
Received December 25, 2002. Revised manuscript received January 8, 2003. Accepted January 14, 2003

Abstract
Development of miniaturized separation system consisted of microscale extraction and liquid phase separation processes has been reviewed.
Various types of novel bonded stationary phases have been developed on the basis of the systematic analysis for the retention behavior ofpolycyclic aromatic hydrocarbons on experimentally synthesized phases. In this review, the miniaturization of microscale sample preparation
technique and the effective on−line coupling to microcolumn liquid phase separations are also described especially focusing on the approachby the author’s group. The novel use of synthetic polymer filaments as the stationary phase and extraction media in those microscale separation systems will be introduced along with the applications in gas chromatographic separation.
Keywords: miniaturization; sample preparation; microcolumn; on−line coupling; fibrous materials; liquid chromatography; gas chromatography

In this article, several recent results, especially on the mini-

1. Introduction
Miniaturization of separation systems has been increasingly

aturization of separation columns in liquid chromatography and ex-

focused because it must provide a promising solution to the recent

traction cartridges in sample preparation process will be briefly re-requirements such as high performance, rapid analysis with a re-viewed. Novel use of fibrous materials in microscale separation

duced running cost and without environmental pollution [1−4].

systems, as a separation medium and an extraction medium, will be

Down−sizing of the separation columns is also one of the most ef-

also described along with some applications for the analysis of real

fective approach to develop novel stationary phases in liquid chro-complex sample mixtures.

matography (LC) because the evaluation of the limited amount of
2. Miniaturization of Columns in Liquid Chromatography

experimentally synthesized stationary phases could be accomplished [5,6]. With microscale LC the characteristics of commer-

On the successful applications in wide scientific fields, LC

cially available stationary phases such as octadecylsilicas (ODSs)

method has been recognized as one of the most powerful and ver-have been investigated, and various novel bonded stationary phases

satile separation techniques. In contrast to the wide applicability,

have been synthesized and evaluated based on the systematic

however, there is still a long way to explain the whole separation

analysis of the retention behaviors of probe solutes on those con-mechanism in LC, because many parameters are controlling theventional stationary phases [7−29]. To realize the miniaturizedmolecular recognition in the chromatographic process. A large por-separation system, the development of microscale sample prepara-tion of LC separations in reversed−phase (RP) conditions havetion process can be regarded as a key innovation in separation sci-been carried out with commercially available ODS phases, andence. However, the reports for the miniaturized sample preparation

those phases could be basically divided into two types depending

technique, which was specially designed for microscale separationon the bonding chemistry: one is polymeric, which is typically syn-systems, have been still limited mainly because of the complexity

thesized with trifunctional silanes as the starting material in aque-and difficulties for the on−line coupling and the operation [1,2].

ous synthetic conditions, and another is monomeric synthesized

TEL: +81−532−44−6803, FAX: +81−532−48−5833
E−mail: saito@chrom.tutms.tut.ac.jp―７―Chromatography, Vol.24 No.1 (2003)

from monofunctional silanes in non−aqueous conditions. Althoughbonded stationary phases based on the molecular shape recognition

the correlation between the synthetic methods and the selectivities

concept in chromatographic process [36,37]. Taking advantage ofhas been reported [30−35], the theoretical interpretation for the mo-the miniaturized system, these experimentally synthesized phases,

lecular−molecular interaction between solute molecule and bonded

as illustrated in Figure 2, have been chromatographically character-phase ligand(s) has not been well established, mainly due to theized by the systematic investigation using polycyclic aromatic hy-

difficulties in the surface characterization of these ODS stationary

drocarbons (PAHs) and fullerenes as the solute molecules. Al-phases in real chromatographic conditions. However, various novel

though the PAHs have many structural isomers, these relatively

bonded phases have been synthesized and introduced as the station-

simple molecular structures than real samples to be separated in LC

ary phases by the recent innovations in synthetic and bonding

applications are quite suitable for the systematic analysis of thechemistries [7−23]. Since the design of these novel phases, having

separation mechanism based on the molecular shape recognitiona desirable separation characteristics and performance, could be ac-concept. In addition the combination of the results obtained fromcomplished by the systematic analysis of retention behaviors of ex-

the retention behavior studies for PAHs with that from fullerenes

perimentally synthesized phases of a limited amount, it can be said

could offer more systematic and comprehensive interpretations

that microcolumn separation is a most powerful and inevitable

about molecular shape recognition process on the stationary phase,technique during the bonded phase developments.

because the fullerene molecules, such as C60 and C70, can be re-Figure 1 shows typical microcolumns prepared by fused−sil-garded as very large PAHs with specific shape and size [9,37]. In-

ica capillaries of 0.32 and 0.53 mm i.d. These columns can be

troducing these spherical model solutes, it has been confirmed thatpacked with a preliminary stationary phase of less than 50 mg by a

the interval of the bonded ligands on the silica gel support and theslurry method and operated with a typical flow−rate of less than 10ordering of these bonded ligands play a role to generate an effec-

to 20 µL/min, indicating the advantageous features of the mi-tive interaction with the solute molecules [25−27]. From the reten-

croscale separation [5,6]. The introduction of microcolumn LC sys-

tion behaviors of these sample probes on various multi−legged andtem also enables the use of valuable solutes as the sample probes

C60 bonded phases, it has been also demonstrated that an interactive[36].

structure of the bonded ligand on the support surface can be well−Jinno and Saito et al . designed several groups of novel

designed by the introduction of novel synthetic reactions to the

Figure 1. Illustrations of typical laboratory made microcolumns for bonded phase evaluation. A) 0.53 mm i.d. andB) 0.32 mm i.d.

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Yoshihiro Saito

Figure 2. Novel stationary phases synthesized by the molecular shape recognition concept. A) alkyl, alkyldiphenyl andtriphenyl bonded phases; B) phenylpropyl and methoxylated phenylpropyl bonded phases; C) multi−legged
phenyl bonded phases; D) liquid−crystal bonded phases and E) C60 bonded phase.

―９―Chromatography, Vol.24 No.1 (2003)

bonded phase preparation.
3. Miniaturization of Sample Preparation Device for Liquid
Phase Separations
3.1 Coupling of SPME and micro−LC
As a microscale sample preparation method for the analysis ofvolatile and semi−volatile compounds in gas chromatography(GC), Pawliszyn et al. developed solid−phase microextraction(SPME) [38−40]. In the SPME method, a fused−silica rod with apolymeric coating on the surface is employed as the medium forthe extraction of volatile analytes from aqueous sample solution or
the headspace of the sample solution. Desorption of extracted analytes can be made with the heating of the SPME fiber in a conventional GC injection port, allowing the SPME device to have a goodcompatibility with GC system. In order to apply the SPME method
for the analysis of non−volatile and/or thermally labile compounds,
however, a specially designed desorption device is needed to accomplish the coupling of the SPME to liquid−phase separation systems, such as LC [41−47], supercritical fluid chromatography(SFC) [48,49], capillary electrophoresis (CE) [50] and micellar
electrokinetic chromatography (MEKC) [51,52]. As the desorption
interface between SPME and micro−LC, Jinno and Saito et al . [44−47] developed a desorption device (Figure 3), where a modified T−shape connector was combined with a union and several tubes
having an appropriate size in order to maximize the desorption performance and the compatibility to microscale separation systems,
but to minimize undesirable void volume in the device. The SPME
fiber is inserted from the top of the desorption interface and a small
amount of the desorption solvent is supplied from the port positioned just above the inserted SPME fiber using a micro−flowpump. The desorbed analytes are transferred to the loop of the LC
Figure 3. Specially designed desorption interface for the coupling of SPME and micro−LC.

injector. For the desorption by the flow of the LC mobile phase ora highly pressurized fluid, such as supercritical fluid (SF), othertypes of desorption interface have been developed by Salleh et al .
and Pawliszyn et al . to accomplish the desorption under the pres-course were determined successfully, indicating the powerful pre-surized conditions [48,49].

concentration ability [44].

With the desorption interface shown in Figure 3, the determi-

The determination of pharmaceutical compounds in biologicalnation of common pesticides in environmental water samples has

fluids has also demonstrated with the desorption interface, wherebeen reported [44]. The effect of the extraction conditions, such as

the extraction of benzodiazepines and tricyclic antidepressantsthe type of the fiber coating, the extraction time and temperature,(TCAs) from human urine samples by SPME and the separation in

the effect of the agitation have been investigated along with the ef-

micro−LC have been reported [47]. Although the extraction power

fect of additives into the sample matrix to improve the extraction

for each TCAs with a SPME fiber is different mainly due to the po-

efficiency of the analytes. The desorption conditions, such as thelarity, a good extraction performance was demonstrated for thetype of desorption solvent, the flow−rate for dynamic desorption

analysis of human urine samples, and the detection limits for com-and the desorption time have been also systematically studied tak-mon TCA drugs such as amitriptyline, nortriptyline and imi-

ing into account an effective on−line coupling with subsequent LC

pramine, were determined to be at ng/mL level, showing a quite ac-

separation process. After the preliminary optimization process, 10

ceptable detection performance in clinical and forensic situations.

pesticides in surface water samples obtained near a local golf

The total solvent consumption in this particular example was less

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Chromatography, Vol.24 No.1 (2003)

Yoshihiro Saito

than 1.5 mL even including the mobile phase required for the mi-

ing material contacting the sample solution is maintained as samecro−LC separation.

as the vacant capillary having the same dimensions. After the insertion of the stainless wire of 0.20 mm o.d., the internal volume ofthe extraction capillary was reduced from 19.6 µL to 7.1 µL for the

3.2 In−tube SPME and wire−in−tube SPME as the microscale
sample preparation method

capillary of 0.25 mm i.d. x 40 cm, producing the phase ratio

Introducing a short section of open−tubular GC column as thechanged from about 500 to 180 with a polymeric coating of 0.25

extraction device, in−tube SPME method has been developed byµm thickness [63,64]. In the wire−in−tube configuration, more ef-

Pawliszyn et al . for an effective on−line coupling of sample prepa-

fective extraction could be obtained and more efficient on−line

ration and LC separation [53,54]. The automation of the hyphen-coupling of the extraction process to subsequent microcolumn

ated analytical system has been also reported for the analysis ofseparation process has been established. With this modification it

various classes of compounds in complex matrices [55−58]. In ad-

was reported that the successful applications for environmental

dition to several commercially available coatings used widely as

analysis such as determination of phthalates in surface and waste

GC stationary phases, novel polymeric coating materials have beenwater samples [63,64], and for biological analysis such as determi-

developed for a selective extraction [59−61], however, the extrac-

nation of TCAs in biological fluids [62]. The results also demon-tion efficiency of the in−tube method is generally lower than thatstrated that more effective preconcentration than the conventionalcan be obtained with conventional solid phase extraction (SPE)in−tube SPME method could be accomplished with this modifica-

method. This is mainly due to the large phase ratio between thetion, and that the hyphenated system consisted of wire−in−tube“solid phase” (viscous polymeric material on the inner capillary

SPME and micro−LC should present a great potential for the fastsurface) and the “liquid phase” (aqueous sample solution passed

analysis of various organic compounds in other complex sample

through the capillary), and therefore, the extraction should be re-matrices.

peatedly carried out with pumping the sample solution by so−
3.3 Fiber−in−tube SPE: a novel use of polymer filaments as thecalled “draw/eject” procedures [53−58] to get an improved extrac-

extraction medium

tion efficiency.
Based on the above results with in−tube SPME, Saito et al .

More recently, the use of polymer filaments as the extraction

have developed wire−in−tube SPME [62] by inserting a stainlessmedium has been also reported. The novel technique, fiber−in−steel wire into the extraction capillary in in−tube SPME. As showntube SPE (FIT−SPE) [65], where several hundreds of fine fila-in Figure 4, the internal volume of the extraction capillary could bements of polymeric material are packed longitudinally into a shortsignificantly reduced while the surface area of the polymeric coat-

capillary of polyetheretherketone (PEEK) or polytetrafluoroethylene (PTFE), has been developed on the basis of the successful applications of wire−in−tube extraction. Not only significantly reducethe internal void volume of the extraction capillary (Figure 4),
those fine polymer filaments can also be employed as the extraction medium. A rigid−rod heterocyclic polymer, Zylon (Toyobo,
Ohtsu, Japan) was firstly chosen [66] taking into account its chemical structure, the solvent resistance for the mobile phase and mechanical strength during the packing process of the fiber, althougha certain effectiveness of other several solvent− and heat−resistantfibers was confirmed for the extraction of other class of compounds[67]. For the preparation of the extraction tube, the fiber was typically cut to 100−mm length and packed longitudinally into thesame length of PEEK tube (0.25 mm i.d., 1/16" o.d.). The diameterof each filament of the fiber is about 11.5 µm and the typical number of the filaments packed in the PEEK tubing of 0.25 mm i.d. isabout 310. Because of the parallel arrangement of the filaments tothe outer tubing, a number of coaxial narrow channels have been
formed parallel to the axis of the capillary therein. Therefore, theFigure 4. Schematic representation of three types of extraction
capillary [63]. A) In−tube; B) wire−in−tube; C) fiber−in−tube.

FIT−SPE device shows a reduced pressure drop during the extraction and desorption comparing with conventional SPE cartridge,―１１―Chromatography, Vol.24 No.1 (2003)

4. Miniaturized Separation System Using Novel Fibrous Mate-and also the undesirable plugging from insoluble and/or particulaterialsmaterials in real sample matrices can be significantly reduced in

4.1 Miniaturized FIT−SPE for microcolumn separations

the FIT format.

Further miniaturization of the extraction tube has been dem-

In the developed FIT−SPE/LC method [65], the extraction
capillary is installed between the switching valve and the injection

onstrated by Saito and Jinno et al . [67,68] for the direct coupling

valve, and two syringe pumps (one for sample solution and anotherof FIT−SPE to packed capillary LC. Figure 5 shows the miniatur-for desorption solvent) are connected to the switching valve. For

ized FIT−SPE cartridge installed in the rotor of the Rheodyne

the extraction, the sample solution was pumped through the extrac-

Model 7520 micro−injector (Rheodyne, Cotati, CA, USA) [67].

tion tube by one of the syringe pumps, typically at the flow−rate of

The flow channel for the sample loading (the center hole in the ro-

10 to 50 µL/min. After changing the position of the switchingtor) was enlarged and the FIT cartridge was inserted therein. The

valve, a certain volume of the desorption solvent was also pumped

extraction cartridge was prepared with a PEEK tube of 0.50 mm

by another syringe pump to desorb the extracted analytes and si-

i.d. x 5.0 mm packed with Zylon

multaneously transfer them into the sample loop of the injection

similar manner as described above. The miniaturized extraction

valve. The successful quantification of di−2−ethylhexyl phthalate

cartridge was then sandwiched by two pieces of short blank PEEK

(DEHP) in waste water samples has been reported with the FIT−

capillaries, and installed into the hole in the modified rotor. Insert-

SPE tubing of 0.25 mm i.d. x 10−cm length [65], showing theing appropriate size of several PEEK capillaries to other flow−

powerful sample preparation performance for complex sample ma-channels in the valve, the injector was further modified to reduce

trices.

any undesirable extra void volume.

of about 1500 filaments in a

It has been also demonstrated that an effective interaction of

In the extraction process, the sample solution from a syringe

the sample solution with a number of the fine fibrous extraction

pump is passed through the extraction cartridge, while the analytes

media in the extraction capillary could enable itself to be further

in the sample solution are extracted onto the packed filaments.

miniaturized as a microscale sample preconcentration device.

Next, the position of the injector is changed to “desorption/injec-

Down−sizing of the extraction device also allows the direct cou-tion” to make desorption and injection simultaneously by the mo-pling of the extraction process with microcolumn separation meth-bile phase flow for micro−LC separation. Therefore it can be said

ods, but without any disadvantages such as over−loading duringthat no desorption solvent is needed for the sample preparation

sample injection and poor resolution in the chromatographic sepa-

process. As the same as longer FIT capillary, the mini−cartridge

rations.

can be prepared with a good reproducibility, and these cartridges
also have a good stability for repeatable use, normally more thanFigure 5. Miniaturized FIT−SPE cartridge installed in modified Rheodyne 7520 microinjector.

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Yoshihiro Saito

50 runs without any significant problems, such as an increase in thepared with a short section of a GC column (DB−5, 5%−phenyl−pressure drop over the cartridge and a decrease in the extraction

95%−methyl−polysiloxane; J & W Scientific, Folsom, CA, USA)power. In case, the extraction performance was slightly decreased

and fibrous (250 filaments of Zylon ) packing materials. For theafter the sequential sample extraction of more than 50 times, a sim-

analysis of TCAs in human urine, the sample solution was continu-

ple washing and/or re−conditioning processes using an organic sol-ously supplied from the syringe, typically at the flow−rate of 80 µL

vent could be employed to make sure the reproducible results dur-/min for 12.5 min (i.e. the total sample volume pumped was 1.0

ing the next 50 consecutive runs. With a LC separation using amL) during the extraction process. Next, the syringe was replaced

packed capillary column of 0.53 mm i.d x 20 cm, the total solvent

by another syringe containing acetonitrile as the desorption solvent.

volume required for the typical analysis of phthalates in a waste

By pumping an appropriate volume of the solvent, the desorbed

water sample is less than 40 µL even including the solvent as theanalytes were transferred to the space in the modified cross connec-

mobile phase component [67].

tor. When the zone containing the desorbed analytes was reached

For the on−line coupling of the fiber−in−tube SPME to elec-

to the cross section of the separation capillary, the separation was

trokinetic separation methods, two types of laboratory−made inter-

started by applying the voltage. The volume of the desorption sol-faces, shown in Figure 6, have been developed [69]. Figure 6 A

vent and the flow−rate could be optimized easily in simple prelimi-

shows the overview of the FIT−SPE/CE system and the close−upnary experiments. Combining the inner−coated capillary and fi-of the specially designed extraction capillary installed in a modi-

brous packings, an improved extraction power was obtained for the

fied cross−connector [69,70]. The extraction capillary was pre-mixture of TCAs having different polarity. The volume of required
solvent was less than about 2.0 µL for each run and, typical preconcentration factor of more than 200 times was demonstrated withthe total sample volume of 1.0 mL and the extraction time of about
10 min [70].
On−line coupled FIT−SPE/CEC system was also developedwith the “in−valve” configuration depicted in Figure 6 B, where acommercially available 4−port 2−way valve (Model HV 4−1,
Hamilton, Reno, NV, USA) was employed as an interface housing[68,69]. About 380 pieces of Zylon filaments were packed (packing density was about 80%) longitudinally into a PTFE tubing of0.25 mm i.d. x 5.0 mm, and then the tube was installed into the rotor of the valve as the miniaturized extraction cartridge. As can beseen from the structure, no desorption solvent is needed for the
sample preparation process, and the calculated preconcentration
factors for the typical phthalates in aqueous samples were morethan 60 for the extraction of 20−µL sample volume (at the flow−rate of 4 µL/min for 5 min). The total volume of the organic solvent for each analysis was only about 2.5 µL as the mobile phasecomponent for most of the applications such as the analysis ofphthalate mixtures in water samples [68].
4.2 Fibrous stationary phases for microcolumn separations
The possibility of the fibrous stationary phase in LC was reported more than a decade ago [71−74]. In these studies, it was
shown that the fibrous materials might have a possibility to be anovel stationary phase in liquid−phase separations, although the efficiency was not sufficient as a column for LC separation. Taking
an advantage of the flat−flow profile of CEC, recently, a better
separation performance over LC was obtained with the fiber−
packed column having the effective length of only 50 mm. As the

Figure 6. System overview of FIT−SPE/CE (A) and FIT−SPE/
CEC (B). (Reproduced from reference [69])fibrous materials, synthetic fibers such as Zylon and Kevlar (Du―１３―

Chromatography, Vol.24 No.1 (2003)

ber−packed columns.

Pont−Toray Co., Ltd., Tokyo, Japan) were also introduced to prepare the columns [75], and rapid separation of aromatic compounds

4.3 Polymer−coated fibrous materials for miniaturized separa-

has been demonstrated without frits that might be an origin of bub-tion systems

ble formation. Therefore, it can be considered that the fiber−packed

Polymer−coating with typical GC stationary phases (liquid

capillary may have a wide application as a separation media inphases) onto the packed filaments has been also investigated to de-

CEC without the requirements for bubble elimination techniques.
Successful introduction of the fibrous stationary phases wasvelop the stationary phase in short column GC separation and thedemonstrated not only in liquid−phase separations but also in gas−

extraction medium in miniaturized sample preparation process. The

phase separations [76]. About 330 and 600 filaments of heat resis-

study was originally started to confirm the contribution of thetant polymers were packed longitudinally into fused−silica capillar-

chemical structure of different fibrous materials and the coatings

ies of 0.32 and 0.53 mm i.d., respectively, and the separation of

toward the separation and extraction performances. As expected,

several test mixtures, such as n−alkanes, was carried out with these

the separation characteristics can be tuned with different types offiber−packed capillary columns in GC. Figure 7 shows typicalpolymeric coating onto the packed fibers [76], although the com-cross−section photograph of a fiber−packed GC capillary column.

patibility of the polymeric materials to the fibrous materials should

The separation of alkylbenzenes, alkanes, alcohols and PAHs has

be systematically studied more. The results also showed that the re-been carried out and the data demonstrated that the fibrous station-

tentions for solutes were significantly increased with the polymericary phase has a function as the stationary phase for the GC analysis

coating onto the packed−fibers. The coating on the fiber surfaceof volatile compounds, although the difference in retention power

was very stable for the solvent washing, for example, even after the

between different fibrous stationary phases should be further inves-column washing with 20 mL of acetone, a slight decrease in the re-tigated. The linear relationship between the carbon number of thesetention time (less than 4 % for all solutes) was only observed once,

homologous mixtures and the corresponding logarithmic retention

and no further retentivity was decreased with subsequent solvent

factors was observed, indicating that temperature−programmed

washing. Therefore, as can be seen from the typical chromatogram

separation with these fiber−packed columns could be a powerful

illustrated in Figure 8, it is quite clear that the packed−fibers have atool even for the low−volatile compounds having a higher boilingfunction as the support for the coating as well as the stationary

point [76]. The results also demonstrated that the fiber−packed col-phase itself, because a conventional wall−coated capillary with theumns possessed the practical sample loading capacity over a con-same size and coating reagent do not show any measurable reten-

ventional open−tubular capillary column. Actually, an increasedtion for the same analytes in the same separation conditions.

sensitivity was obtained especially for low−volatile compounds be-

The extraction power of the fiber−packed capillary was also

cause no splitter should be needed for most of the separations on fi-

significantly improved with the polymeric coating [77,78]. The extraction efficiencies for the standard solution containing 1.0 ng/mLeach di−n−hexyl phthalate (DHP) and DEHP with the polymer−
coated fiber−packed capillary (coated with HR−52, 5%−phenyl−
95%−methyl−polysiloxane; Shinwa Chemical, Kyoto, Japan) wereabout 63 and 101 %, respectively; while the extraction efficiencies
with non−polymer−coated type were 20 and 21 %, respectively[78]. The results are quite consistent with the results obtained within−tube SPME method, where different extraction characteristics
are reported with different types of polymeric coatings to the capillary wall [64,70]. Comparing with non−coated fiber−packed capillary, the extraction efficiency obtained with coated one was dramatically improved, especially for DEHP, which was quantitatively
extracted [77]. The trend has a good agreement with the results inthe previous investigations, where a good correlation between thehydrophobicity of the analyte and the extraction efficiency was
found for the extraction by fiber−packed extraction media [66,67].
Although the contribution of the chemical structure and the polarityof the polymeric coating should be investigated more, the results

Figure 7. SEM image of the cross−section of fiber−packed capillary GC column (0.53 mm i.d.).

indicated the excellent suitability of the HR−52 coating for the―１
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Yoshihiro Saito

fields in separation science, especially for the trace amount of theanalytes in complex mixtures such as environmental and biologicalsamples.
The applications of polymer−coated and surface−derivatizedfibrous materials in miniaturized sample preparation process are
currently being studied as well as the employment of similar fibrous separation media as the new format of the stationary phasematerials in various chromatographic techniques. Novel fibrous extraction/separation media having different chemical structures anddifferent functionalities on the surface can be specially designed in
the near future based on the concept of molecular shape recognition.
6. Acknowledgements
The author would like to thank Prof. Kiyokatsu Jinno, Prof.
Yukio Hirata, Dr. Hatsuichi Ohta, and all other collaborators in
Separation Science Laboratory, School of Materials Science, Toyohashi University of Technology for their valuable suggestions andFigure 8. Typical chromatogram for the separation of alkylbenzenes on a polymer−coated fiber−packed capillarycolumn. Conditions: column, fused−silica (0.32 mm i.
d. x 2 m) packed with HR−1 (polydimethylsiloxane;
Shinwa Chemical) coated Zylon ; packing density,
18 %; carrier gas, N2; column inlet pressure, 10 kPa;
N2 flow−rate, 1 mL/min; column temperature, 50℃(1.5 min) to 230℃ at 5 deg/min; injection and detection temperature, 250℃. Injection (1 µL of standard
sample containing 0.1 % each of alkylbenzenes in CH2
Cl2) was made with splitless mode.

assistance during this project. The author also expresses his deep
gratitude to the following individuals: Prof. E. S. Yeung (AmesLaboratory/Iowa State University), Dr. F. J. Yang (Micro−Tech
Scientific), Prof. H. Nagashima (Kyushu University), Prof. T.
Takeuchi (Gifu University), Prof. Y. Shimizu (The University of
Shiga Prefecture), Dr. M. Okamoto (Gifu Prefectural Tajimi Hospital), Prof. M. Hayashida (Nippon Medical School), Profs. T.
Takeichi and Y. Kiso (Toyohashi University of Technology), Prof.
J. J. Pesek (San Jose State University), Dr. Y.−L. Chen (J & W Scientific), Dr. J. C. Fetzer (Chevron Research and Technology Company), Mr. Y. Ohtsu and Mr. Y. Kadota (Shiseido), Dr. T. Maeda

quantitative extraction of DEHP from aqueous sample matrix. The(National Metrology Institute of Japan), Dr. N. Nagae (Nomura

lowest limits of quantification for DEHP in waste water was 0.10

Chemical), Dr. H. Wada, Mr. K. Kotera, Mr. H. Matsuura and Dr.

ng/mL; while the data obtained by the fiber−packed extraction cap-

H. Kanehara (Shinwa Chemical Industries, Ltd.) and Mr. Y.

illary (without polymer−coating) was 0.50 ng/mL [77].

Nomura (Toyobo Co., Ltd.). A part of this work has been finan-

The polymer−coated fiber−packed capillary was further ap-

cially supported by Grant−in−Aid for Young Scientists ((B) No.

plied as the sample preparation medium for biological samples. As

13740421) from The Ministry of Education, Culture, Sports, Sci-a typical analysis of biological matrix, a successful sample prepara-ence and Technology (MEXT), and a Research Grant for Youngtion for the determination of TCA drugs in urine samples has been

Faculties from Toyohashi University of Technology. Financial sup-demonstrated [78], where the lowest limit of quantification was

ports from The Tatematsu Foundation and The Ogasawara Founda-quite acceptable (less than 2.0 ng/mL) for the analysis of TCAs intion for the Promotion of Science and Engineering are also ac-

clinical and forensic situations.

knowledged.

5. Conclusions

7. References

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Nakao, K. Hatano, M. Hayashida and K. Jinno, Anal. Sci.,tion of microscale sample preparation and microscale liquid phase18, 7−17 (2002).
[3]

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