1
|
Jørgensen MB, Nyemann PP, Haq IU, Christensen P, Pattison DI, Christensen JH. System stability and signal enhancement with analyte protectants: Gas chromatography analysis of oxygenated-polycyclic aromatic hydrocarbons. Talanta 2024; 272:125810. [PMID: 38387374 DOI: 10.1016/j.talanta.2024.125810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/24/2024]
Abstract
Matrix effects can affect detection limits, precision, and accuracy and lead to signal enhancement or suppression effects in gas chromatography analysis. Analyte protectants, such as shikimic acid and gluconolactone, can imitate the effect of matrix components and reduce the differences in matrix effect between samples. This study aimed to investigate the ability of analyte protectants to enhance gas chromatography detector signals of different oxygenated-polycyclic aromatic hydrocarbons. Addition of 100 μg L-1 shikimic acid and 200 μg L-1 gluconolactone effectively enhanced detector response of the investigated target compounds. Addition of a higher content of analyte protectants did not result in any further enhancement. It was found that between four and eleven consecutive injections of a standard solution with analyte protectants were required to obtain a stable compound response. The long-term signal stability was then maintained with subsequent injections, though an overall negative drift of the system was observed over the sequence of 200 investigated injections. Analysis of the actual sample matrix instead of standards in pure solvent, as presented in this study, could also be a way to minimize the required number of injections. Shikimic acid and gluconolactone were first and foremost able to enhance signals of oxygenated-polycyclic aromatic hydrocarbons with similar functional groups (hydroxyl) in their molecular structure. It can be relevant to consider alternative analyte protectants with different functional groups according to the type of target compounds investigated.
Collapse
Affiliation(s)
- Mathias B Jørgensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark; BIOFOS A/S, Refshalevej 250, 1432, København, Denmark; MSCi, Bøgesvinget 8, 2740, Skovlunde, Denmark
| | - Peter P Nyemann
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Inam U Haq
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Peter Christensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - David I Pattison
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Jan H Christensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
| |
Collapse
|
2
|
Aragón Á, Toledano RM, Gea S, Cortés JM, Vázquez AM, Villén J. Large volume injection in gas chromatography using the through oven transfer adsorption desorption interface operating under vacuum. Talanta 2014; 123:39-44. [PMID: 24725862 DOI: 10.1016/j.talanta.2014.01.064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/24/2014] [Accepted: 01/29/2014] [Indexed: 11/29/2022]
Abstract
The present work describes a modification of the Through Oven Transfer Adsorption Desorption (TOTAD) interface, consisting of coupling a vacuum system to reduce the consumption of the helium needed to totally remove the eluent for large volume injection (LVI) in gas chromatography (GC). Two different retention materials in the liner of the TOTAD interface were evaluated: Tenax TA, which was seen to be unsuitable for working under vacuum conditions, and polydimethylsiloxane (PDMS), which provided satisfactory repeatability as well as a good sensitivity. No variability was observed in the retention times in either case. Solutions containing organophosphorous pesticides in two different solvents, a polar (methanol/water) and a non-polar (hexane) solvent, were used to evaluate the modification. The vacuum system coupled to the TOTAD interface allowed up to 90% helium to be saved without affecting the performance.
Collapse
Affiliation(s)
- Álvaro Aragón
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Rosa M Toledano
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Sara Gea
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - José M Cortés
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain.
| | - Ana M Vázquez
- Facultad de Educación, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Jesús Villén
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| |
Collapse
|
3
|
Lu Y, Yao D, Chen C. 2-Hydrazinoquinoline as a Derivatization Agent for LC-MS-Based Metabolomic Investigation of Diabetic Ketoacidosis. Metabolites 2013; 3:993-1010. [PMID: 24958262 PMCID: PMC3937830 DOI: 10.3390/metabo3040993] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 09/21/2013] [Accepted: 10/10/2013] [Indexed: 01/13/2023] Open
Abstract
Short-chain carboxylic acids, aldehydes and ketones are products and regulators of many important metabolic pathways. Their levels in biofluids and tissues reflect the status of specific metabolic reactions, the homeostasis of the whole metabolic system and the wellbeing of a biological entity. In this study, the use of 2-hydrazinoquinoline (HQ) as a novel derivatization agent was explored and optimized for simultaneous liquid chromatography-mass spectrometry (LC-MS) analysis of carboxylic acids, aldehydes and ketones in biological samples. The formation of carboxylic acid derivative is attributed to the esterification reaction between HQ and a carboxyl group, while the production of aldehyde and ketone derivatives is through the formation of Schiff bases between HQ and a carbonyl group. The compatibility of HQ with biological samples was demonstrated by derivatizing urine, serum and liver extract samples. Using this HQ-based approach, the kinetics of type 1 diabetes-induced metabolic changes was characterized by the LC-MS-based metabolomic analysis of urine samples from streptozotocin (STZ)-treated mice. Subsequently, carboxylic acid, aldehyde and ketone metabolites associated with STZ-elicited disruption of nutrient and energy metabolism were conveniently identified and elucidated. Overall, HQ derivatization of carboxylic acids, aldehydes and ketones could serve as a useful tool for the LC-MS-based metabolomic investigation of endogenous metabolism.
Collapse
Affiliation(s)
- Yuwei Lu
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA.
| | - Dan Yao
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA.
| | - Chi Chen
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55108, USA.
| |
Collapse
|
4
|
Hyphenated liquid chromatography–gas chromatography technique: Recent evolution and applications. J Chromatogr A 2012; 1255:100-11. [DOI: 10.1016/j.chroma.2012.02.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 02/06/2012] [Accepted: 02/07/2012] [Indexed: 11/21/2022]
|
5
|
Electromembrane extraction combined with gas chromatography for quantification of tricyclic antidepressants in human body fluids. Anal Chim Acta 2012; 725:51-6. [DOI: 10.1016/j.aca.2012.02.048] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Revised: 02/27/2012] [Accepted: 02/29/2012] [Indexed: 11/22/2022]
|
6
|
Kaal ER, Kurano M, Geiβler M, Janssen HG. Hyphenation of aqueous liquid chromatography to pyrolysis-gas chromatography and mass spectrometry for the comprehensive characterization of water-soluble polymers. J Chromatogr A 2008; 1186:222-7. [DOI: 10.1016/j.chroma.2007.10.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 10/05/2007] [Accepted: 10/12/2007] [Indexed: 10/22/2022]
|
7
|
Morin-Couallier E, Bleton J, Lameloise ML, Tchapla A. Quantification of deformed peaks in capillary gas chromatography (CGC): Application to simultaneous analysis of free fatty acids and less polar compounds in aqueous distillery effluent. Anal Chim Acta 2007; 583:259-65. [PMID: 17386554 DOI: 10.1016/j.aca.2006.10.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 10/11/2006] [Accepted: 10/12/2006] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to find a simple and rapid method allowing the simultaneous quantification of some alcoholic fermentation inhibitors present in aqueous distillery effluent in order to evaluate its recycling properties. A capillary gas chromatography (CGC) method was tested for the quantification of both short chain fatty acids (acetic to hexanoic) and neutral compounds (butane 2,3-diol, 2-furaldehyde, phenyl-2-ethane1-ol). A polyvalent column coated with trifluoro-propyl-polysiloxane, allowing water injection, was tested and experiments were performed directly on untreated samples. During the development of the method, a deformation of acid peaks was observed; that could be explained by a secondary equilibrium, added to the chromatographic equilibrium. Although the acid peaks were deformed, calibration curves were produced and rigorously validated, proving that quantification is possible even when the best chromatographic conditions have not been achieved. Eventually, the method enabled the concentration of eight major fermentation inhibitors in distillery effluent to be measured.
Collapse
Affiliation(s)
- E Morin-Couallier
- ENSIA, UMR GENIAL, 1 avenue des Olympiades, 91744 Massy Cedex, France
| | | | | | | |
Collapse
|
8
|
Abstract
On-line coupled liquid chromatography-gas chromatography (LC-GC) is a powerful technique that combines the best features of LC and GC and is ideal for the analysis of complex samples. This review describes the unique features of on-line coupled LC-GC. The different interfaces and evaporation techniques are presented, along with their advantages and disadvantages. Guidelines are given for selecting a suitable LC-GC technique and representative applications are noted.
Collapse
Affiliation(s)
- Tuulia Hyötyläinen
- Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.
| | | |
Collapse
|
9
|
Ng LK. Analysis by gas chromatography/mass spectrometry of fatty acids and esters in alcoholic beverages and tobaccos. Anal Chim Acta 2002. [DOI: 10.1016/s0003-2670(01)01497-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
10
|
Claudel P, Dirninger N, Etiévant P. Effects of water on gas chromatographic column efficiency measurements applied to on-column injections of volatile aroma compounds. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20020401)25:5/6<365::aid-jssc365>3.0.co;2-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
11
|
Pocurull E, Biedermann M, Grob K. Introduction of large volumes of water-containing samples into a gas chromatograph. Improved retention of volatile solutes through the swing system. J Chromatogr A 2000; 876:135-45. [PMID: 10823509 DOI: 10.1016/s0021-9673(00)00147-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The swing system is designed for introducing large volumes of water-containing samples into a gas chromatograph. Sample evaporation and solvent-solute separation are performed in separate compartments. This widens the application range to compounds of higher volatility. Sample evaporation takes place in a hot chamber packed with Carbofrit. Solvent-solute separation is performed in a cascade of increasing powers of retention. While high boiling solutes are retained in an oven-thermostatted retaining precolumn, the more volatile components are retained by a packed bed of sorbents of increasing powers of retention situated in a programmed temperature vaporiser. For elution, the gas flow is reversed and the solutes are discharged from the heated packed bed through the retaining precolumn into the separation column.
Collapse
Affiliation(s)
- E Pocurull
- Rovira i Virgili University, Department of Analytical Chemistry and Organic Chemistry, Imperial Tarraco, Tarragona, Spain
| | | | | |
Collapse
|
12
|
Vreuls JJ, Louter AJ, Brinkman UA. On-line combination of aqueous-sample preparation and capillary gas chromatography. J Chromatogr A 1999; 856:279-314. [PMID: 10526793 DOI: 10.1016/s0021-9673(99)00432-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Methods currently in use to combine the preparation of aqueous samples on-line with capillary gas chromatography (GC) comprise heartcut-orientated reversed-phase liquid chromatography-GC and analyte-isolation-orientated analyte extraction-GC. These approaches either use techniques in which water is directly introduced onto the GC column, or an indirect approach in which water is eliminated, i.e., by solid-phase extraction, solid-phase microextraction or liquid-liquid extraction, prior to introduction of the analytes onto the GC column. The latter type of approach is much more successful and user-friendly, and many applications have been reported.
Collapse
Affiliation(s)
- J J Vreuls
- Vrije Universiteit, Department of Analytical Chemistry and Applied Spectroscopy, Amsterdam, The Netherlands.
| | | | | |
Collapse
|
13
|
Louter AJ, Vreuls JJ, Brinkman UA. On-line combination of aqueous-sample preparation and capillary gas chromatography. J Chromatogr A 1999; 842:391-426. [PMID: 10377972 DOI: 10.1016/s0021-9673(99)00211-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An overview is presented of methods currently in use to combine the preparation of aqueous samples on-line with capillary gas chromatography. Two approaches can be distinguished: heartcut-orientated reversed-phase liquid chromatography-gas chromatography (GC) and analyte-isolation-orientated analyte extraction-GC. These approaches either use techniques in which water is directly introduced onto the GC column, or an indirect approach in which water is eliminated, i.e., by solid-phase extraction, solid-phase microextraction or liquid-liquid extraction, prior to introduction of the analytes onto the GC column. The latter type of approach is much more successful and user friendly, and many applications have been reported.
Collapse
Affiliation(s)
- A J Louter
- Free University, Department of Analytical Chemistry and Applied Spectroscopy, HV Amsterdam, The Netherlands
| | | | | |
Collapse
|
14
|
López FJ, Beltran J, Forcada M, Hernández F. Comparison of simplified methods for pesticide residue analysis. Use of large-volume injection in capillary gas chromatography. J Chromatogr A 1998; 823:25-33. [PMID: 9818390 DOI: 10.1016/s0021-9673(98)00393-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The combination of manual and automated extraction procedures using low sample volumes (5-50 ml) with large-volume oncolumn injection (LVI) (200 microliters) in capillary gas chromatography with flame photometric detection (GC-FPD) has allowed the determination of 16 organophosphorus pesticides in clean water samples at the low ng l-1 level with an important simplification in the sample preparation step. A simple and fast offline liquid-liquid microextraction procedure (2-5 ml water/l ml methyl tert.-butyl ether) has been applied to spiked groundwater samples (containing 0.5 ng of each pesticide) with good recoveries (over 80%) and precision (better than 10%), giving detection limits between 5 and 100 ng l-1 using 200 microliters injections in the GC-FPD system. The application of an inline automated liquid-liquid microextraction-LVI-GC procedure (2 ml water/2 ml methyl tert.-butyl ether: injection of 200 microliters in GC-FPD) using the autosampler ASPEC XL led to lower recoveries (> 50%) as a result of the low efficiency for mixing organic and aqueous phases, although with very satisfactory coefficients of variation (lower than 7%) and detection limits between 20 and 200 ng l-1. Manual and automated solid-phase extraction procedures using the well known C18 cartridges and the new Oasis HLB have been applied to groundwater samples (5-50 ml) spiked with 1 ng of each pesticide. Results obtained for both the manual and the automated procedures were satisfactory (recoveries over 80%) and the limits of detection for 50 ml sample volume ranged from 1 to 6 ng l-1.
Collapse
Affiliation(s)
- F J López
- Experimental Science Department, University Jaume I, Castelló, Spain
| | | | | | | |
Collapse
|
15
|
Hyötyläinen T, Riekkola ML. Direct coupling of reversed-phase liquid chromatography to gas chromatography. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00539-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
16
|
Goosens EC, de Jong D, de Jong GJ, Brinkman UAT. On-line sample treatment—capillary gas chromatography. Chromatographia 1998. [DOI: 10.1007/bf02466538] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
17
|
Beltran J, López F, Forcada M, Hernández F. Microextraction procedures combined with large volume injection in capillary gas chromatography for the determination of pesticide residues in environmental aqueous samples. Anal Chim Acta 1997. [DOI: 10.1016/s0003-2670(97)00548-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
18
|
Biedermann M, Grob K, Wiedmer M. Polyimide for deactivating gas chromatography vaporising chambers and fixing packing materials. J Chromatogr A 1997. [DOI: 10.1016/s0021-9673(96)00861-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
19
|
Scholten AB, de Haan JW, Janssen HG, van de Ven LJM, Cramers CA. Deactivation of silica surfaces with a silanol-terminated polysiloxane; structural sharacterization by inverse gas chromatography and solid-state NMR. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jhrc.1240200104] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
20
|
On-Line Sample Handling Strategies. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0167-9244(97)80006-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
|
21
|
Mondello L, Dugo G, Bartle KD. On-line microbore high performance liquid chromatography-capillary gas chromatography for food and water analyses. A review. ACTA ACUST UNITED AC 1996. [DOI: 10.1002/(sici)1520-667x(1996)8:4<275::aid-mcs5>3.0.co;2-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
22
|
Barceló D, Hennion MC. On-line sample handling strategies for the trace-level determination of pesticides and their degradation products in environmental waters. Anal Chim Acta 1995. [DOI: 10.1016/0003-2670(95)00423-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
23
|
Grob K. Development of the transfer techniques for on-line high-performance liquid chromatography-capillary gas chromatography. J Chromatogr A 1995. [DOI: 10.1016/0021-9673(95)00094-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
24
|
|
25
|
Capillary GC with Selective Detection Using on-line Solid Phase Extraction and Liquid Chromatography Techniques. ACTA ACUST UNITED AC 1995. [DOI: 10.1007/978-3-662-01063-1_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
|
26
|
Use of an open-tubular trapping column as phase-switching interface in on-line coupled reversed-phase liquid chromatography—capillary gas chromatography. J Chromatogr A 1993. [DOI: 10.1016/0021-9673(93)80457-j] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
27
|
|
28
|
Grob K, Li Z. Introduction of water and water-containing solvent mixtures in capillary gas chromatography. J Chromatogr A 1989. [DOI: 10.1016/s0021-9673(00)91323-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
29
|
Grob K, Neukom H, Li Z. Introduction of water and water-containing solvent mixtures in capillary gas chromatography. J Chromatogr A 1989. [DOI: 10.1016/s0021-9673(00)91324-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
30
|
Grob K, Müller E. Introduction of water and water-containing solvent mixtures in capillary gas chromatography. J Chromatogr A 1989. [DOI: 10.1016/s0021-9673(00)91325-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
31
|
Coupled reversed-phase liquid chromatography—capillary gas chromatography for the determination of atrazine in water. J Chromatogr A 1989. [DOI: 10.1016/s0021-9673(00)91326-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|