Techniques and procedures for preparation of aquatic samples for chromatographic analyses

Onuska, Francis I.

doi:10.1002/jhrc.1240120103

Cited by 35 publications

(6 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Besides, the operation procedure is time-consuming and laborious. Therefore, techniques aimed at overcoming these drawbacks have been developed, for example, flow injection extraction (FIE), 2,3 solid-phase extraction (SPE), 4,5 and solid-phase microextraction (SPME). [6][7][8] FIE was first described in 1978 independently by Karlberg and Thelander 2 and by Bergamin et al 9 In the conventional FIE procedure, the sample is injected into aqueous carrier stream that is merged with suitable reagent streams.…”

Section: Introductionmentioning

confidence: 99%

Automation of Liquid–Liquid Extraction–Spectrophotometry Using Prolonged Pseudo-Liquid Drops and Handheld CCD for Speciation of Cr(VI) and Cr(III) in Water Samples

et al. 2005

View full text Add to dashboard Cite

A simple spectrophotometric system, based on a prolonged pseudo-liquid drop device as an optical cell and a handheld charge coupled device (CCD) as a detector, was constructed for automatic liquid-liquid extraction and spectrophotometric speciation of trace Cr(VI) and Cr(III) in water samples. A tungsten halogen lamp was used as the light source, and a laboratory-constructed T-tube with two open ends was used to form the prolonged pseudo-liquid drop inside the tube. In the medium of perchloric acid solution, Cr(VI) reacted with 1,5-diphenylcarbazide (DPC); the formed complex was automatically extracted into n-pentanol, with a preconcentration ratio of about 5. The organic phase with extracted chromium complex was then pumped through the optical cell for absorbance measurement at 548 nm. Under optimal conditions, the calibration curve was linear in the range of 7.5 -350 µg L -1 , with a correlation coefficient of 0.9993. The limit of detection (3σ) was 7.5 µg L -1 . That Cr(III) species cannot react with DPC, but can be oxidized to Cr(VI) prior to determination, is the basis of the speciation analysis. The proposed speciation analysis was sensitive, yet simple, laboreffective, and cost-effective. It has been preliminarily applied for the speciation of Cr(VI) and Cr(III) in spiked river and tap water samples. It can also be used for other automatic liquid-liquid extraction-spectrophotometric determinations.

show abstract

Section: Introductionmentioning

confidence: 99%

Automation of Liquid–Liquid Extraction–Spectrophotometry Using Prolonged Pseudo-Liquid Drops and Handheld CCD for Speciation of Cr(VI) and Cr(III) in Water Samples

et al. 2005

View full text Add to dashboard Cite

show abstract

“…2,7,216,217 Derivatization types of every kind have been utilized for detection of important environmental analytes. Given the variety of types of analytes, which fall under this category, and the multitude of techniques employed to analytically assess components, it is not reasonable to expect a common approach to derivatization methods.…”

Section: Environmentalmentioning

confidence: 99%

Analytical Derivatization Techniques ☆

Parkinson¹

2014

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering

View full text Add to dashboard Cite

For the last 40 years or so, analytical chemists have borrowed well-known reaction techniques from organic and organometallic fields to perform derivatization reactions so as to enhance detection of the elusive analytes they seek. The derivatization mantra has been that, for the technique to be worthwhile, it should be simple to perform, fast (usually less than 15 min), selective, and that the derivatizing reagent should react quantitatively with the analyte and only give one final product. So where are we now? Some derivatization reactions are indeed fast and some are not; some are very selective and some are more universal. However, with a certain care and careful control of optimized conditions, quantitative enhancement outcomes and increased separative power and detection can be very worthwhile. The number of derivatization reagents commercially available itself suggests that there must be some merit to derivatization, that overcomes the associated extra costs: in time (to incorporate the extra reaction step), and in the expense of acquiring, handling, and storing derivatizing reagents. This chapter attempts to show that with proper consideration, it has been feasible to push a chosen analytical technique to give increased selective detection and signal enhancement by derivatization. In many cases, this has made possible the detection of trace components from difficult matrices in a number of scenarios, including on-site analysis, in quality control/continuous analysis methods, or through some remote-sensing platforms. Further, the incorporation of derivatization in an extraction method can be simple and friendly to automated throughput for multiple sample analysis.The fundamental idea of derivatization is that the basic chemical or physical structure of the analytical moiety is changed through a suitable reaction. For example, by labeling compounds for a specific detection purpose, or by changing a functional group to enhance certain chromatographic characteristics, better detection and separation (respectively) can be achieved via the ensuing instrumental techniques. The type of derivatization is highly dependent upon the analytical method and upon the nature of the compound analyzed. There are a variety of good review articles, technical reports, 1 text chapters, 2 and full texts 3-6 that address in detail many specific applications used in analytical derivatization. There are several extraction methods available that are compatible with derivatization. For many analyses, the choice of the best extraction technique is not clear, as many techniques can extract analytes equally well, based on simplicity, applicability, solvent use, expense, detection limit, precision, and time taken to perform the operation. 7 Derivatization techniques have been incorporated into many sample preparation and extractions schemes, to include, but not limited to, total sample headspace, single-drop microextraction (SDME), 8 solid-phase microextraction (SPME), needle trap device (NTD), purge and trap, solid-phase extraction (SPE)...

show abstract

“…Water samples were collected in duplicates and were acidified to pH 2 with sulfuric acid to eliminate biological activity in the water. Florisil column chromatography was used for fractionation of organochlorine pesticides from the water samples by elution with solvents of increasing polarity (Grob, 1985;Onuska, 1989;Thier et al, 1987;US-EPA 608, 1984). The chromatographic columns were slurry packed with 7 g Florisil and settled by tapping.…”

Section: Selection Of Water Samplesmentioning

confidence: 99%

Fourth Symposium on our Environment

Lee¹

1991

View full text Add to dashboard Cite

Techniques and procedures for preparation of aquatic samples for chromatographic analyses

Cited by 35 publications

References 49 publications

Automation of Liquid–Liquid Extraction–Spectrophotometry Using Prolonged Pseudo-Liquid Drops and Handheld CCD for Speciation of Cr(VI) and Cr(III) in Water Samples

Automation of Liquid–Liquid Extraction–Spectrophotometry Using Prolonged Pseudo-Liquid Drops and Handheld CCD for Speciation of Cr(VI) and Cr(III) in Water Samples

Analytical Derivatization Techniques ☆

Fourth Symposium on our Environment

Contact Info

Product

Resources

About