Traces, Determination

CHEMILUMINESCENCE REACTIONS IN HETEROGENEOUS SYSTEMS FOR TRACE DETERMINATION OF BIOLOGICALLY... 

The aqueous micellai solutions of some surfactants exhibit the cloud point, or turbidity, phenomenon when the solution is heated or cooled above or below a certain temperature. Then the phase sepai ation into two isotropic liquid phases occurs a concentrated phase containing most of the surfactant and an aqueous phase containing a surfactant concentration close to the critical micellar concentration. The anionic surfactant solutions show this phenomenon in acid media without any temperature modifications. The aim of the present work is to explore the analytical possibilities of acid-induced cloud point extraction in the extraction and preconcentration of polycyclic ai omatic hydrocai bons (PAHs) from water solutions. The combination of extraction, preconcentration and luminescence detection of PAHs in one step under their trace determination in objects mentioned allows to exclude the use of lai ge volumes of expensive, high-purity and toxic organic solvents and replace the known time and solvent consuming procedures by more simple and convenient methods. 

C. Hidalgo, J. V. Sancho and P. Hernandez, Trace determination of triazine herbicides by means of coupled liquid cliromatography and large volume injection . Anal. Chim. Acta33 223-29(1993). 

D. Barcelo and M. C. Hennion (Eds), Trace Determination of Pesticides and their Degradation Products in Water (Teclmiques and Instinmentation in Analytical Chemistry, Vol 19), Elsevier Oxford UK (1997). 

In the fifth subdivision, which becomes important when trace determinations are pushed to the limit of detection, Nb is comparable with Nt. Statistical fluctuations in both counts may therefore lead to (1) the... 

Equation 10-6 is the well-known Poisson distribution,5 which is important in counting whenever the number of counts taken is low enough to make a count of zero fairly probable. The analytical chemist, except occasionally in trace determinations, wrill deal with counts so large that he need not concern himself with the Poisson distribution. 

Equation 10-13 is particularly useful in emphasizing the overriding importance of. the background in trace determinations (8.2). See also Table 10-3. 

We wish to call the reader s attention particularly to the later sections of this chapter, which contain methods based on both absorption and emission that are being applied in the life sciences. Not only are these methods of interest in themselves, especially in connection with trace determinations, but also they promise results of great value in the study of life processes. 

Boleda MR, Galceran MT, Ventura F (2007) Trace determination of cannabinoids and opiates in wastewater and surface waters by ultra-performance liquid chromatography-tandem mass spectrometry. J Chromatogr A 1175 38 8... 

Liquid chromatography/electrochemistry (LCEC) has become recognized as a powerful tool for the trace determination of easily oxidizable and reducible compounds. This is because detection of as little as 0.1 pmol of material is readily accomplished with relatively simple and inexpensive equipment. Initial interest in LCEC was generated by the determination of several aromatic matabolites of tyrosine in the central nervous system. However, the application of LCEC into other areas of biochemistry has begun at a growing pace. A bibliography of LCEC applications is available... 

Most phenolic compounds are readily oxidized at carbon electrodes. The oxidation potentials vary widely depending upon the number of ring hydroxyl groups and their positions on the ring. Many compounds of biomedical and industrial interest are phenolic and LCEC based trace determinations are quite popular. 

Phenolic acids and polyphenols are natural plant constituents which impart flavor and textural components to beverages made from these plants. In order to better understand the role of these easily oxidized compounds in the flavor and stability of beverages, it is necessary to determine them at the low concentrations they occur. LCEC has been shown to be quite effective at these trace determinations... 

Many pharmaceuticals and environmental pollutants are aromatic amines. Like phenols, this class of compound is generally oxidizable at carbon electrodes. LCEC has been used to study the metabolism of aromatic amines of both environmental and pharmaceutical origin lcec has also been used for the trace determination... 

Soxhlet extraction followed by liquid chromatography/photodiode-array detection (LC/PAD) is used for the trace determination of propanil and its major metabolite, 3,4-dichloroaniline, in soil. A 10-g soil sample is extracted with methanol in a Soxhlet system for 8 h. After the extracts have been concentrated to dryness, the residue is dissolved in 500 pL of n-hexane. °... 

Joarmon S, Pin C (2001) Ultra-trace determination of Ra in thermal waters by high sensitivity quadrapole ICP-mass spectrometry following selective extraction and concentration using radium-specific membrane disks. J Anal At Spectrom 16 32-37... 

Thouvenot P, Hubert S, Moulin C, et al. 1993. Americium trace determination in aqueous and solid matrices by time-resolved laser-induced fluorescence. Radiochim Acta 61 15-21. 

Plasma sources were developed for emission spectrometric analysis in the late-1960s. Commercial inductively coupled and d.c. plasma spectrometers were introduced in the mid-1970s. By comparison with AAS, atomic plasma emission spectroscopy (APES) can achieve simultaneous multi-element measurement, while maintaining a wide dynamic measurement range and high sensitivities and selectivities over background elements. As a result of the wide variety of radiation sources, optical atomic emission spectrometry is very suitable for multi-element trace determinations. With several techniques, absolute detection limits are below the ng level. 

Ma Y, Zhou M, Jin X et al (2004) Flow-injection chemiluminescence assay for ultra-trace determination of DNA using rhodamine B-Ce(IV)-DNA ternary system in sulfuric acid media. Anal Chim Acta 501 25-30... 

Samaras VG, Thomaidis NS, Stasinakis AS, Lekkas TD (2011) An analytical method for the simultaneous trace determination of acidic pharmaceuticals and phenolic endocrine disrupting chemicals in wastewater and sewage sludge by gas chromatography-mass spectrometry. Anal Bioanal Chem 399 2549-2561... 

Sablayrolles C, Montrejaud-Vignoles M, Benanou D, Patria L, Treilhou M (2005) Development and validation of methods for the trace determination of phthalate in sludge and vegetables. J Chrom 1072 233-242... 

Marano RS, Levine SP, Harvey TM. 1978. Trace determination of subnanogram amounts of acrylonitrile in complex matrices by gas chromatography with a nitrogen-selective detector. Anal Chem 50 1948-1950. 

Chian et al. [69] point out that the Bellar and Iichtenberg [65] procedure of gas stripping followed by adsorption onto a suitable medium and subsequent thermal desorption onto a gas chromatograph-mass spectrometer is not very successful for trace determinations of volatile polar organic compounds such as the low molecular weight alcohols, ketones, and aldehydes. To achieve their required sensitivity of parts per billion, Chian et al. [69] carried out a simple distillation of several hundred ml of sample to produce a few ml of distillate. This achieved a concentration factor of between 10 and 100. The headspace gas injection-gas chromatographic method was then applied to the concentrate obtained by distillation. 

The POCL reaction has been used for trace determinations of hydrogen peroxide, most commonly in environmental and clinical analysis [26-52], The latter applications often include various enzyme systems [34-52], where a number of substrates can be indirectly determined by measuring the hydrogen peroxide that is produced as a by-product in the enzymatic reaction. 

Asperger A. et al., 2002. Trace determination of priority pesticide in water by means of high-speed online solid-phase extraction-liquid chromatography-tandem mass spectrometry using turbulent-flow chromatography columns for enrichment and a short monolithic column for fast liquid chromatographic separation. J Chromatogr A 960 109. 

Barcelo D,HennionMC (1997) Trace determination of pesticides and their degradation products in water, vol. 19. Elsevier, Amsterdam... 

Miege C, Dugay J, Hennion MC. Optimization, validation and comparison of various extraction techniques for the trace determination of polycyclic aromatic hydrocarbons in sewage sludges by liquid chromatography coupled to diode-array and fluorescence detection. J. Chromatogr. A 2003 995 87-97. 

Analysis and Fate of Surfactants in the Aquatic Environment Sample Preparation for Trace Element Analysis Non-destructive Microanalysis of Cultural Heritage Materials Chromatographic-mass spectrometric food analysis for trace determination of pesticide residues... 

Di Corcia A, Bellioni A, Madbouly MD, et al. 1996. Trace determination of phenols in natural waters. Extraction by a new graphitized carbon black cartridge followed by liquid chromatography and reanalysis after phenol derivatization. J Chromatogr 733 383-393. 

Johnson, J.V. Yost, R.A. Faull, K.F. Tandem MS for the Trace Determination of Tryptolines in Crude Brain Extracts. Anal. Chem. 1984, 56, 1655-1661. 

Gardinali PR, Zhao X. 2002. Trace determination of caffeine in surface water samples by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS). Environ Int 28 521. 

Tauxe-Wuersch A, De Alencastro LP, Grandjean D, Tarradellas J (2006) Trace determination of tamoxifen and 5-fluorouracil in hospital and urban wastewaters. Int J Environ Anal Chem 86 473 85... 

Gobel A, McArdell CS, Suter MJ et al (2004) Trace determination of macrolide and sulfonamide antimicrobials, a human sulfonamide metabolite, and trimethoprim in wastewater using liquid chromatography coupled to electrospray tandem mass spectrometry. Anal Chem 76(16) 4756-4764... 

D. H. Fine, F. Rufeh, D. Lieb and D. P. Rounbehler, Description of the thermal energy analyzer (TEA) for trace determination of volatile and nonvolatile N-nitroso compounds. Analytical Chemistry, 1975,47(7), 1188-1191. 

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