Poly quantification

Coimbra, M.A. et al., Quantification of polymeric mannose in wine extracts by FT-IR spectroscopy and OSC-PLSl regression, Carbohydrate Poly., 61, 434, 2005. 

The identification and quantification of potentially cytotoxic carbonyl compounds (e.g. aldehydes such as pentanal, hexanal, traw-2-octenal and 4-hydroxy-/mAW-2-nonenal, and ketones such as propan- and hexan-2-ones) also serves as a useful marker of the oxidative deterioration of PUFAs in isolated biological samples and chemical model systems. One method developed utilizes HPLC coupled with spectrophotometric detection and involves precolumn derivatization of peroxidized PUFA-derived aldehydes and alternative carbonyl compounds with 2,4-DNPH followed by separation of the resulting chromophoric 2,4-dinitrophenylhydrazones on a reversed-phase column and spectrophotometric detection at a wavelength of378 nm. This method has a relatively high level of sensitivity, and has been successfully applied to the analysis of such products in rat hepatocytes and rat liver microsomal suspensions stimulated with carbon tetrachloride or ADP-iron complexes (Poli etui., 1985). 

Plasticiser/oil in rubber is usually determined by solvent extraction (ISO 1407) and FTIR identification [57] TGA can usually provide good quantifications of plasticiser contents. Antidegradants in rubber compounds may be determined by HS-GC-MS for volatile species (e.g. BHT, IPPD), but usually solvent extraction is required, followed by GC-MS, HPLC, UV or DP-MS analysis. Since cross-linked rubbers are insoluble, more complex extraction procedures must be carried out. The determination of antioxidants in rubbers by means of HPLC and TLC has been reviewed [58], The TLC technique for antidegradants in rubbers is described in ASTM D 3156 and ISO 4645.2 (1984). Direct probe EIMS was also used to analyse antioxidants (hindered phenols and aromatic amines) in rubber extracts [59]. ISO 11089 (1997) deals with the determination of /V-phenyl-/9-naphthylamine and poly-2,2,4-trimethyl-1,2-dihydroquinoline (TMDQ) as well as other generic types of antiozonants such as IV-alkyl-AL-phenyl-p-phenylenediamines (e.g. IPPD and 6PPD) and A-aryl-AL-aryl-p-phenylenediamines (e.g. DPPD), by means of HPLC. 

Fontaine, F., Ledent, J., Groeninckx, G. and Reynaers, H Morphology and melting behaviour of semi-crystalline poly(ethylene terephthalate) 3. Quantification of crystal perfection and crystallinity, Polymer, 23,185-191 (1982). 

An aliquot of 30 pL is transferred in 250 pi buffer. The solution is shaken for 24 hours at 25 °C. If precipitation occurs the sample is centrifuged and filtrated. The following procedure is the same as for the solubility from solids described above. The achieved throughput is mainly limited by the gradient time. Pan et al. investigated the effect of filtration on the quantification of solubility. They recommend poly(tetrafluoroethylene) (PTFE) as filter material of choice. In their compound set they found 98% recovery after filtration. 

While this earlier research strongly suggests, in a mostly qualitative fashion, that appendageal and (to some extent) intercellular pathways are important in iontophoresis, this deduction is not quantitative and is based primarily upon measurements recorded at inner or exterior surfaces of the skin. To expand on the earlier investigations, studies were recently conducted to visualize and quantify with LSCM the penetration of (a) calcein and (b) a series of FITC-labeled cationic poly-L-lysines (of molecular weights 4 kDa, 7 kDa, and 26 kDa) along the iontophoretic transport pathways within the skin. In addition, quantification of transported fluorescent material along the penetration pathways (e.g., intercellular vs. follicular) was conducted [37c]. 

The effect of temperature on fluorescence has been studied, as has the effect of salt concentration and water-soluble conjugated polymers. A method for the quantification of ssDNA dsDNA is described, as well as kinetics of mismatch hybridization and the kinetics of collision in short ss-nucleic acids. Fluorescence quenching of Cy-5 labelled oligonucleotides by poly(phenylene ethynylene) particles has been shown to be a more sensitive method than excitation of the Cy-5 fluorophore. An ultrasensitive method for the detection of DNA uses highly fluorescent conjugated nanoparticles, and detection limits below IfM were achieved. DNA transport through a carbon nanotube has also been observed using fluorescence microscopy. " ... 

The presence of oxygenated polyaromatic compounds in the product gas is inqjortant because they can act as dioxin sources. Aside for dibenzofuran, the analysis instrument was not calibrated for quantification of other oxygenated poly aromatic compounds. In the gas from LU-gasifier, dibenzofuran stands for between 0.5 and 1.5 %wt. of the total PAHs, The corresponding value for the V5mamo gasifier is considerably less and in most cases dibenzofuran does not exist in the gas. However to be able to study the effect of different parameters on behaviour of these conq>ounds the ratio between the peak area for oxygenated compound and peak area of the dibenzofuran were calculated. These calculated values are presented in Table 5. 

CE is a predestinate for study of polyelectrolyte counter-ion dissociation in free solution and study of the speed of this dissociation process. Counterion dissociation was studied with sodium poly(styrenesulfonates) of different molecular mass using indirect UV detection for quantification of sodium ions in the sample solution. The separation [39] was performed in an unmodified fused-silica capillary using a 0.005 mol L-1 imidazole buffer at pH 4.5 with potassium chloride as internal standard. In the electrophero-... 

Detection of oligosaccharides (e.g., stachyose, raffinose, sucrose, and fructose) in a soybean extract using invertase hydrolysis of p-o-fructo-fructoside to fructose, and further oxidation of this sugar by hexacyanoferrate (III) ion in the presence of fructose dehydrogenase (FDH). This analysis is based on a coimmobilization of invertase from Candida utilis and FDH from Gluconobacter on poly(vinyl alcohol) (PVA) beads and coulometric quantification of the hexacyanoferrate(II) ions formed. 

The amount of purified poly-A RNA is often so small that quantification by A260 measurements in a standard spectrophotometer is too wasteful. Instead the purified poly-A+ RNA can be coelec-trophoresed with total RNA and subjected to Northern analysis with a probe for an abundant mRNA such as eEF-la or GAPDH. Moreover, the Northern analysis has the added advantage of examining the integrity of the purified poly-A+ RNA. 

The GPC analysis was made on a Shodex GPC-101 liquid chromatograph (Tokyo, Japan) equipped with two Shodex KF-804L polystyrene (PSt) mixed gel columns (300 x 8.0 mm bead size = 7 /an pore size = 20-200 A). Tetrahydrofuran (THF) was used as eluent with a flow rate of 0.8 mL/min (40 °C). Sample detection and quantification were made with a Shodex differential refractometer Rl-101 calibrated with known concentrations of polymer in THF. The column system was calibrated with standard PSts and poly(methyl methacrylate)s. 

Huang et al. described a simple, rapid method for the quantitative monitoring of five sulfonamide antibacterial residues in milk. The analytes were concentrated by SBSE based on poly(vinylimidazole-divinylbenzene) monolithic material as coating, and analyzed by HPLC with diode-array detection. The extraction procedure was very simple. Milk was first diluted with water and then directly subjected to sorptive extraction without a requirement for additional steps to eliminate fats and protein in the samples. Under the optimized experimental conditions, low detection limits (S/N = 3) (where S/N = signal-to-noise ratio) and quantification limits (S/N = 10) were achieved for the target compounds within the range of 1.30-7.90 and 4.29-26.3 p.g/1 from spiked milk, respectively. Good linearities were obtained for the sulfonamides with correlation coefficients (R ) above 0.996. Finally, the proposed method was successfully applied to the determination of sulfonamides in different milk samples. 

For poly-isotopic elements like Pd, ID constitutes a further option for quantification. For ID, an isotope enriched spike is added to the sample, allowing the determination of the analyte content by measuring the isotope ratio of the spiked sample. One of the key features of the method is that the result is unaffected by instrumental signal drifts or analyte losses occurring after ID. Since total or reproducible analyte recovery is often problematic in trace and ultra trace analysis, ID is well suited for this task, especially if extensive sample pretreatment is employed (Heumann 2004). 

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