Quantitative analysis phosphate determination

A final requirement for a chemical kinetic method of analysis is that it must be possible to monitor the reaction s progress by following the change in concentration for one of the reactants or products as a function of time. Which species is used is not important thus, in a quantitative analysis the rate can be measured by monitoring the analyte, a reagent reacting with the analyte, or a product. For example, the concentration of phosphate can be determined by monitoring its reaction with Mo(VI) to form 12-molybdophosphoric acid (12-MPA). 

Competitive immunoassays may also be used to determine small chemical substances [10, 11]. An electrochemical immunosensor based on a competitive immunoassay for the small molecule estradiol has recently been reported [11]. A schematic diagram of this immunoassay is depicted in Fig. 5.3. In this system, anti-mouse IgG was physisorbed onto the surface of an SPCE. This was used to bind monoclonal mouse anti-estradiol antibody. The antibody coated SPCE was then exposed to a standard solution of estradiol (E2), followed by a solution of AP-labeled estradiol (AP-E2). The E2 and AP-E2 competed for a limited number of antigen binding sites of the immobilized anti-estradiol antibody. Quantitative analysis was based on differential pulse voltammetry of 1-naphthol, which is produced from the enzymatic hydrolysis of the enzyme substrate 1-naphthyl phosphate by AP-E2. The analytical range of this sensor was between 25 and 500pg ml. 1 of E2. 

The ash of true leather tanned with tannin consists essentially of calcium carbonate with traces of iron and of phosphates. Coloured leathers may contain metals from the mordants used (tin, copper, iron, chromium, aluminium) tin may also be introduced as stannous chloride used for bleaching. Small quantities of silicates (talc, kaolin) may be employed in the treatment of the leather. Finally, other mineral matters (barium, magnesium and lead salts and sodium chloride) may have been added as filling to increase the weight. Complete quantitative analysis of the ash is rarely necessary, but determination of its calcium content is sometimes required, this being made by the ordinary methods. 

Nemutlu et al. [22] determined lomoxicam in pharmaceutical preparations by a liquid chromatographic method. The separation was achieved on a reversed phase (Nucleosil 100-5 Cis 25 cm x 4.6 mm, 5 gm) column kept at room temperature. The flow rate of mobile phase was 1 ml / min. The mobile phase consisted of 0.1 M phosphate buffer (pH 6)-acetonitrile (60 40) and UV detection at 293 nm. The retention times for the drug and the internal standard, metronidazole, were 5.65 and 3.95 min, respectively. Quantitative analysis of the drug in tablets and injections were performed. The method is fast, simple, inexpensive and applicable over a wide range of concentrations with high precision and accuracy. 

The benchmark spectra used to analyze composite /-irradiated DNA spectra are shown in Figs. 1(B) to 1(E). By determining the low-dose yield [G value (pmol/J)] of each radical using dose-response curves, the low-dose composition of the free radical cohort is determined to be G (35 5%), T- (25 5%), C- [C(N3)H ] (25 5%), XN. (15 5%). Scheme 1 presents the structures of the first three radicals. XN. represents a composite spectrum of neutral radicals, which is assumed to originate mostly with the sugar-phosphate backbone (Cl, C3, C5, C3 gpj J. A semi-quantitative analysis indicates that, of the 15% of assumed backbone radicals, about 11% originate with electron loss and about 4% with low-energy electrons (Sec. 3.3). Thus, about 46% of the stabilized radicals at 77 K are electron-loss... 

Tsoupras et al. used 31p nmr to detect the presence of phosphate groups in the 22-adenosinemonophosphoric ester of 2-deoxy-ecdysone and 22-phospho-2-deoxyecdysone (34). Quantitative NMR has been used in several studies. Wayne et al. used 51p nmr for quantitative analysis of organophosphorous pesticides (35). Zon et al. used NW to study chemical and microsomal oxidation of cyclophosphamide ( ), and to determine the half-life of a cyclophosphamide analogue (37). 

Moate et al. and Kupfermann et al. presented analytical methods involving SPE for the extraction of alkyl phosphates from urine. Moate et alf used SPE for sample cleanup followed by azeotrope distillation and then derivatization of the analytes. Determination of the analytes was achieved using GC-FPD. In contrast, Kupfermann et alf purified the derivatized extract of urine samples from a case of OP poisoning on silica SPE columns followed by quantitative analysis by GC-MS. The LODs ranged from 3 to biiginL. ... 

A quantitative analysis of the phosphate separated on the paper was done by Smith s method (42). Lucena-Conde and Prat s reagent (43) was successfully employed for the colorimetric determination of orthophosphate or condensed phosphates eluted from the sheet of paper. 

Various veterinary residues can be found in food, particularly antibacterial agents used as curative or prophylactic treatments in livestock. A concern with the presence of residual levels of these antibacterial drugs in foods is the increase in antimicrobial resistance. CE methods have been applied to the determination of drug residues in fish and chicken muscle. The quantitative analysis of oxolinic acid fish muscle can be achieved using CZE with a basic phosphate buffer (pH 9) after solid-phase extraction. Enroflox-acin and its metabolite ciproflaxin are detectable in chicken muscle using LIE detection after separation by CZE in an acidic phosphate buffer (pH 2.2). Oxolinic acid and flumequine can be simultaneously determined in chicken by using a basic phosphate buffer (pH 8.02) and UV-visible diode array detection. 

Phospholipids are eluted, ignited and colorimetrically determined as phosphate [1, 47, 53, 159, 189] photodensitometric analysis on the layer is also possible [91, 132, 161]. The experimental conditions given in Fig. 151 are recommended for the two-dimensional separation of phospholipids, sulpholipids and glycohpids, prior to their quantitative analysis. Methods are available for determining ganghosides [73, 196] and other sphingolipids [71, 72, 164]. 

The analysis of phosphates and phosphonates is a considerably complex task due to the great variety of possible molecular structures. Phosphorus-containing anionics are nearly always available as mixtures dependent on the kind of synthesis carried out. For analytical separation the total amount of phosphorus in the molecule has to be ascertained. Thus, the organic and inorganic phosphorus is transformed to orthophosphoric acid by oxidation. The fusion of the substance is performed by the addition of 2 ml of concentrated sulfuric acid to — 100 mg of the substance. The black residue is then oxidized by a mixture of nitric acid and perchloric acid. The resulting orthophosphate can be determined at 8000 K by atom emission spectroscopy. The thermally excited phosphorus atoms emit a characteristic line at a wavelength of 178.23 nm. The extensity of the radiation is used for quantitative determination of the phosphorus content. 

Stabilisers are usually determined by a time-consuming extraction from the polymer, followed by an IR or UV spectrophotometric measurement on the extract. Most stabilisers are complex aromatic compounds which exhibit intense UV absorption and therefore should show luminescence in many cases. The fluorescence emission spectra of Irgafos 168 and its phosphate degradation product, recorded in hexane at an excitation wavelength of 270 nm, are not spectrally distinct. However, the fluorescence quantum yield of the phosphate greatly exceeds that of the phosphite and this difference may enable quantitation of the phosphate concentration [150]. The application of emission spectroscopy to additive analysis was illustrated for Nonox Cl (/V./V -di-/i-naphthyl-p-phcnylene-diamine) [149] with fluorescence ex/em peaks at 392/490 nm and phosphorescence ex/em at 382/516 nm. Parker and Barnes [151] have reported the use of fluorescence for the determination of V-phenyl-l-naphthylamine and N-phenyl-2-naphthylamine in extracted vulcanised rubber. While pine tar and other additives in the rubber seriously interfered with the absorption spectrophotometric method this was not the case with the fluoromet-ric method. 

Holzbecker and Ryan [825] determined these elements in seawater by neutron activation analysis after coprecipitation with lead phosphate. Lead phosphate gives no intense activities on irradiation, so it is a suitable matrix for trace metal determinations by neutron activation analysis. Precipitation of lead phosphate also brings down quantitatively the insoluble phosphates of silver (I), cadmium (II), chromium (III), copper (II), manganese (II), thorium (IV), uranium (VI), and zirconium (IV). Detection limits for each of these are given, and thorium and uranium determinations are described in detail. Gamma activity from 204Pb makes a useful internal standard to correct for geometry differences between samples, which for the lowest detection limits are counted close to the detector. 

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