Phosphorus chromatography

Phosphorus oxychloride content and impurities are determined by gas chromatography analyses. 

Ion chromatography has been successfully applied to the quantitative analysis of ions in many diverse types of industrial and environmental samples. The technique has also been valuable for microelemental analysis, e.g. for the determination of sulphur, chlorine, bromine, phosphorus and iodine as heteroatoms in solid samples. Combustion in a Schoniger oxygen flask (Section 3.31 )is a widely used method of degrading such samples, the products of combustion being absorbed in solution as anionic or cationic forms, and the solution then directly injected into the ion chromatograph. 

Denig [118] has reported that the length and structure of the hydrocarbon chains of AOS may be determined by cleavage of the sulfo groups in presence of excess phosphorus pentoxide and hydrogenation of the hydrocarbons before determining the -alkanes and isoalkanes by pyrolysis gas chromatography. 

EC = electrical conductivity detector ECD = electron capture detector FPD = flame photometric detector GC = gas chromatography HPLC = high performance liquid chromatography NPD = nitrogen phosphorus detector TID = thermionic detector UV = ultraviolet spectroscopy... 

Tewari SN, Harplani SP. 1972. Detection of organo-phosphorus pesticide residues in autopsy tissues by thin layer chromatography. Proc Nat Acad Sci India 42(A) 287-292. 

The alcoholysis and transamination of various aminophosphines have been studied as functions of the basicity of the attacking nucleophile and the substituents on phosphorus. As might be expected the reaction is facilitated by electron-withdrawing groups on phosphorus. The hydrolysis of tris(dimethylamino)phosphine (90) to phosphorous acid has been investigated using thin-layer chromatography and the amides (91) and (92) have been identified as intermediates. 

For multi-analyte and/or multi-matrix methods, it is not possible to validate a method for all combinations of analyte, concentration and type of sample matrix that may be encountered in subsequent use of the method. On the other hand, the standards EN1528 andEN 12393 consist of a range of old multi-residue methods. The working principles of these methods are accepted not only in Europe, but all over the world. Most often these methods are based on extractions with acetone, acetonitrile, ethyl acetate or n-hexane. Subsequent cleanup steps are based on solvent partition steps and size exclusion or adsorption chromatography on Florisil, silica gel or alumina. Each solvent and each cleanup step has been successfully applied to hundreds of pesticides and tested in countless method validation studies. The selectivity and sensitivity of GC combined with electron capture, nitrogen-phosphorus, flame photometric or mass spectrometric detectors for a large number of pesticides are acceptable. 

The current methodology to determine residues of alachlor, acetochlor, propachlor, and butachlor in crops and animal products was developed over the last two decades by researchers at the Monsanto Company. These herbicides degrade rapidly in plants and animals to numerous metabolites that can be hydrolyzed to common aniline moieties. Little to no parent herbicide is found as intact residue in crops and animal products therefore, the residue methodology focuses on the determination of the common moieties that are derived from the parent herbicides and their metabolites. Initially, gas chromatography (GC) with flame ionization detection, nitrogen-phosphorus... 

The methyl ester of bispyribac is cleaned up by silica gel column chromatography. Bispyribac-methyl is determined by gas chromatography with nitrogen-phosphorus detection (NPD). 

For cottonseeds, pyrithiobac-sodium is extracted with acetone-water (4 1, v/v). After filtration, the acetone is removed by evaporation under reduced pressure. The residue is adjusted to pH 1 and extracted with ethyl acetate. The extract is cleaned up by liquid-liquid partitioning and methylated with diazomethane. The methyl ester of pyrithiobac is purified by silica gel column chromatography. Pyrithiobac-methyl is determined by gas chromatography (GC) with nitrogen-phosphorus detection (NPD). 

Plant samples are homogenized with sodium hydrogencarbonate aqueous solution to prevent decomposition of the analytes during homogenization. Imibenconazole and its primary metabolite, imibenconazole-debenzyl, are extracted from plan materials and soil with methanol. After evaporation of methanol from the extracts, the residues are extracted with dichloromethane from the residual aqueous solution. The dichloromethane phase is cleaned up on Florisil and Cig columns. Imibenconazole and imibenconazole-debenzyl are determined by gas chromatography/nitrogen-phosphorus detection (GC/NPD). 

Water samples are directly partitioned with dichloromethane (DCM). The DCM exAact is then rotary evaporated and driven to dryness with a sAeam of niAogen. The dry residue is dissolved in acetone and analyzed by gas chromatography/nitrogen-phosphorus detection (GC-NPD). 

A Multi-residue analytical method (for plants) is used for rice, citrus and tomato. Buprofezin and p-OH-buprofezin (as the acetylated derivative, p-AcO-buprofezin) are analyzed simultaneously using gas chromatography/nitrogen-phosphorus detection (GC/NPD). 

Hewlett-Packard Model 6890 equipped with a nitrogen-phosphorus flame ionization detector Capillary column for gas-liquid chromatography (GLC), DB-1, 0.53-mm i.d. x 15 m, l-pm film thickness (J W Scientific)... 

Residues are extracted with acetone. The extract is rotary evaporated to remove acetone, the concentrated residue is diluted with 5% aqueous sodium chloride, and residues are partitioned into dichloromethane. The extract is then concentrated and purified on a silica gel column. Residues of pyriproxyfen are quantitated by gas chromatography with nitrogen-phosphorus detection (GC/NPD). For citrus, a hexane-acetonitrile solvent partition step is required for oil removal prior to the dichloromethane partition step. 

Gas chromatograph, equipped with a nitrogen-phosphorus detector Glass chromatography column, 19 x 300 mm with Teflon stopcock Glass wool (Pyrex)... 

Liquid Chromatography. - Diasteriomeric phosphonodipeptides have been separated by ion exchange column chromatography.267 H.p.l.c. has been used for the analysis of a variety of biologically active phosphorus compounds, such as aminoacid phosphate esters,26 phosphinothrycin,269 inositol triphosphate,270 fructose diphosphate,271 pyridoxal phosphate,272 and ATP.273... 

GC = gas chromatography GPC = gel permeation chromatography MS = mass spectrometry NPD = nitrogen/phosphorus detection... 

A rich family of 2-alkoxycarbonyl-l,3,2-oxazaphospholidine-2-oxides 179-181 was prepared from the reaction of camphor derived aminoalcohols 177 and 178 with either methoxycarbonyl phosphonic dichloride or ethyl dichlorophosphite followed by the reaction with methyl bromoacetate. The reaction with aminoalcohol 177a afforded the phosphorus epimers 179 and 180, in ratios from 1/1 to 12/1 depending on the iV-substituent which could be separated easily by column chromatography. The reaction with aminoalcohols 178a-c, however, gave a single epimer 181a-c in each case (Scheme 50) [81]. 

---