Detection phosphorus-specific

B in 60 min flow rate 0.5mL/min detection phosphorus-specific detection according to Vaeth et al. [142] injection volume 50 pL sample 0.1 % tetra poly phosphate solution. 

A phosphorus-specific thermionic detector was also adapted from GLC (See Section III.3.b) for use with small-bore HPLC columns208,307,330,334. Based on an electrically heated rubidium salt bead, it permits detection limits of 0.2-0.5 ng of phosphorus and its response is linear with the amount of phosphorus over several orders of magnitude. This detector yields good results with phosphates which cannot be detected by UV spectrophotometry or by fluorescence measurements. 

Other methods used to characterize and identify DOP involve bioassays with Chlorella to study the biological availability and biouptake of the HMW SRP fraction (4, 6). These bioassays indicate that the algal growth responds similarly to HMW SRP and to PO. A preference for PO 3- was detected, and not all of the reactive HMW fraction was used. Enzymatic assays used by Herbes et al. (13) tentatively identified inositol hexaphosphate as part of the DOP. Using an anion-exchange HPLC system with a phosphorus-specific post-column reactor, Minear and co-workers (15,16) possibly have detected inositol hexaphosphate, DNA, and nucleotide fragments in lake waters. 

Verwej et al. [175] have described a procedure for the determination of PH3-containing insecticides in surface water. In this procedure the insecticide is hydrolysed to methylphosphonic acid, and the acid is concentrated by anion exchange and converted to the dimethyl ester. After clean-up on a microsilica gel column the ester is analysed by gas chromatography using a thermionic phosphorus-specific detector. Detection limit is lnmol L 1. 

The BCD is very sensitive to phthalate esters, for example di(2-ethylhexyl) phthalate which is a common contaminant of blood stored in polyvinyl chloride containers (Fig. 1). The AFID can be made virtually specific for phosphorus-containing compounds, but retains its capability to detect phosphorus even when optimised for nitrogen compounds. The contaminant tri-isobutyl phosphate from filter paper is not apparent when using the FID, but produces the largest peak on the chromatogram with the AFID in the nitrogen mode (Fig. 2). 

Recently, another method for the separation and determination of polyphosphonic acids via anion exchange chromatography was described by Vaeth et al. [84], The objective of this work was to develop a phosphorus-specific detection, because the reaction... 

Fig. 3-104. Separation of polyphosphonic acids upon application of phosphorus-specific detection. - Separator column IonPac AS7 eluent 0.17 mol/L KC1 + 0.0032 mol/L EDTA, pH 5.1 flow rate 0.5 mL/min detection photometry at 410 nm after hydrolysis and derivatization with vana-date/molybdate injection 50 pL, l-hydroxyethane-l,l-diphosphonic acid (HEDP), aminotris-(methylenephosphonic acid) (ATMP), ethylenediamine-tetramethylenephosphonic acid (EDTP), l,l-diphosphonopropane-2,3-dicarboxylic acid (DPD), and 2-phosphonobutane-l,2,4-tricarboxylic add (PBTC) (taken from [84]).

Section 6.2.1 illustrated that with the phosphorus-specific detection of polyphosphates and polyphosphonates, two-step post-column derivatizations are now possible. The analysis of a secondary amine via a two-step derivatization and fluorescence detection is exemplified with a herbicide - the glyphosate [jV-(methylphosphono)-glyci ne]. 

Extraction and Analysis of Alachlor. Soil was slurried with 12 mL of water and extracted twice by stirring with 50 mL of ethyl acetate for 45 minutes. The solvent was decanted after each extraction and concentrated on a steam bath. The extract was rediluted with ethyl acetate and analyzed by GLC with nitrogen-phosphorus specific detection. Residues were separated on a 90-cm x 0.2 mm i.d. glass column packed with 5% Apiezon + 0.125% DEGS maintained isothermally at 190°C. Injector and detector were held at 250°C, and gas flow rates were adjusted as needed to obtain maximum sensitivity and resolution. Residues were quantitated by the method of external standards. 

Clarkin, C.M., Minear, R.A., Kim, S. and Elwood, J.W. (1 992) An HPLC postcolumn reaction system for phosphorus-specific detection in the complete separation of inositol phosphate congeners in aqueous samples. Environmental Science and Technology 26, 199-204. 

Filterable organic phosphorus isolated from several sites in and adjacent to the ENR were analysed by this method, using off-line phosphorus-specific mass spectrometry detection. The organic phosphorus was isolated and concentrated by tangential ultrafiltration and lyophilization to produce concentration factors of —25 and final total organic phosphorus concentrations of —1 mg P/1. Column effluent was collected in 1 ml fractions after ultraviolet detection at 214 nm. The chromatographic fractions, along with a matrix blank and 1 and 10 mg/1... 

Fig. 3.18. Ion-pair chromatography of organic matter isolated from Water Conservation Area 2A in the Florida Everglades. Chromatography conditions as described in Fig. 3.11. Samples were concentrated by ultrafiltration and lyophilization by factors of —25. Injection volume was 20 jjlI. On-line ultraviolet detection indicated by solid line off-line phosphorus-specific detection by inductively coupled plasma mass spectrometry (ICP-MS) indicated by dotted line. Fractions were collected for inductively coupled plasma mass spectrometry detection at 1 min (1 ml) intervals. (AUS = absorbance units.)...

Fig. 3.19. Ion-pair chromatography with phosphorus-specific inductively coupled plasma mass spectrometry detection of organic matter isolated from the Experimental Nutrient Removal (ENR) wetland outflow (dotted line) and Water Conservation Area 2A (solid line). Chromatography conditions and sample preparation as described in Eigs 3.11 and 3.12.

The methods for determination of blood cholinesterases inhibition (AChE and BuChE) do not allow identification of the OP and do not provide reliable evidence for exposure at inhibition levels less than 20%. Moreover, they are less suitable for retrospective detection of exposure due to de novo synthesis of enzymes. A method has been developed which is based on reactivation of phosphylated cholinesterase and carboxylesterase (CaE) by fluoride ions. Treatment of the inhibited enzyme with fluoride ions can inverse the inhibition reaction, yielding a restored enzyme and a phos-phofluoridate which is subsequently isolated and quantified by gas chromatography and phosphorus-specific or mass spectrometric detection (Dll, Pll). Human (and monkey) plasma does not contain CaE but its BuChE concentration is relatively high [70-80 nM (M25, D8)], much higher than the concentration of AChE in blood [ca. 3 nM (H5)]. The plasma of laboratory animals, such as rats and guinea pigs, contains considerable concentrations... 

Application of the phosphorus-specific detection (see Sections 3.8.2 and 8.2.1.2) described by Vaeth et al. [142] allows the use of the AS7 column for the analysis of higher condensed phosphates. A mixture of potassium chloride and EDTA [143] is used as an eluent. The potassium chloride concentration determines retention EDTA is added only for improving peak symmetry. However, postcolumn derivatization with ferric nitrate, as mentioned above, cannot be applied in this case because the Fe(III) ions of the derivatization reagent form... 

Figure 3.199 Polyphosphonic acid analysis utilizing phosphorus-specific detection. Separator column lonPac AS7 eluent 0.17 mol/L KCI -h 3.2 mmol/L EDTA, pH 5.1 flow rate ...

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