Tests & methods

The following tests are available:

1080 in water

The method is used for the determination of trace amounts of sodium monofluoroacetate (1080) in water samples. Samples are derivatised by adding N-ethyl-N0-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDAC) followed immediately by 4-(4-chlorophenoxy)aniline (CPA). The reaction mixture is vortexed for 2 minutes then allowed to stand at room temperature 4 hours, filtered, cleaned on a solid phase extraction cartridge to remove excess derivatising agents and analysed by LC-MSMS. The mobile phases are A- 0.1% formic acid in water, B- 100% acetonitrile.
This method is applicable to potable and surface water samples and the method detection limit in water is 0.0001 ppm.

Terry P. Cooney, Peter Varelis and Justin G. Bendall (2016). High-Throughput Quantification of Monofluoroacetate (1080) in Milk as a Response to an Extortion Threat. Journal of Food Protection, Vol. 79, No. 2, 273-281.

1080 in water, soil, and biological materials

The method is used for the determination of trace amounts of sodium monofluoroacetate in water, soil, and biological samples. Aqueous extracts are obtained from tissue, plant material, soil and honey
samples by the following methods. Tissue and plant material samples are dispersed in an alcohol/water mixture, soil samples are mixed with magnesium carbonate and water then shaken before filtering, and honey samples are mixed with water then sonicated. Aqueous extracts are centrifuged and passed through an ion exchange column to extract the 1080. Milk samples or milk made from milk powder are mixed with acetone and passed through an ion exchange column as for tissue samples. 

Blood serum or plasma, and invertebrate samples, after precipitation of the protein, and urine samples, are added directly to 2% sodium chloride solution ready for derivatisation.  

The 1080 in the aqueous extract or water sample is acidified with hydrochloric acid and converted to the dichloroaniline derivative with N,N'-dicyclohexylcarbodiimide and 2,4-dichloroaniline using ethyl acetate as the extraction solvent. The derivative is cleaned on a silica solid phase extraction cartridge to remove excess derivatising agent, eluted with toluene, and quantified by gas chromatography on a BP-5 capillary column with electron capture detection. 

This test is IANZ accredited.

The limit of detection for different samples is given below:

Ozawa H, Tsukioka T 1987. Gas chromatographic determination of sodium monofluoroacetate in water by derivatization with dicyclohexylcarbodiimide. Analytical Chemistry 59: 2914–2917.

Ozawa H, Tsukioka T 1989. Determination of monofluoroacetate in soil and biological samples as the dichloroanilide derivative. Journal of Chromatography 473: 251–259.

1080 in powders, stock solutions and bait materials

A sample of bait is ground, a sub‑sample taken and acidified.  The monofluoroacetic acid is extracted with ethyl acetate, diluted in acetone and derivatised with pentafluorobenzyl bromide at 55°C.  The resulting solution is analysed on a gas chromatograph equipped with an electron capture detector.

Powder and solution samples are analysed by this method from dilute solutions (1000μg/mL) using the same preparation as for 1080 standards.

1080 wash down sump water samples are tested in the same way as for 1080 standard solutions.

This test is IANZ accredited.

The limit of detection for cereal and carrot bait is 0.0002% (0.002mg/g).
The limit of detection for waste sump water is 5μg/mL.

Compound 1080 grain bait assay. Denver Wildlife Research Center Method No. 8B May 1989.

Alpha-chloralose active ingredient in wheat bait

Wheat baits comprising wheat grains coated with alphachloralose, are used as a bird repellent/toxicant.  Samples of bait are extracted with methanol and the filtered extract is assayed by HPLC, using a C8 column and UV detector set at 203nm.

Anthraquinone in carrot bait and formulations

A sample of cereal bait is ground and a sub-sample is weighed into a centrifuge tube. The sample is extracted with methanol or chloroform using a heated ultrasonic bath followed by shaking, then centrifugation. A small aliquot of the combined extracts is filtered and diluted in mobile phase and then analysed by HPLC.

A sample of Avex suspension is diluted with methanol and water ready for analysis by HPLC.

The analysis is carried out on a liquid chromatograph equipped with a C18 column and a UV/VIS detector.

Primus TM, Avery MI, Cummings JL, Johnston JJ 2000. Liquid chromatographic method for the determination of anthraquinone residues in weathered and unweathered formulated rice seed and surface water in rice fields. Journal of Liquid Chromatography and Related Technologies 23: 2399–2411.

Bait hardness

Ten baits are randomly selected from each bait sample and hardness of individual baits is tested using a Kahl motor driven hardness tester.  

Brodifacoum in stock solutions and bait materials

This method is for the assay of brodifacoum content of concentrates, cereal bait, paste bait and wax block bait.

A sample of concentrate (2.5% w/w) is weighed into a volumetric flask and diluted to 100mL with methanol/water/acetic acid.  This solution is then further diluted in the same solvent to achieve a suitable concentration for HPLC analysis.

A sample of cereal bait is ground and a sub-sample is weighed into a centrifuge tube.  The mixture extracted with methanol and 2M sodium hydroxide solution using an ultrasonic bath followed by shaking.  After neutralizing with acetic acid a small aliquot of the combined extracts is filtered and diluted in mobile phase for HPLC analysis.

A sample of wax block bait is ground and a sub-sample is weighed into a centrifuge tube.  Anhydrous sodium sulphate is added and the mixture extracted with methanol using an ultrasonic bath followed by shaking.  A small aliquot of the combined extracts is filtered and diluted in mobile phase for HPLC analysis.

A sample of paste or gel bait is mixed with anhydrous sodium sulphate and the mixture homogenised and extracted with methanol.  A small aliquot of the combined extracts is filtered and diluted in mobile phase for HPLC analysis.

The analysis is carried out on a liquid chromatograph equipped with a C18 column, a fluorescence detector and a post column reagent pump.  Difenacoum is used as an internal standard for improved quantitation.  A post‑column pH switching technique, using 10% ammonia as the post-column reagent, is used to exploit the natural fluorescence of the rodenticide.

This test is IANZ accredited.

Hunter K 1983. Determination of coumarin anticoagulant rodenticide residues in animal tissue by high‑performance liquid chromatography: I. Fluorescence detection using post‑column techniques. Journal of Chromatography 270: 267–276.

ICI Method PPSM 500. The determination of brodifacoum in baits, concentrates and technical material by high performance liquid chromatography. ICI Plant Protection Division, Yalding Kent (1983).

Brodifacoum in animal tissues

A sample of animal tissue (normally liver) is chopped and a sub-sample is mixed with anhydrous sodium sulphate in a beaker followed by extraction with chloroform/acetone/ammonia.  The extracts are evaporated and taken up in chloroform/hexane for SPE clean up on a aminopropyl column.  The analyte is eluted from the column using 0.005M TBAP in methanol, which is evaporated and the sample taken up in a mobile phase of methanol/water/acetic acid, for HPLC analysis.

A sample of invertebrate tissue is chopped and a sub-sample is mixed with anhydrous sodium sulphate in a beaker followed by chloroform/acetone/ammonia.  The contents of the tube are shaken and centrifuged.  The supernatant is decanted and the extraction process repeated twice more.  The combined extracts are evaporated and taken up in chloroform/hexane for SPE clean up on an aminopropyl column.  The analyte is eluted from the column using 0.005M TBAP in methanol, which is evaporated off and the sample taken up in mobile phase for HPLC analysis.

The analysis is carried out on a liquid chromatograph equipped with a C18 column and fluorescence detection.  A post-column pH switching technique is used to exploit the natural fluorescence of this compound and difenacoum is used as an internal standard for improved quantitation. 

This test is IANZ accredited.

The method detection limit in liver tissue is

Jones A 1996. HPLC determination of anticoagulant rodenticide residues in animal livers. Bulletin of Environmental Contamination and Toxicology 56: 8–15.

Primus TM, Eisemann JD, Matschke GH, Ramey C, Johnston JJ 2001. Chlorophacinone residues in rangeland rodents: an assessment of the potential risk of secondary toxicity to scavengers. In: Johnston JJ ed. Pesticides and wildlife. ACS Symposium Series 771, American Chemical Society, Washington, D.C. USDA. Method 114B (modified). Simultaneous determination of diphacinone and chlorophacinone residues in whole body California ground squirrels. Pp. 164–180.

Brodifacoum in serum and plasma

The serum or plasma sample is extracted with acetonitrile which also removes the protein.  Diethyl ether is added to remove water and the sample evaporated on a vacuum evaporator.  The residue taken up in methanol is analysed by HPLC with fluorescence detection. 

The least detectable level is taken as 0.02μg/mL.

Felice LJ, Murphy MJ 1989. The determination of the anticoagulent rodenticide brodifacoum in blood serum by liquid chromatography with fluorescence detection. Journal of Analytical Toxicology 13: 229–231.

Brodifacoum in water

A water sample (500mL of stream water and 50mL of waste sump water) is passed through a C18 solid phase extraction cartridge.  The analyte is eluted with acetone, evaporated, taken up in methanol and injected into an HPLC using post-column pH switching and fluorescence detection.

The method detection limit is

Hunter K 1983. Determination of coumarin anticoagulant rodenticide residues in animal tissue by high-performance liquid chromatography: I. Fluorescence detection using post-column techniques. Journal of Chromatography 270: 267–276.

Bromadiolone in bait materials

This method is for the assay of bromadiolone in concentrates, cereal bait, paste bait and wax block bait.

A sample of concentrate is weighed into a volumetric flask and diluted with methanol/water/acetic acid.  This solution is then further diluted in the same solvent to achieve a suitable concentration for HPLC analysis.

A sample of wax block bait is ground in a mortar and pestle and a sub-sample is weighed into a centrifuge tube.  Anhydrous sodium sulphate and an internal standard are added and the mixture homogenised and extracted with methanol using an ultrasonic bath followed by shaking.  A small aliquot of the combined extracts is filtered and diluted in mobile phase for HPLC analysis.

The analysis is carried out on a liquid chromatograph equipped with a C18 column using fluorescence detection.  Difenacoum is used as an internal standard for improved quantitation.  A post‑column pH switching technique, using 10% ammonia as the post-column reagent, is used to exploit the natural fluorescence of the rodenticide.

Hunter K 1983. Determination of coumarin anticoagulant rodenticide residues in animal tissue by high-performance liquid chromatography: I. Fluorescence detection using post-column techniques. Journal of Chromatography 270: 267–276.

ICI Method PPSM 500. The determination of brodifacoum in baits, concentrates and technical material by high performance liquid chromatography. ICI Plant Protection Division, Yalding Kent (1983).

Rodenticides (see below) in animal tissues

The method determines the concentration of warfarin, coumatetralyl, bromadiolone, flocoumafen and brodifacoum in animal tissues using HPLC with fluorescence detection.  A post-column pH switching technique is used to exploit the natural fluorescence of these compounds.  Difenacoum is used as an internal standard.

A sample of animal tissue (normally liver) is chopped and a 1g sub-sample is mixed with anhydrous sodium sulphate in a beaker and extracted with chloroform/acetone/ammonia.  The extracts are evaporated and taken up in chloroform/hexane for SPE clean up on an aminopropyl column.  The analytes are eluted from the column using 10mL of 0.005M TBAP in methanol. The solvent is evaporated and the sample taken up in a mobile phase of methanol/water/acetic acid, for HPLC analysis.

This test is IANZ accredited.

The method detection limit in liver tissue is

Jones A 1996. HPLC determination of anticoagulant rodenticide residues in animal livers. Bulletin of Environmental Contamination and Toxicology 56: 8–15.

Primus TM, Eisemann JD, Matschke GH, Ramey C, Johnston JJ 2001. Chlorophacinone residues in rangeland rodents: an assessment of the potential risk of secondary toxicity to scavengers. In: Johnston JJ ed. Pesticides and wildlife. ACS Symposium Series 771, American Chemical Society, Washington, D.C. Pp. 164–180.

USDA. Method 114B (modified). Simultaneous determination of diphacinone and chlorophacinone residues in whole body California ground squirrels.

Cholecalciferol in concentrates and bait material

This method is designed for the assay of cholecalciferol resin (71%), oil (37.5%) and baits (0.8%). 

The sample of cholecalciferol resin is shattered with a mortar and pestle, weighed into a volumetric flask, dissolved in toluene and made up to volume. The solution is diluted with hexane/isopropyl alcohol, filtered and analysed by HPLC.

The sample of cholecalciferol oil concentrate is warmed, mixed and weighed into a volumetric flask, toluene added, ultrasonicated, and made up to volume. The solution is diluted with hexane/isopropyl alcohol, filtered and analysed by HPLC.

The sample of cereal bait is ground in a mortar and pestle and extracted with isooctane using sonication.  The extract is diluted with hexane/isopropyl alcohol, filtered and analysed by HPLC.

The sample of aqueous paste or gel bait is weighed and treated with 1N sodium hydroxide solution, diluted and extracted with toluene on a Varian ChemElut liquid/liquid extraction cartridge.  The extract is filtered and diluted with hexane/isopropyl alcohol for analysis by HPLC.

The sample of ground wax-block bait or oily paste bait is weighed into a volumetric flask, toluene added, ultrasonicated, and made up to volume. The solution is diluted with hexane/isopropyl alcohol, filtered and analysed by HPLC.

The HPLC analysis is carried out on an HPLC equipped with a C18 column and a UV detector set at 265nm.  The solvent is 25% methanol in acetonitrile run isocratically at 1mL/min.

Mauldin RE, Johnston JJ, Riekena CA 1999. An improved method for analysis of cholecalciferol-treated baits. Journal of AOAC International 82: 792–798.

Solvay Pharmaceuticals Method BAI 18-2-1. High-performance liquid chromatographic identification and determination of vitamin D content in crystalline material, resins and oils (1992).

Cinnamon content in bait materials

This method has been developed for the assay of the flavour content in concentrates, and cereal bait and carrot bait.

The sample of cereal bait is soaked in methanol, shaken, then allowed to stand overnight.  The bait and solvent are then homogenised with an Ultra-Turrax homogeniser and shaken for 1 hour.  An aliquot of the extract is removed, filtered and diluted for analysis by HPLC.

The sample of cinnamon concentrate is diluted with methanol and analysed by HPLC as above.

Dighe, V.V., A. A. Gursale, et al. (2005). Quantitative determination of eugenol from Cinnamomum tamala nees and eberm. leaf powder and polyherbal formulation using reverse phase liquid chromatography. Chromatographia 61(9): 443-446.

Gursale, A., V. Dighe, et al. (2010). Simultaneous quantitative determination of cinnamaldehyde and methyl eugenol from stem bark of Cinnamomum zeylanicum blume using RP-HPLC. Journal of Chromatographic Science 48(1): 59-62.

Senanayake, U.M., Lee, T.H., and Wills, R.B.H. (1978). Volatile constituents of cinnamon (Cinnamomum zeylanicum) oils. J. Agric. Food Chem. 26: 822-824.

Coumatetralyl in bait materials

The cereal bait is milled and duplicate samples extracted with methanol, centrifuged, made up to volume and analysed by HPLC.

The sample of paste bait is ground in a mortar and pestle with a silicaceous powdering agent and extracted with methanol.  The extract is filtered, diluted as necessary and analysed on the HPLC as above.

The analysis is carried out on a liquid chromatograph equipped with a C18 column and a UV/VIS detector.

Hunter K 1983. Determination of coumarin anticoagulant rodenticide residues in animal tissue by high-performance liquid chromatography: I. Fluorescence detection using post-column techniques. Journal of Chromatography 270: 267–276.

Houglum JH, Larson RD, Neal RM 1989. High-performance liquid chromatographic separation of indandione rodenticides. Journal of Chromatography 481: 458–460.

Cyanide in bait materials

Feratox tablets (~120mg) are extracted in dilute sodium hydroxide solution and a filtered sub-sample derivatised for HPLC fluorescence detection using taurine and 2,3-napthalenecarboxaldehyde. Analysis is conducted using an Agilent 1200 liquid chromatograph equipped with a fluorescence detector and C18 5µm column.

A sample of cyanide paste is weighed into a separating funnel and extracted with sodium hydroxide solution to which has been added a small amount of hexane to help release the cyanide from the petrolatum paste. An aliquot of this extract is analysed as above.

Technical cyanide is prepared via the same dilution protocol as the 10µg/mL standard and analysed as above.

Diphacinone in bait materials

Samples of homogenised cereal bait or whole paste bait are extracted in a heated ultrasonic bath followed by shaking using a solvent mixture of acetonitrile/methanol/phosphoric acid.  The extract is neutralised with triethanolamine buffer, filtered and injected into an HPLC using paired ion chromatography on a C18 column and a fixed wavelength UV detector at 284nm.

Technical diphacinone is dissolved in methanol and diluted to approximately 2μg/mL in mobile phase and analysed by HPLC.

Hunter K 1984. Reversed phase ion-pair liquid chromatographic determination of chlorophacinone residues in animal tissues. Journal of Chromatography 299: 405–414.

Diphacinone in animal tissues

The method determines the levels of diphacinone in animal and invertebrate tissues using paired ion chromatography (PIC) and a UV detector at 284nm.

A sample of animal tissue (normally liver) is weighed into a glass Oak Ridge tube, chlorophacinone added as an internal standard and anhydrous sodium sulphate added and extracted with chloroform/acetone/formic acid.  The extracts are evaporated and taken up in hexane/chloroform for clean up on a carbograph SPE column followed by an aminopropyl column.  The eluent is evaporated to dryness and taken up in mobile phase for quantification by HPLC analysis, using a C18 column and UV detector set at 284nm.

A sample of invertebrates (normally whole chopped insect/s) is weighed into a glass oak ridge tube. Chlorophacinone, to act as an internal standard and anhydrous sodium sulphate are added and extracted with chloroform/acetone/formic acid. The combined extracts are evaporated and taken up in hexane/chloroform for clean up on an aminopropyl SPE column. The analyte is eluted from the SPE column with TBAP in methanol, which is then evaporated to dryness and taken up in mobile phase for quantification by HPLC analysis, using a C18 column and UV detector set at 284nm.

This test is IANZ accredited.

The method detection limit is

Determination of diphacinone residues in snails and slugs. National Wildlife Center, Fort Collins.

Determination of diphacinone and chlorophacinone residues in whole body and liver of pocket gophers. National Wildlife Center, Fort Collins, Method 80A.

Simultaneous determination of diphacinone and chlorophacinone residues in whole body California ground squirrels. National Wildlife Center, Fort Collins, Method 114B.

Moisture content of bait materials

This method has been developed to measure the moisture content and solids content of cereal baits, paste, and gels.

The sample is weighed into a dish and placed in an oven at 100°C for a period of 24 hours. After heating it is re-weighed. The moisture content is calculated using the appropriate spreadsheet.

This test is IANZ accredited.

PAPP in baits

A sample of paste, encapsulated spheres, or active is mixed and a sub sample is weighed into a centrifuge tube. Methanol is added, the tube shaken for 10 minutes, centrifuged and decanted into a conical flask. The extraction is repeated twice more, made up to volume, and a sub-sample filtered for HPLC analysis using a C18 column and a UV detector set at 300nm. The mobile phase is methanol/water buffered with ammonium acetate, acetic acid and triethanolamine.

This test if IANZ accredited

PAPP in water

A 200mL water sample is passed through a C18 solid phase extraction cartridge.  The analyte is eluted with methanol, evaporated, taken up in mobile phase and a sub-sample filtered and diluted for HPLC analysis using a C18 column and a UV/Vis detector set to 300nm.  The mobile phase is methanol/water buffered with ammonium acetate, acetic acid and triethanolamine.

The method detection limit is

PAPP in tissues

A sample of tissue is chopped, mixed and a 2g sub sample weighed into a beaker with anhydrous sodium sulphate. The mixture is extracted three times with buffered methanol and evaporated to dryness. The extract is dissolved in mobile phase and analysed using a C18 column and UV detection. The detection limit is set at 1ppm for both liver and muscle tissue.

Pindone in bait materials and formulations

Duplicate samples of homogenised bait are extracted on a shaking machine with a solvent mixture of acetonitrile/methanol/phosphoric acid, then neutralised with triethanolamine buffer, and filtered.

Technical Pival or Pivalyn (the sodium salt) is dissolved in methanol or water as appropriate and diluted in mobile phase.  Samples are analysed by HPLC using paired ion chromatography on a C18 column, with a UV detector at 284nm.

This test is IANZ accredited.

Hunter K 1984. Reversed phase ion-pair liquid chromatographic determination of chlorophacinone residues in animal tissues. Journal of Chromatography 299: 405–414.

Pindone in animal tissues

The method determines the levels of pindone in animal and invertebrate tissues using paired ion chromatography (PIC) and a UV detector at 284nm.

A sample of animal tissue (normally liver) is weighed into a glass Oak Ridge tube, chlorophacinone added as an internal standard and anhydrous sodium sulphate added and extracted with chloroform/acetone/formic acid.  The extracts are evaporated and taken up in hexane/chloroform for clean up on a carbograph SPE column followed by an aminopropyl column.  The eluent is evaporated to dryness and taken up in mobile phase for quantification by HPLC analysis, using a C18 column and UV detector set at 284nm.

A sample of invertebrates (normally whole chopped insect/s) is weighed into a glass oak ridge tube. Chlorophacinone, to act as an internal standard and anhydrous sodium sulphate are added and extracted with chloroform/acetone/formic acid. The combined extracts are evaporated and taken up in hexane/chloroform for clean up on an aminopropyl SPE column. The analyte is eluted from the SPE column with TBAP in methanol, which is then evaporated to dryness and taken up in mobile phase for quantification by HPLC analysis, using a C18 column and UV detector set at 284nm.

The method detection limit is

Hunter K 1984. Reversed phase ion-pair liquid chromatographic determination of chlorophacinone residues in animal tissues. Journal of Chromatography 299: 405–414.

Method 80A, 24.11.97. Determination of diphacinone and chlorophacinone residues in whole body and liver of pocket gophers. National Wildlife Center, Fort Collins.

Pindone in soil

A sample of sieved soil is extracted on a shaking machine with a solvent mixture of acetonitrile/methanol/phosphoric acid, neutralised with triethanolamine buffer, filtered and injected into an HPLC using paired ion chromatography on a C18 column and a UV detector at 284nm.

The limit of detection in soil is 0.5μg/g.

Hunter K 1984. Reversed phase ion-pair liquid chromatographic determination of chlorophacinone residues in animal tissues. Journal of Chromatography 299: 405–414.

Pindone and diphacinone in water

A water sample (100mL of stream water or 10mL waste sump water) is passed through a C18 solid phase extraction cartridge.  The analyte is eluted with 0.005M tetrabutyl ammonium phosphate in methanol, evaporated, taken up in mobile phase and injected into an HPLC using a C8 column and UV detector set at 284nm. Chlorphacinone is added to the sample to act as internal standard.

The method detection limit is

Hunter K 1983. Determination of coumarin anticoagulant rodenticide residues in animal tissue by high-performance liquid chromatography: I. Fluorescence detection using post-column techniques. Journal of Chromatography 270: 267–276.

Rotenone in water

The rotenone content is measured on 500mL water samples stabilised with phosphoric acid received in amber glass bottles.  The sample is passed through a C18 solid phase extraction cartridge.  The analyte is eluted with 5mL methanol, filtered and tested by HPLC using a 5µm C18 column, UV detector set at 295nm and methanol/water (90/10) at 0.8mL/min.

The method detection limit is

* May depend on the presence of interfering peaks.

Warfarin in bait materials

The cereal bait is milled and samples extracted with a solvent mixture of methanol/water/acetic acid, centrifuged, made up to volume and injected into an HPLC with post‑column pH change and fluorescence detection.

The sample of paste bait is ground in a mortar and pestle with a silicaceous powdering agent and extracted with a solvent mixture of methanol/water/acetic acid.  The extract is filtered and analysed on the HPLC as above.

Steyn JM, Van der Merwe HM, de Kock MJ 1986. Reversed-phase high-performance chromatographic method for the determination of warfarin from biological fluids in the low nanogram range. Journal of Chromatography 378: 254–260.

Hunter K 1983. Determination of coumarin anticoagulant rodenticide residues in animal tissue by high-performance liquid chromatography: I. Fluorescence detection using post-column techniques. Journal of Chromatography 270: 267–276.

Houglum JH, LarsonRD, Neal RM 1989. High-performance liquid chromatographic separation of indandione rodenticides. Journal of Chromatography 481: 458–460.

Warfarin in serum/plasma

The method determines the levels of warfarin in serum and plasma using fluorescence detection.  A post-column pH switching technique using a mixture of ammonia, methanol and water exploits the natural fluorescence of this compound. Coumatetralyl is used as an internal standard.

The serum or plasma sample is extracted in diethyl ether in the presence of hydrochloric acid. The extract is then dried down on a heating block fitted with an air blow down system.  The residue is taken up in mobile phase is analysed by HPLC with fluorescence detection.

The method detection limit is

Steyn JM, Van Der Merwe HM 1986. Reversed-phase high performance liquid chromatographic method for the determination of warfarin from biological fluids in the low nanogram range. Journal of Chromatography 378: 254–260.

K Hunter 1983. Determination of coumarin anticoagulant rodenticides residues in animal tissue by high-performance liquid chromatography: Fluorescence detection using post-column techniques. Journal of Chromatography 270: 267–276.

Zinc phosphide in bait materials

This method has been developed to assay the zinc phosphide content of cereal and paste bait.

An amount of cereal bait material is ground with a mortar and pestle.  A small aliquot of the homogeneous mix is weighed into a glass centrifuge tube and toluene and 5% sulphuric acid is added.  The tube is shaken and centrifuged.  A GC vial is filled with the toluene mix for analysis using an HP5 column and nitrogen phosphorus detector.

The paste bait is thoroughly mixed and a small aliquot is weighed into a centrifuge tube and analysed in a similar way to the cereal bait.

An amount of granulated micro-encapsulated zinc phosphide (MEZP) is weighed directly into the 35mL centrifuge tube.  The tube is capped and shaken on a horizontal shaker.  A GC vial is filled with the toluene mix for analysis.

Corley J, Kahl J, Burkhart D, Diaz E, Möller G 1998. Rapid zinc phosphide trace analysis in agricultural commodities by phosphine generation, toluene trapping, and gas chromatography. Journal of Agricultural and Food Chemistry 46: 999–1004.

Mauldin RE, Goldade DA, Engeman RM, Goodall MJ, Craver RK, Johnston JJ 1996. Determination of zinc phosphide residues in the California ground squirrel (Spermophilus beecheyi) by gas chromatography – flame photometric detection. Journal of Agricultural and Food Chemistry 44: 189–194.

Zinc phosphide in animal tissues

The zinc phosphide content of stomach samples is measured by this method.  An amount of stomach contents is homogenised using the Ultra-Turrax and a small aliquot of the homogeneous mix is weighed into a centrifuge tube followed by toluene and 5% sulphuric acid.  The tube is capped and shaken on a horizontal shaker.  The tube is then centrifuged and a GC vial filled with the toluene solution for analysis using an HP5 column and nitrogen phosphorus detector.

Corley J, Kahl J, Burkhart D, Diaz E, Möller G 1998. Rapid zinc phosphide trace analysis in agricultural commodities by phosphine generation, toluene trapping, and gas chromatography. Journal of Agricultural and Food Chemistry 46: 999–1004.

Mauldin RE, Goldade DA, Engeman RM, Goodall MJ, Craver RK, Johnston JJ 1996. Determination of zinc phosphide residues in the California ground squirrel (Spermophilus beecheyi) by gas chromatography – flame photometric detection. Journal of Agricultural and Food Chemistry 44: 189–194.

Zinc phosphide in soil

A small homogeneous aliquot of soil is weighed into a centrifuge tube to which toluene and 5% sulphuric acid is added.  The tube is capped and shaken on a horizontal shaker.  The tube is then centrifuged and a GC vial filled with the toluene solution for analysis using an HP5 column and nitrogen phosphorus detector.

Corley J, Kahl J, Burkhart D, Diaz E, Möller G 1998. Rapid zinc phosphide trace analysis in agricultural commodities by phosphine generation, toluene trapping, and gas chromatography. Journal of Agricultural and Food Chemistry 46: 999–1004.