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SEMI-QUANTITATIVE TEST FOR PARAQUAT IN PLASMA AND URINE Syngenta Crop Protection Basel Switzerland Test developed at Syngenta CTL United Kingdom by Bruce.

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Presentation on theme: "SEMI-QUANTITATIVE TEST FOR PARAQUAT IN PLASMA AND URINE Syngenta Crop Protection Basel Switzerland Test developed at Syngenta CTL United Kingdom by Bruce."— Presentation transcript:

1 SEMI-QUANTITATIVE TEST FOR PARAQUAT IN PLASMA AND URINE Syngenta Crop Protection Basel Switzerland Test developed at Syngenta CTL United Kingdom by Bruce Woollen

2 WHAT SAMPLES ARE AVAILABLE ? Blood plasma is the preferred sample If only blood serum is available this can also be tested with limitations for interpretation of results (see slide 19) Urine samples are useful to confirm that a poisoning case involves paraquat

3 DITHIONITE REDUCTION OF PARAQUAT Sodium dithionite alkali PARAQUAT PARAQUAT RADICAL ION (BLUE) Paraquat is converted to a blue colour by sodium dithionite

4 SUMMARY OF THE TEST PART 1 A pre-screen will detect high concentrations of paraquat in plasma and urine If Part 1 is negative PART 2 A more sensitive blue band test will detect paraquat down to 0.1 µg/mL

5 PLASTIC MICROPIPETTE SYRINGE ADAPTOR 15 ML PLASTIC TUBE CEREX SILICA CARTRIDGE WATER WHAT IS NEEDED FOR THE TEST ? 1M NaOH ( FOR URINE) 5 ML OR 10 ML SYRINGE GLASS TUBES 1.2 ML SYNGENTA TEST KIT 1M

6 10 mL WATER 2 MINS ALLOW TO SETTLE 2 mins MIX Sachet B 1g Na 2 S Sachet A 2g NaHC0 3 PREPARATION OF DITHIONITE REAGENT

7 Video clip preparation of dithionite

8 approx 0.9 mL X 20 drops PLASMA or URINE DITHIONITE REAGENT MIX PART 1 : PRE-SCREEN IN PLASMA OR URINE COMPARE COLOUR

9 The limit of detection for paraquat in plasma and urine is about 2-3 µg/mL µg/mL COLOUR CHART FOR PRE-SCREEN

10 Video clip pre-screen

11 RESULTS OF THE PRE-SCREEN If a blue colour is produced the concentration of paraquat is estimated from the chart and no further testing is done If a very faint blue colour or no blue colour is produced the blue band test is carried out Urine samples require an additional step before the blue band test

12 IF TESTING PLASMA PROCEED TO SLIDE NO 14 PREPARATION OF URINE FOR THE BLUE BAND TEST URINE 5 mL 1M NaOH 0.5 mL + CENTRIFUGE MIX URINE FOR TESTING 10 MINS 3000 RPM URINE ONLY DISCARD PELLET 1M

13 PART 2 : BLUE BAND TEST FOR PARAQUAT IN PLASMA OR URINE ~ 3 mL PLASMA or URINE DITHIONITE REAGENT 2 MINS ~ 1 mL WATER BLUE BAND approx 1 mL COMPARE COLOUR

14 µg/mL COLOUR CHART FOR BLUE BAND INTENSITY Chart is applicable to both plasma and urine

15 Video clip of blue band test

16 Proudfoot curve – predictive line Examples : a) 1 µg/mL at 8h after ingestion survival unlikely b) 0.1µg/mL at 12h after ingestion survival likely INTERPRETATION OF PLASMA PARAQUAT RESULTS a b Proudfoot A T, Stewart M S, Levitt T and Widdop B. Paraquat Poisoning : significance of plasma paraquat concentrations. Lancet 1: a b Plasma paraquat concentration µg/mL Time after ingestion (hours) survival unlikely survival likely

17 From Syngenta paraquat treatment booklet Example : 1 µg/mL at 8h after ingestion approximately 30% chance of survival INTERPRETATION OF PLASMA PARAQUAT RESULTS

18 WARNING ABOUT SERUM Plasma versus serum Paraquat concentrations in plasma and serum are NOT equivalent (serum concentrations are about 3 times lower than plasma concentrations) Proudfoot and Syngenta survival curves are based on plasma concentrations of paraquat

19 No blue Colour Pale blue Light blue Navy blue Dark blue From Schermann data INTERPRETATION OF URINE PARAQUAT RESULTS Schermann,J.M, Houze P, Bismuth C and Bourdon R. Prognostic value of Plasma and urine paraquat concentration. Human Toxicology :

20 LIST OF EQUIPMENT AND SUPPLIERS Paraquat test kit containing sodium bicarbonate and sodium dithionite (Syngenta) Glass tubes 40 x 6mm 1.2mL (NLG Scientific) Cerex silica cartridges 3mL 20mg Cat no ( Crawford Scientific) Micropipettes Mini-Pastette LW4231 (Alpha Laboratories) Syringe adaptor (Argonaut Technologies)


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