participitated in poster presentation In UK, the potato industry needs to store large quantities of the potato. The major concern is sprouting, which is the inevitable cause for undesirable quality. Chlorpropham (CIPC) is a main sprout suppressant chemical applied as a hot fog to the stored potatoes. However, some residues of CIPC and possible presence of its main breakdown product 3-chloroaniline (3CA) can be found on the treated potatoes. For human risk assessment, there is a concern over 3CA. Recently, the European Communities Commission required the maximum residue level value of both 3CA and CIPC from 2011. Therefore, a consistent method is required to extract and estimate the residue of Chlorpropham and 3-Chloroaniline in potato samples. Methods for analysing CIPC are well documented but not for 3CA. In previous our work, a simplified method has been developed and validated to extract and analysis both CIPC and 3CA based on soaking overnight extraction coupled to HPLC - UV analysis using methanol as solvent extractant. The results of spiking potato skin showed a high recovery of CIPC (> 95%) but the recovery of its metabolite 3CA was less than 5 %. The reason of poor extraction can be due to the irreversible binding of 3CA with potato skin substrate. Therefore, to reduce that, suggestion was made to use a 50:50 mixture of methanol and 1M H2SO4. Experimental recoveries (n=5) at spiking level of 8 mg/kg were above 60% and 80% at ambient and 50 ºC temperature for 24 hours respectively. In order to optimize the extraction method, the final part of this study was to look at real potato samples taken from UK stores and treated with solid CIPC at two temperatures 450 ºC and 270 ºC at concentration levels 14 and 12 g/tonne respectively. The skin of each of these potatoes was extracted applying three different methanol-extracting solutions for 24 hours (100% methanol at lab temperature, 50% methanol in 1M H2SO4 at lab temperature and 50 ºC). The analysis results reported high residue levels of 3CA using hot temperature of mixture of methanol and sulfuric acid which was 2.5 mg/kg for potatoes treated at 450 ºC but lower than 0.2 mg/kg at 270 ºC. While the residue results of CIPC showed no exceed of the MRL level of CIPC (10 mg/kg).