Acta agriculturae Slovenica, 121/4, 1–11, Ljubljana 2025 doi:10.14720/aas.2025.121.4.21287 Original research article / izvirni znanstveni članek Multiresidual gas chromatography-tandem mass spectrometry method for determination of plant protection product residues in jam and jams market survey Helena BAŠA ČESNIK 1, 2 Received November 25, 2024; accepted October 09, 2025 Delo je prispelo 25. november 2024, sprejeto 9. oktober 2025 1 Agricultural Institute of Slovenia, Hacquetova ulica 17, SI-1000 Ljubljana, Slovenia, PhD. 2 corresponding author e-mail: helena.basa@kis.si Multiresidual gas chromatography-tandem mass spectrom- etry method for determination of plant protection product residues in jam and jams market survey Abstract: A multiresidual method for determination of 40 active substances in jam was introduced and validated. Acetone, petroleum ether and dichloromethane were used for extraction and gas chromatograph coupled with tandem mass spectrom- eter for determination. A survey was conducted to test method in practice. 25 jam samples from stores were analysed. 14 of them contained pesticide residues (56 %). Active substances found in samples were fungicides: azoxystrobin, boscalid, cy- prodinil, fenhexamid, fludioxonil, fluopyram, pyrimethanil, te- buconazole and one was insecticide: lambda-cyhalothrin. Key words: jam, pesticide residues, GC-MS/MS, fungi- cides, insecticides Multirezidualna metoda s plinsko kromatografijo sklopljeno s tandemsko masno spektrometrijo za določanje ostankov fitofarmacevtskih sredstev v marmeladi in tržna raziskava marmelad Izvleček: Vpeljali in validirali smo multirezidualno metodo za določanje 40 aktivnih substanc v marmeladi. Za ekstrakcijo smo uporabljali aceton, petroleter in dikloro- metan, za določitev pa plinski kromatograf sklopljen s tan- demskim masnim spektrometrom. Za testiranje metode v praksi smo izvedli raziskavo. Analizirali smo 25 vzorcev marmelade iz trgovin. 14 vzorcev je vsebovalo ostanke fito- farmacevtskih sredstev (56 %). V vzorcih smo določili fungi- cide: azoksistrobin, boskalid, ciprodinil, fenheksamid, fludio- ksonil, fluopiram, pirimetanil, tebukonazol in en insekticid: lambda-cihalotrin. Ključne besede: marmelada, ostanki pesticidov, GC- MS/MS, fungicidi, insekticidi Acta agriculturae Slovenica, 121/4 – 20252 H. BAŠA ČESNIK 1 INTRODUCTION Fruit is part of healthy daily diet. To produce it in quantities large enough for human population, farmers are using plant protection products (PPPs) during its growth. It was reported (Baša Česnik et al., 2011) that fruit in comparison to vegetables contained more active substances per sample (up to nine). In off-fruit season fruit is often consumed preserved as jam (Reichert et al., 2015, Castillo et al., 2019). Jam is a semi-solid food product, prepared by cooking sugar with fruits pulp, pec- tin, acid and other ingredients to a sensibly consistency (Awulachew, 2021). Preparation of jam includes process- ing steps such as washing and cooking (Li et al., 2021). During fruit processing pesticide residues are often de- graded (Alister et al., 2018, Li et al., 2021, Munir et al., 2024). Nevertheless, processed products also in form of jam still contain pesticide residues (Reichert et al., 2015, Makni et al., 2023, EFSA, 2024). Therefore efficient, sen- sitive and selective analytical methods are required for determination of pesticide residues in jam. Jam is classified as high sugar and low water content commodity (SANTE, 2021). Nowadays extraction proce- dure for jam described in literature is mainly QuEChERS (Quick Easy Cheap Effective Rugged and Safe) method, where acetonitrile is used as solvent (Valera-Tarifa et al., 2020; Li et al., 2021; Makni et al., 2023; Oliveira et al., 2024), but also non-solvent SPME (Solid Phase Micro Extraction) method is described (Castillo et al., 2019). Our laboratory used acetone method in past, to which dichloromethane and petroleum ether was added, so that active substances of a wide range of polarity were extracted (Baša Česnik and Gregorčič, 2003; Baša Česnik et al., 2006). This method was modernized by reducing solvents quantities four times (Baša Česnik, 2025) and using buffering similarly like in QuEChERS method. For determination of active substances in jam: a) gas chromatograph coupled with flame ionization detector (GC-FID) (Castillo et al., 2019), b) gas chromatograph coupled with mass spectrometer (GC-MS) (Castillo et al., 2019, Oliveira et al., 2024), c) liquid chromatograph coupled with tandem mass spectrometer (LC-MS/MS) (Reichert et al., 2015, Valera-Tarifa et al., 2020, Li et al., 2021) and d) liquid chromatograph coupled with time of flight detector (LC-TOF) (Makni et al., 2023) were used. The most efficient, sensitive and selective analyti- cal methods are the ones, where tandem mass spectrom- eters are used. Our laboratory used gas chromatograph coupled with tandem mass spectrometer (GC-MS/MS), which enabled unequivocal identification of substances sought on basis of compounds mass spectra and low lim- its of quantification (LOQs). The aim of this paper is to present validation of GC- MS/MS multiresidual method for determination of 40 ac- tive substances in jam. Active substances were herbicides (eight), insecticides/acaricides (nine) and/or fungicides (23). They are or were authorized for use in Slovenia for at least last 3 years. The analytical method was applied in practice. 25 jam samples sampled in Slovenian stores were analysed. Results were compared with literature. 2 MATERIALS AND METHODS 2.1 MATERIAL 2.1.1 Chemicals The certified pesticide standards were purchased from Dr. Ehrenstorfer (Augsburg, Germany). For ex- traction procedure acetone - p.a. grade, dichlorometh- ane – p.a. grade and petroleum ether – p.a. grade, were purchased from J.T.Baker (Deventer, Netherlands). Also acetone HPLC-grade, which was used for preparation of standards, was purchased from J.T.Baker (Deventer, Netherlands). All other chemicals used were obtained by Sigma-Aldrich (Steinheim, Germany). The water used was MilliQ deionised water. 2.1.2 Preparation of the solutions Stock solutions of individual active substances were prepared in acetone. Concentration of each active sub- stance was 625 mg ml-1. From 40 stock solutions, three mixed solutions of all 40 active substances were prepared with a concentration of 5 mg ml-1, 1 mg ml-1 and 0.1 mg ml-1. 2.1.3 EXTRACTION PROCEDURE To 20 g of sample in the beaker, 30 ml of acetone: di- chloromethane: petroleum ether = 1 (v): 2 (v): 2 (v) and 2 g anhydrous CH3COONa and 0.4 ml 100 % acetic acid was added. The mixture was homogenized for two min- utes with a mixer. 10 g of anhydrous Na2SO4 was added. The mixture was homogenized for two minutes with a mixer again. The whole content was filtered through filter paper black ribbon, which contained 20 g of anhydrous Na2SO4, into a 500 ml Soxhlet flask. Matrix was returned to the same beaker, 30 ml of acetone: dichloromethane: petroleum ether = 1 (v): 2 (v): 2 (v) was added, mixture was homogenized for two minutes with a mixer and af- terwards filtered through the same filter paper as previ- ously. Last step was repeated twice. Then solvent solution in Soxhlet flask was evaporated to approximately 2 ml on Acta agriculturae Slovenica, 121/4 – 2025 3 Multiresidual gas chromatography-tandem mass spectrometry method ... of plant protection product residues in jam and jams market survey Active substance Activity typea MRM transitions (Q1, Q2, Q3)b Dwell (ms) CE (V)c 8-hydroxyquinoline F 145→117.1,145→89,117→90 77.5 10, 40, 10 azoxystrobin F 344→329.1,344→171.9,344→155.8 40 10, 40, 40 benthiavalicarb-isopropyl F 181→180,181→126.9,181→83.1 20.3, 17.6 20, 40, 40 boscalid F 140→112,140→76, 45.7 10, 30 clomazone H 204→107,125→99, 87.2 20, 20 cyflufenamid F 412→118.1,412→89.9,118→90.1,118→63 8.2, 8.6 30, 40, 10, 40 cypermethrin A, I 181→152.1,181→126.9,181→76.9 24.2, 19.7, 19.1, 22.1 30, 40, 40 cyprodinil F 225→223.7,224→208.1, 17.3 20, 20 deltamethrin I 253→171.9,253→93.1,253→77 26.9 10, 20, 40 fenhexamid F 301→176.9,301→97,301→54.8 13.5 10, 10, 40 flonicamid I 174→146,174→126,174→69 77.6 10, 20, 40 fluazifop-p-butyl H 383→282.1,254→146, 8.2 10, 20 fludioxonil F 248→182.1,248→154.1,248→127.1 9.7 10, 20, 30 flufenacet H 151→136.1,151→95.1, 30.2 10, 30 fluopicolide F 347→172,209→182,173→145 14.5 30, 20, 10 fluopyram F 173→145,173→95.1, 15.3 20, 30 flutolanil F 172.8→145,172.8→95,172.8→75 12.6 15, 35, 55 indoxacarb I 264→176,264→147.9,264→112.9 23.7 10, 30, 40 iprovalicarb F 158→98,158→72.1,158→55.1 8.6, 8.1 10, 10, 20 kresoxim-methyl F 206→131.1,206→116.1, 12.7 10, 10 lambda-cyhalothrin I 181→152.1,181→127.1,181→77.1 18.6, 17.6 20, 30, 40 metazachlor H 209→132.1,209→117.1,133→131.7 14 20, 40, 20 metrafenone F 408→393,393→378,379→364 29.9 10, 10, 10 metribuzin H 198→82.1,198→55.1, 29.9 20, 40 myclobutanil F 179→125,179→90,179→63 8.6 10, 40, 40 napropamide H 271→72,128→100.1,128→72.1 17.7 20, 10, 10 penconazole F 248→206.1,248→192.1,248→157.1 12.7 10, 10, 30 pendimethalin H 252→191.1,252→162.1,252→106.1 12.2 10, 10, 40 pirimicarb I 238→166.1,166→96.1, 33.4 10, 10 proquinazid F 288→245,288→217,272→216 13.5 10, 30, 20 prosulfocarb H 251→128.1,162→91.1,162→65 32.5 10, 10, 40 pyraclostrobin F 164→132.1,164→104,132→104 34.1 10, 30, 10 pyrimethanil F 198→183.1,198→118, 63.4 20, 40 pyriproxyfen I 226→186.1,226→77.1, 21.1 10, 40 spiroxamine F 100→72.1,100→58.1, 29.9, 38.9 10, 10 tebuconazole F 250→153,250→125,250→70 10.2 10, 30, 10 tebufenpyrad A 335→319.9,333→318.2,333→276.1 21.3 10, 10, 10 tefluthrin I 177→137,177→127,177→87.1 36.6 20, 20, 40 tetraconazole F 336→218.1,336→164, 24.7 20, 30 trifloxystrobin F 222→162.1,222→130,131→116 11.1 10, 10, 20 Table 1: Active substances sought, their activity type, MRM transitions, dwell time and collision energy a A = acaricide, I = insecticide, F = fungicide, H = herbicide b Q = qualifier ion c CE = collision energy Acta agriculturae Slovenica, 121/4 – 20254 H. BAŠA ČESNIK a rotavapor and dried with nitrogen flow. The dry eluate was dissolved in 2 ml of acetone for HPLC using ultra- sound in order to prepare a sample. Extract was filtered with 0.2 mm pore size filter. The extraction procedure is very similar to the one for vegetables (Baša Česnik and Velikonja Bolta, 2024). The only difference is that samples were buffered similar- ly like in QuEChERS method (Lehotay and Maštovska, 2005). Buffering resulted in larger peak areas for 4-40 % for 90 % of active substances. Also metribuzin and spirox- amine gave 40 % higher recoveries. The same extraction procedure was used for fruit (Baša Česnik, 2025). 2.2 DETERMINATION The samples were analysed using a gas chromato- graph (Agilent Technologies 8890, Shanghai, China) coupled with tandem mass spectrometer (Agilent Tech- nologies 7010B, Santa Clara, USA), equipped with a Ger- stel 20PRE0795 multipurpose sampler (Gerstel, Sursee, Switzerland) and a OV-5MS-SIL Ultra Inert column (Ohio Valley Specialty Company, 30 m, 0.25 mm i.d., 0.25 μm film thickness) with a constant flow of helium at 1.2 ml min-1. The GC oven was programmed as follows: 55 °C for 2 min, from 55 °C to 100 °C at 20 °C min-1, from 100 °C to 280 °C at 4 °C min-1, held at 280 °C for 19.75 min. The temperature of the ion source was 230 °C, the auxiliary temperature was 280 °C and the quadrupoles temperature was 150 °C. For qualitative and quantita- tive determination, the MRM transitions were used pre- sented in Table 1. For each active substance two to four transitions were scanned. For calibration matrix match standards were used. Spectrometric parameters for 29 active substances in modernised fruit method (Baša Česnik, 2025) are the same as for the same active substances in jam. Other active substances have different mass transitions, dwell times and collision energies. For sake of completeness they are all presented in Table 1. 2.3 VALIDATION OF METHODS LOQ and linearity Limit of quantification (LOQ) and linearity were checked using matrix match standards. For LOQs the minimum S/N ratio had to be 10. For linearity two rep- etitions for one concentration level, five to eight concen- tration levels for the calibration curve were analysed. Then F test was used to check linear regression (linearity and range). Uncertainty Organically produced peach jam was bought in store and analysed. It contained no pesticide residues sought. For the determination of precision (ISO, 2019), i.e. re- peatability and reproducibility, the extracts of spiked blank peach jam at LOQ were analysed. Within a period of 10 days, two parallel extracts were prepared and ana- lysed each day. Then the standard deviation of the repeat- ability and the standard deviation of reproducibility were both calculated. The uncertainty of repeatability and the uncertainty of reproducibility were calculated by mul- tiplying the standard deviation of repeatability and the standard deviation of reproducibility by the Student’s t factor, for nine degrees of freedom and a 95 % confidence level (t95;9 = 2.262). Ur = t95; 9 x sr ; UR = t95; 9 x sR In SANTE (2021) it is proposed that the meas- urement uncertainty for PPP residues should be 50  %. Analysts must prove during validation that their meas- urement uncertainty is below or equal to the proposed measurement uncertainty. Accuracy Accuracy was verified by checking the recoveries at LOQ. Average recoveries and RSDs were calculated from analysed extracts used for determination of preci- sion (20 measurements per active substance). According to SANTE (2021) acceptable mean recoveries are those within the range of 70  % to 120  %, with an associated repeatability of RSD ≤ 20  %. According to Alder et al. (2000) acceptable mean recoveries at level > 0.001 mg kg-1 and ≤ 0.01 mg kg-1 are those within the range of 60 % to 120 %, with an associated repeatability RSD ≤ 30 %. The same requirement as set by Alder et al. (2000) is set in SANTE (2020). 2.4 SAMPLING 25 jam samples were collected in Slovenian stores in November 2024. The sampling distribution is presented in Table 2. No sample was labelled as ecologically pro- duced. 2.5 RISK ASSESSMENT Long-term (chronic) and short-term (acute) risk as- sessment for consumer was calculated using Supervised Trial Median Residues (STMRs) and Highest Residues (HRs), respectively. Calculated exposure was compared Acta agriculturae Slovenica, 121/4 – 2025 5 Multiresidual gas chromatography-tandem mass spectrometry method ... of plant protection product residues in jam and jams market survey with Acceptable Daily Intake (ADI) for long-term expo- sure and with Acute Reference Dose (ARfD) for short- term exposure with EFSA PRIMo model Rev. 3.1. Ac- ceptable exposures are the ones < 100 % of ADI and/or < 100 % of ARfD. 3 RESULTS AND DISCUSSION 3.1 COMPARISON OF METHOD TO ALREADY ESTABLISHED ONES Previous methods (Baša Česnik and Gregorčič, 2003; Baša Česnik et al., 2006) for determination of pesticide residues in various matrices in our laboratory, used the same mixture of organic solvents for extraction as present method, but in approximately 4-times larger quantities. With this method extraction step with the separatory funnels was omitted, meaning that the meth- od is physically less demanding and less time consum- ing. With the QuEChERS method, the development of methods for determination of pesticide residues almost stopped, meaning that majority is using acetonitrile as extraction solvent. This method proves opposite – usage of other solvents can be very applicable for the purpose. Selection of GC-MS/MS for scanning of extracts, beside unequivocal identification, means also better sensitivity and selectivity that was achieved with the gas chromato- graph coupled with mass spectrometer (GC-MS) in the past. On the other hand selection of active substances is very different as in the past. Focus on presently author- ised active substances modernized the method to be suitable for nowadays monitoring of pesticide residues. The method is robust and can be used also for vegetables and fruit. Present method enables determination of 40 active substances which is more as modernised method for fruit with 29 active substances (Baša Česnik, 2025) or modernised method for vegetables with 35 active sub- stances (Baša Česnik and Velikonja Bolta, 2024). 3.2 VALIDATION OF METHOD 3.2.1 LOQ and linearity For all 40 substances LOQ was 0.005 mg kg-1. For 27 active substances linearity ranged from 0.005–0.035 mg kg-1, for one active substance it ranged from 0.005– 0.045 mg kg-1 and for 12 active substances it ranged from 0.005–0.05 mg kg-1. R2 ranged from 0.958 to 0.995. Re- sults are presented in Table 3. 3.2.2 Uncertainty Uncertainty of repeatability and uncertainty of re- producibility were calculated at LOQ. Uncertainty of repeatability ranged from 0.0005 to 0.0014 mg kg-1 and/or from 9.9 to 27.8  %. Uncertainty of reproducibility ranged from 0.0012 to 0.0020 mg kg-1 and/or from 23.3 to 40.3 %. All uncertainties were <50 % as required by SANTE (2021). Results are presented in Table 3. 3.2.3 Accuracy Recoveries at LOQ were 90.0 to 103.3 % with RSD 10.5 to 17.2  %. All recoveries are in accordance with all three guidelines (Alder et al., 2000; SANTE, 2020; SANTE, 2021). Results are presented in Table 3. No. of sample Description Produced in 1 strawberry Austria 2 strawberry Serbia 3 strawberry Italy 4 strawberry Slovenia 5 strawberry France 6 strawberry Austria 7 appricot Austria 8 appricot Croatia 9 appricot Slovenia 10 appricot Italy 11 appricot Serbia 12 raspberry Slovenia 13 raspberry Serbia 14 raspberry Austria 15 raspberry Austria 16 blueberry Italy 17 blueberry Slovenia 18 blueberry Serbia 19 peach Italy 20 cherry Italy 21 sour cherry Slovenia 22 mandarin Italy 23 orange Serbia 24 plum Italy 25 plum Serbia Table 2: Jam samples collected from stores in Slovenia in 2024 Acta agriculturae Slovenica, 121/4 – 20256 H. BAŠA ČESNIK Active substance Linearity range (mg kg-1) R2 LOQ (mg kg-1) Recovery (%) RSDa (%) Ur b (mg kg-1) Ur c (%) UR d (mg kg-1) UR e (%) 8-hydroxyquinoline 0.005-0.035 0.958 0.005 99.9 14.4 0.0006 12.3 0.0007 14.5 azoxystrobin 0.005-0.05 0.986 0.005 97.2 14.0 0.0002 4.4 0.0007 14.0 benthiavalicarb-iso- propyl 0.005-0.05 0.995 0.005 100.0 10.8 0.0003 5.4 0.0005 11.0 boscalid 0.005-0.05 0.992 0.005 99.0 12.1 0.0002 4.7 0.0006 12.3 clomazone 0.005-0.035 0.971 0.005 98.1 11.8 0.0003 6.6 0.0006 11.8 cyflufenamid 0.005-0.035 0.984 0.005 96.1 14.5 0.0004 8.5 0.0007 14.2 cypermethrin 0.005-0.05 0.986 0.005 98.4 11.1 0.0003 5.6 0.0006 11.2 cyprodinil 0.005-0.035 0.977 0.005 99.3 12.4 0.0004 7.2 0.0006 12.5 deltamethrin 0.005-0.05 0.988 0.005 97.8 12.0 0.0003 5.4 0.0006 12.0 fenhexamid 0.005-0.05 0.98 0.005 101.7 17.2 0.0004 8.4 0.0009 17.8 flonicamid 0.005-0.035 0.978 0.005 98.6 12.0 0.0003 7.0 0.0006 12.0 fluazifop-p-butyl 0.005-0.035 0.983 0.005 99.5 13.0 0.0004 7.1 0.0007 13.2 fludioxonil 0.005-0.05 0.982 0.005 98.7 15.1 0.0004 7.1 0.0008 15.2 flufenacet 0.005-0.045 0.979 0.005 100.4 14.3 0.0005 9.4 0.0007 14.6 fluopicolide 0.005-0.035 0.980 0.005 97.1 10.9 0.0003 6.4 0.0005 10.7 fluopyram 0.005-0.035 0.984 0.005 99.7 12.1 0.0004 8.1 0.0006 12.2 flutolanil 0.005-0.035 0.984 0.005 99.4 14.8 0.0004 8.3 0.0008 15.0 indoxacarb 0.005-0.05 0.987 0.005 99.8 13.8 0.0004 8.1 0.0007 14.0 iprovalicarb 0.005-0.035 0.976 0.005 100.2 15.4 0.0005 9.1 0.0008 15.7 kresoxim-methyl 0.005-0.035 0.984 0.005 97.3 12.4 0.0004 7.9 0.0006 12.3 lambda-cyhalothrin 0.005-0.035 0.976 0.005 98.0 11.5 0.0003 6.2 0.0006 11.5 metazachlor 0.005-0.035 0.975 0.005 97.9 11.7 0.0004 7.1 0.0006 11.7 metrafenone 0.005-0.035 0.974 0.005 99.1 11.3 0.0003 5.3 0.0006 11.5 metribuzin 0.005-0.035 0.973 0.005 90.0 15.5 0.0005 11.0 0.0007 14.1 myclobutanil 0.005-0.035 0.979 0.005 97.8 12.0 0.0004 7.1 0.0006 11.9 napropamide 0.005-0.035 0.981 0.005 99.0 12.4 0.0004 7.5 0.0006 12.5 penconazole 0.005-0.035 0.980 0.005 99.3 11.4 0.0003 6.8 0.0006 11.5 pendimethalin 0.005-0.035 0.979 0.005 97.3 12.8 0.0005 9.4 0.0006 12.6 pirimicarb 0.005-0.035 0.977 0.005 99.4 12.3 0.0003 6.9 0.0006 12.4 proquinazid 0.005-0.035 0.979 0.005 97.5 11.3 0.0003 6.0 0.0006 11.2 prosulfocarb 0.005-0.035 0.978 0.005 99.5 12.1 0.0003 6.9 0.0006 12.3 pyraclostrobin 0.005-0.05 0.971 0.005 103.3 14.7 0.0003 5.1 0.0008 15.5 pyrimethanil 0.005-0.035 0.975 0.005 98.6 11.6 0.0004 7.3 0.0006 11.6 pyriproxyfen 0.005-0.05 0.994 0.005 98.5 12.6 0.0003 6.5 0.0006 12.6 spiroxamine 0.005-0.035 0.978 0.005 97.9 12.2 0.0004 7.7 0.0006 12.1 Table 3: Validation parameters for jam Acta agriculturae Slovenica, 121/4 – 2025 7 Multiresidual gas chromatography-tandem mass spectrometry method ... of plant protection product residues in jam and jams market survey 3.3 SURVEY OF PESTICIDE RESIDUES IN JAM SAMPLES 14 samples of 25 analysed (56.0 %) contained pes- ticide residues. 11 samples of 25 analysed (44.0 %) were pesticides free. Pesticide residues were found in straw- berry, apricot, raspberry, cherry, sour-cherry and orange jam. Residues content was 0.005 to 0.031 mg kg-1. Blue- berry, peach, mandarin and plum jam contained no ac- tebuconazole 0.005-0.05 0.993 0.005 97.6 11.5 0.0003 5.5 0.0006 11.5 tebufenpyrad 0.005-0.05 0.992 0.005 98.0 10.8 0.0003 6.0 0.0005 10.8 tefluthrin 0.005-0.035 0.977 0.005 99.0 11.7 0.0003 6.9 0.0006 11.8 tetraconazole 0.005-0.035 0.979 0.005 98.6 11.9 0.0004 7.7 0.0006 11.9 trifloxystrobin 0.005-0.035 0.983 0.005 96.0 10.5 0.0003 6.2 0.0005 10.3 a RSD was obtained during recovery analyses b,c Ur = uncertainty of repeatability d,e UR = uncertainty of reproducibility Active substance / No of sample boscalid cyprodinil fenhexamid fludioxonil fluopyram pyrimethanil sample no. 2 0.021 0.007 sample no. 3 0.005 sample no. 4 0.009 0.006 sample no. 6 0.009 0.005 0.005 Active substance / No of sample boscalid fluopyram pyrimethanil sample no. 7 0.010 sample no. 8 0.005 0.009 sample no. 9 0.017 0.008 sample no. 11 0.031 Active substance / No of sample azoxystrobin boscalid cyprodinil fenhexamid fludioxonil pyrimethanil sample no. 12 0.015 0.012 0.006 0.015 0.017 sample no. 13 0.014 0.013 0.011 sample no. 15 0.012 0.005 0.015 Active substance / No of sample fludioxonil lambda-cyhalothrin pyrimethanil tebuconazole Sample no. 20: cherry 0.005 Sample no. 21: sour cherry 0.021 0.018 Sample no. 23: orange 0.006 Table 4: Contents (mg kg-1) of pesticide residues found in strawberry jam Table 7: Contents (mg kg-1) of pesticide residues found in cherry, sour-cherry and orange jam Table 5: Contents (mg kg-1) of pesticide residues found in apricot jam Table 6: Contents (mg kg-1) of pesticide residues found in raspberry jam Acta agriculturae Slovenica, 121/4 – 20258 H. BAŠA ČESNIK tive substances sought. Results are presented in Tables 4-7. The highest number of active substances (six) was found in strawberry and raspberry samples. The highest number of active substances per sample was found in one raspberry jam, which contained five active substances sought. Nine active substances were found in all 25 samples. Eight of them were fungicides: azoxystrobin, boscalid, cyprodinil, fenhexamid, fludioxonil, fluopyram, py- rimethanil, tebuconazole and one was insecticide: lamb- da-cyhalothrin. The most frequently found was boscalid in seven samples. All active substances found are author- ised in EU. In jam like in other processed fruit, no Maximum Residue Levels (MRLs) are set like for fruit. Therefore re- Active substance / No of sample boscalid cyprodinil fenhexamid fludioxonil fluopyram pyrimethanil sample no. 2 0.039 0.012 sample no. 3 0.022 sample no. 4 0.037 0.043 sample no. 6 0.023 0.024 0.011 MRL 6 5 10 4 2 5 Active substance / No of sample boscalid fluopyram pyrimethanil sample no. 7 0.014 sample no. 8 0.026 0.039 sample no. 9 0.176 0.066 sample no. 11 0.107 MRL 5 1.5 10 Active substance / No of sample azoxystrobin boscalid cyprodinil fenhexamid fludioxonil pyrimethanil sample no. 12 0.035 0.028 0.011 0.015 0.017 sample no. 13 0.054 0.044 0.063 sample no. 15 0.039 0.020 0.021 MRL 5 10 3 15 5 15 Active substance / No of sample fludioxonil lambda-cyhalothrin pyrimethanil tebuconazole Sample no. 20: cherry 0.030 MRL (cherry) 5 0.3 1 Sample no. 21: sour cherry 0.163 0.091 Sample no. 23: orange 0.009 MRL (orange) 8 Table 11: Contents (mg kg-1) of pesticide residues calculated in cherry, sour-cherry and orange and MRLs for cherry, sour-cherry and orange Table 9: Contents (mg kg-1) of pesticide residues calculated in apricot and MRLs for apricot Table 8: Contents (mg kg-1) of pesticide residues calculated in strawberry and MRLs for strawberry Table 10: Contents (mg kg-1) of pesticide residues calculated in raspberry and MRLs for raspberry Acta agriculturae Slovenica, 121/4 – 2025 9 Multiresidual gas chromatography-tandem mass spectrometry method ... of plant protection product residues in jam and jams market survey calculation was conducted from residues in jam, using fruit portion in jam and processing factors for the active substances during jam preparation, to calculate residues in fruit. Processing factors for jam are available in EU da- tabase (https://zenodo.org/record/1488653#.YHBgL44z- ZaQ). For fenhexamid and pyrimethanil no processing factors were available, therefore processing factor of 1 was used in calculations. Calculated residue content in fruit was 0.009 to 0.176 mg kg-1. Results of residues in fruit with valid MRLs are presented in Tables 8-11. No active substance had calculated residues in fruit above valid MRLs. Nevertheless, risk assessment was conducted. EFSA PRIMo model, used also during authorisation of plant protection products and active substances in EU and Slovenia, does not have residues in jam included as possible inputs. Therefore risk assess- ment was conducted only with calculated residues for fruit. Calculated STMRs and HRs used as input values are presented in Table 12. ADI, ARfD values along with calculated exposure are presented in Table 13. Theoreti- cal Maximum Daily Intake (TMDI) ranged from 0.003 to 2 % of ADI. International Estimated Short Term Intake (IESTI) ranged from 0.2 to 40 % of ARfD. The highest exposure was observed for lambda-cyhalothrin, the most   raspberry                STMR HR             Azoxystrobin 0.035 0.035               appricot  raspberry  strawberry        STMR HR STMR HR STMR HR     Boscalid 0.107 0.176 0.039 0.054 0.022 0.022       raspberry  strawberry            STMR HR STMR HR         Cyprodinil 0.028 0.044 0.030 0.037           raspberry  strawberry            STMR HR STMR HR         Fenhexamid 0.015 0.015 0.039 0.039           cherry  raspberry  strawberry        STMR HR STMR HR STMR HR     Fludioxonil 0.030 0.030 0.042 0.063 0.034 0.043       appricot  strawberry            STMR HR STMR HR         Fluopyram 0.053 0.066 0.011 0.011           cherry                STMR HR             Lambda-cy- halothrin 0.163 0.163               appricot  orange  raspberry  strawberry    STMR HR STMR HR STMR HR STMR HR Pyrimethanil 0.014 0.014 0.009 0.009 0.019 0.021 0.012 0.012   cherry                STMR HR             Tebuconazole 0.091 0.091             Table 12: STMRs and HRs (mg kg-1) for active substances found in different jams STMR = Supervised Trial Median Residue HR = highest residue Acta agriculturae Slovenica, 121/4 – 202510 H. BAŠA ČESNIK toxic active compound found in jam. Nevertheless short- and long- term exposure were acceptable for consumers. Among active substances sought by our labora- tory, Makni et al. (2023) found azoxystrobin, cyprod- inil, fludioxonil, fluopyram, penconazole, pyrimethanil, tetraconazole and trifloxystrobin in strawberry jam; cyprodinil and fludioxonil in apricot jam; azoxystrobin, boscalid, cyprodinil, fenhexamid, fludioxonil and triflox- ystrobin in raspberry jam; fluopyram and tebuconazole in cherry jam. Contents of active substances ranged from 0.001 to 0.066 mg kg-1 (Makni et al., 2023). Reichert et al. (2015) found among active substances sought by our laboratory: azoxystrobin, boscalid, fenhexamid, kresox- im-methyl, myclobutanil, penconazole, pyrimethanil and tebuconazole in strawberry jam; myclobutanil and tebuconazole in apricot jam; tebuconazole in peach jam. Contents ranged from 0.01 to 0.033 mg kg-1 (Reichert et al., 2015). All active substances found by our laboratory, except lambda-cyhalothrin, were found by Reichert et al. (2015) and/or Makni et al. (2023). The reason is probably that these authors did not analyse lambda-cyhalothrin in their samples. The highest concentration determined by Makni et al. (2023) is approximately twice higher as maximum content found by our laboratory. On contrary the highest content found by Reichert et al. (2015) is ap- proximately as high as the one found by our laboratory. 4 CONCLUSIONS Multiresidual method for determination of pesticide residues in jam was introduced and validated on blank peach matrix. The method is suitable for determination of 40 active substances. The LOQ for all active substances was 0.005 mg kg-1. Calibration curves gave linear respons- es with R2 0.958 to 0.995. Recoveries ranged from 90.0 to 103.3 % with RSD 10.5–17.2 % at LOQ. Uncertainties of repeatability ranged from 9.9 to 27.8 % and uncertainties of reproducibility ranged from 23.3 to 40.3  % at LOQ. The method is in accordance with valid guidelines (Alder et al., 2000; SANTE, 2020; SANTE, 2021). 25 jam samples from Slovenian stores were analyzed with this method. Nine active substances were found in jam: azoxystrobin, boscalid, cyprodinil, fenhexamid, flu- dioxonil, fluopyram, lambda-cyhalothrin, pyrimethanil and tebuconazole. Their content range was 0.005 to 0.031 mg kg-1. 5 ACKNOWLEDGEMENTS The author expresses thanks to Janja Debevc for her help with the preparation of the extracts. For financial support the author expresses thanks to Slovenian Re- search Agency (research core funding No. P4-0133). The author declares that all original research data are contained in the article. 6 REFERENCES Alder, L., Hill, A., Holland, P.T., Lantos, J., Lee, S.M., MacNeil, J.D., O'Rangers, J., van Zoonen, P., Ambrus, A. (2000). 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