Appendix III. Comprehensive Index of Pesticide Accurate Mass Molecular Weights
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Appendix III. Comprehensive Index of Pesticide Accurate Mass Molecular Weights This index is intended to facilitate the identification of pesticides by mass spectrometry. Empirical formulae are included to assist recognition of characteristic isotope patterns. It contains exact mass, monoisotopic, molecular weight (M+) data for nearly 2,000 pesticides. Element Nominal Mass Accurate Mass H 1 1.007825 Li 7 7.016000 B 11 11.009300 C 12 12.000000 N 14 14.003100 O 16 15.994900 F 19 18.998400 Na 23 22.989800 Mg 24 23.985040 Al 27 26.981538 Si 28 27.976926 P 31 30.973762 S 32 31.972070 Cl 35 34.968853 K 39 38.963707 Ca 40 39.962590 Mn 55 54.938049 Fe 56 55.934942 Cu 63 62.929600 Zn 64 63.929146 As 75 74.921596 Br 79 78.918337 Sn 120 119.902196 I 127 126.904468 Hg 202 201.970640 When using this index, it is worth bearing in mind that several pesticides have significant oxidative and/or reductive metabolites, so it can be worthwhile to examine molecular weights 16 or 32 daltons heavier or lighter than the observed MW (i.e. ± O or O2). Similarly, methyl esters will be 14 daltons heavier for each carboxylic acid functionality in the molecule. For LC/MS applications using atmospheric pressure ionisation techniques, e.g. electrospray ionisation, protonated or deprotonated ions are usually observed: + + - in positive ion mode, the (M+H) (sometimes (M+NH4) etc. also observed) - in negative ion mode, the (M-H)- The m/z values for these ions can be readily obtained by adding or subtracting 1.007825 (H) to/from the listed M+ values. Appendix III - Page 1 Appendix III - Page 2 PESTICIDE EMPIRICAL FORMULA Monoisotopic M+ hydrogen cyanide .................................................................. CHN ................................................................................. 27.0109 ethylene ................................................................................. C2H4 ................................................................................ 28.0313 formaldehyde ........................................................................ CH2O ............................................................................... 30.0106 cyanamide ............................................................................. CH2N2 ............................................................................. 42.0219 ethylene oxide ....................................................................... C2H4O ............................................................................. 44.0262 06+sodium cyanide ............................................................... CNNa ............................................................................... 48.9929 cyanogen ............................................................................... C2N2 ................................................................................ 52.0062 acrylonitrile ........................................................................... C3H3N ............................................................................. 53.0266 1-methylcyclopropene .......................................................... C4H6 ................................................................................ 54.0470 acrolein ................................................................................. C3H4O ............................................................................. 56.0262 allyl alcohol .......................................................................... C3H6O ............................................................................. 58.0419 carbonyl sulfide .................................................................... COS.................................................................................. 59.9670 methyl isothiocyanate ........................................................... C2H3NS ........................................................................... 72.9986 butylamine ............................................................................ C4H11N ........................................................................... 73.0892 ethyl formate ......................................................................... C3H6O2 ........................................................................... 74.0368 carbon disulfide .................................................................... CS2 .................................................................................. 75.9441 fluoroacetamide .................................................................... C2H4FNO ........................................................................ 77.0277 fluoroacetic acid.................................................................... C2H3FO2 ......................................................................... 78.0117 potassium cyanate ................................................................. CKNO .............................................................................. 80.9617 sodium thiocyanate ............................................................... CNNaS ............................................................................. 80.9650 methylene chloride ................................................................ CH2Cl2 ............................................................................ 83.9534 amitrole ................................................................................. C2H4N4 ........................................................................... 84.0437 piperazine.............................................................................. C4H10N2 ......................................................................... 86.0845 glyoxime ............................................................................... C2H4N2O2 ...................................................................... 88.0273 thiosemicarbazide ................................................................. CH5N3S ........................................................................... 91.0205 calcium cyanide .................................................................... C2CaN2 ........................................................................... 91.9688 methyl bromide ..................................................................... CH3Br .............................................................................. 93.9418 monochloroacetic acid .......................................................... C2H3ClO2 ....................................................................... 93.9821 dithioether ............................................................................. C2H6S2 ............................................................................ 93.9911 4-aminopyridine .................................................................... C5H6N2 ........................................................................... 94.0532 furfural .................................................................................. C5H4O2 ........................................................................... 96.0211 gliftor (component) ............................................................... C3H6F2O ......................................................................... 96.0387 potassium thiocyanate ........................................................... CKNS ............................................................................... 96.9389 ethylene dichloride ................................................................ C2H4Cl2 .......................................................................... 97.9690 hymexazol ............................................................................. C4H5NO2 ........................................................................ 99.0320 sodium fluoroacetate ............................................................. C2H2FNaO2 .................................................................... 99.9937 ACC ...................................................................................... C4H7NO2 ...................................................................... 101.0477 metam ................................................................................... C2H5NS2 ....................................................................... 106.9864 cresol..................................................................................... C7H8O ........................................................................... 108.0575 1,3-dichloropropene .............................................................. C3H4Cl2 ........................................................................ 109.9690 fosetyl ................................................................................... C2H7O3P ....................................................................... 110.0133 α-chlorohydrin ...................................................................... C3H7ClO2 ..................................................................... 110.0134 1,2-dichloropropane .............................................................. C3H6Cl2 ........................................................................ 111.9847 gliftor (component) ............................................................... C3H6ClFO ..................................................................... 112.0091 cellocidin / maleic hydrazide ................................................ C4H4N2O2 .................................................................... 112.0273