Synthesis and mass spectra of 37Cl6-hexachlorocylopentadiene and derived organochlorine insecticides

Chien, David H. T.; Heys, J. Richard

doi:10.1021/jf00110a047

Cited by 4 publications

(3 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At 100 °C, molecular ions are observed for all compounds except mirex (21), kepone (22), and pentac (23). The molecular ion is the most intense peak for endrin (5), endrin aldehyde (6), -chlordene (10), heptachlor epoxide (13), oxychlordane ( 14), a-and -chlordane (15,16), transnonachlor (17), and endosulfan I and II (18,19). No [ -H]"…”

Section: Resultsmentioning

confidence: 99%

“…To further understand the formation of the ion at m/z 235 and other fragment ions, the spectra of isotopically labeled heptachlor epoxide and irans-nonachlor were measured (see Figures 2 and 3). These compounds were synthesized from 92.9% [37Cl]hexachlorocyclopentadiene (16) yielding structures in which the hexachlorocyclopentadlene moiety contains chlorine-37 while remaining portion of the molecule contains chlorines of normal isotopic distribution.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, other compounds with ten carbon skeletons yield the same series of ions. These are chlordene (8), 1-hydroxychlordene (11), heptachlor (12), eland -chlordane (15,16), trans-nonachlor (17), mirex (21), and Pentac (23). A number of oxygenated ten-carbon compounds also show this ion series at m/z values 16 mass units higher:…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Methane enhanced negative ion mass spectra of hexachlorocyclopentadiene derivatives

Stemmler¹,

Hites²

1985

Anal. Chem.

View full text Add to dashboard Cite

The methane, electron capture, negative ion mass spectra of 24 bridged polycyclic Chlorinated pesticides are presented. The effects of ion source pressure and temperature upon the spectra are discussed. These spectra differ from spectra which have previously appeared in the literature, although they were obtained under similar conditions of pressure and temperature. The spectra presented here consist of molecular ions, [M + H -Ci]-ions and various fragment ions, while the previously reported spectra were dominated by low mass ions such as Ci-and by [M + Ci]-adduct ions. I n order to better understand why similar operating conditions result in different modes of ionizatlon (electron capture vs. adduct ion formation), the spectrum of a-chlordane was examined with different concentrations of chloride ion and varylng amounts of sample molecules present In the ion source. Results of this study indicate that the [M + Ci]-/M-ratio increases with increasing sample concentration and added chloride ion. The spectra reported here should be observed when working wtth the small size samples normally encountered when using capillary column GCMS.The polychlorinated, bicyclic compounds shown in Figure 1 are derivatives of hexachlorocyclopentadiene (1). Many of these compounds were introduced in the 1940s as insecticides.It was later discovered that some of these compounds (or their degradation products) were carcinogenic, and thus, with the exception of the endosulfans (18-20) and Pentac (23), their use has been banned or severely restricted (1). Although their use has been curtailed, these compounds are environmentally persistent and have been found in fish (2) and in sediment (3). The electron impact (4) and positive chemical ionization (5) spectra of these compounds have been reported.The derivatives of hexachlorocyclopentadiene, like many environmental contaminants, contain atoms or functionalities which stabilize a negative charge. Thus, the detection and identification of these compounds should be facilitated by the formation of negative ions. Negative ions may be generated (a) by electron capture (electron capture negative ion mass spectrometry, ECNIMS) using a nonreactive reagent gas such as methane or argon (6) or (b) by ion/molecule reactions (negative chemical ionization mass spectrometry, NCIMS) using a reactive reagent gas (7-9). Advantages of ECNIMS over electron impact and positive chemical ionization include selective ionization in the presence of complex matrices (10) and greater sensitivity (6).Dougherty et al. reported the methane negative ion (MNI) mass spectra of ten of these chlorinated bicyclic insecticides (11). The mass spectra were dominated by [M + C1]-and other adduct ions in the high mass region. At low mass, ions such as C1-, HC12-, and H20Cl-were the most intense peaks in the spectra of six compounds. In our laboratory, using the same reagent gas and similar temperature and pressure conditions, we observed spectra which differed from the spectra reported by Dougherty et al. (11). Our results are i...

show abstract