140

Additionally,  a  Varian  triple  quadrupole  mass  spectrometer  (Wallnut  Creek,  USA)  was
used.  Gas  chromatographic  separations  were  carried  out  on  a  CP-3800  gas
chromatograph  (Varian,  Wallnut  Creek,  USA)  applying  a  capillary  of  15  m  length  and
0.25  mm  ID  coated  with  a  film  of  0.25  pm  DB5-MS  (5  %  phenyl-methylpolysiloxane,
J&W  Scientific,  Folsom,  USA).  An  injector  temperature  of  275  °C  and  Helium  as
carrier  gas  (flow  2  ml/min)  were  used.  The  temperature  programme  was  as  follows:  100
°C  for  1  min,  then  with  50  °C/min  to  300  °C,  isothermal  for  4  min.  Splitless  injections
(splitless  time  1.5  min)  of  2.5  pi  sample  volume  were  carried  with  a  Pal  autosampler
(CTC  Analytics,  Zwingen,  Switzerland).
The  following  EI-MS/MS  conditions  were  applied:  Electron  energy  70  eV,  filament
current  300  pA,  resolution  of  quadrupole  1  at  0.8  u  and  of  quadrupole  3  at  1.2  u,  Ar  as
collision  gas  at  a  pressure  of  0.12-0.15  Pa  (0.9-1.1  mTorr).  The  selected  ions  to  be
fragmented  as  well  as  further  parameters  are  given  in  Table  44.  The  precursor  ion  m/z
383  [M-C1] +  and  the  product  ion  m/z  276  [M-4C1] +  were  selected  for  the  internal
standard  1  ’Cio-/ra/7.s'-chlordane  (collision  energy  -21  V).

Table  44:  Selected  precursor  and  product  ions  for  the  determination  of  the  total  PCA  content  by  EI-MS/MS
  with  an  ion  trap  and  triple  quadrupole  mass  spectrometer.  Important  instrument  parameters  and
the  masses  for  the  internal  standard  13 Ci 0 -fran.s-chlordane  are  also  given.

Precursor  ion
(m/z)

Product  ion
(m/z)

Ion  trap

Triple  quadrupole

Excitation  amplitude ­
  (V)

Excitation  “storage
level”  (m/z)

Collision  energy
(V)

91  [C 7 H V ] +

53  [C 4 H 5 ] +

2,0

39,9

-16,0

102  [C 5 H 7 C1] +

65  [C 5 H 5 ] +

0,6

44,7

-10,0

102  [C 5 H 7 C1] +

67  [C 5 H 7 ] +

*

*

-18,0

383  [M-ClT

276  [M-4C1] +

0,85

169,0

-21,0

*not  detectable  in  the  ion  trap.

5.6.9  Quantification  of  chlordanes  by  ECNI-LRMS
Gas  chromatographic  separations  were  carried  out  on  an  HP  5890II  gas  chromatograph
(Hewlett  Packard,  Palo  Alto,  USA),  equipped  with  a  Hewlett  Packard  7673  auto
sampler.  A  fused  silica  capillary  was  employed  of  15  m  length  and  0.25  mm  ID  coated