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Chemistry
Methods and Problems
Results
Discussion
METHODS
1. Source of material: Saltonstall Ridge, East Haven, CT
2.a) Preparation of samples: Six trees of different sizes collected. Dissected by branch. Twigs
removed and saved. Boles cut to one meter lengths. Field weighedall parts of all fresh-cut trees (wet) on hanging balance. Cut 5-10 cm sections of bole from every other log of the four largest trees.
2.b) In the laboratory: bole section cookies measured, bark removed
from cookies, wood remeasured. Bark weighed wet. Wood
weighed wet. Twigs, branches, bark, cookies all dried at 80° C until no more water weight lost (approximately two weeks.)
2.c) Representative parts ground up using power drill and Wiley mill:
Wood- 5/8" bit drilled on cookies. Initial drill dust discarded. Saved clean
dust from 4-5 drillings avoiding edge and pith. Redried at 80° C.
Bark- Cookie bark from four biggest trees separately ground in a Wiley
mill, and redried.
Branches- Representative parts from selected branches separately ground as
& Twigs either twigs or branch wood in mill, and redried.
2.d) Ashing: Small amounts, (one gram and less) of duplicate samples weighed
out in crucibles, also one quad., two apple leaf standards and two
blanks all ashed at 600° C, reweighed.
3. I. C. P.: To run samples through analyzer, ash was digested in 8 ml of 6 N
HNO3 filtered and diluted to 50 mls with distilled de-ionized (DDI)
water. Heated to simmering, (100° C.)
4. Calculations: I. C. P. data used to calculate concentrations of eight elements in
each part of each tree and in the whole tree.
5. Problems:
a) Data Management: Data sheets with wet and dry weights for branches and their
respective twigs not completed consistently in the field. Ditto dry
samples in the lab. We had to extrapolate from those branches and
twigs for which we did have weights, that twigs usually represent
approximately 10% of the total dry weight of the average Ailanthus
branch. We could test this by collecting more branches in the field
and obtaining wet and dry weights for branches and their twigs.
b) Sample Preparation: Grinding once through the Wiley produces a lumpy
heterogeneous product unlike the fine-powdered apple leaf
standard. We weighed out such tiny amounts of sample from the
randomly mixed mill grindings, that some 0.3g bark duplicates
varied a great deal in actual mineral content.
c) I. C. P.: Calibration blank and three calibration standards of 1,10, and 100
mg/L should have been followed by an extra calibration blank or
been timed for a longer rinse cycle or both. Our sample blank
which followed the 100 mg/L calib. blank was greatly influenced
by it in contrast to the blank run among our samples.
d) The 0.3 gram samples of bark still seemed to be too concentrated
for an accurate reading. In addition to finer grinding in another mill, further dilution may be called for.
