Handbook of Solvents - George Wypych - ChemTech - Ventech!

1062 George Wypych
method of determination of benzene impurities 64 is similar to two methods described
above. 62,63 Normal-nonane is used as an internal standard. In all three methods the internal
standards must be at least 99% pure component.
A gas chromatograph equipped with a thermal conductivity or a flame ionization detector
and capillary or packed columns is used for direct determination of solvents in
paints. 65 Columns are usually packed with either polyethylene glycol (molecular weight
20,000) or a diisodecyl phthalate as liquid phase on diatomaceous earth (60-80 mesh) used
as a solid support. Low viscosity paints are drawn into a syringe and injected through the injection
port. High viscosity paints are diluted with solvent that does not interfere with the
analysis, usually ethyl ether or dichloromethane. A standardized gas chromatographic
technique 66 is capable of determining the 67 solvents most frequently found in hazardous
wastes. Several detectors are suggested for analysis such as flame ionization, electron capture,
thermal conductivity, photoionization, or mass selective. Each waste mixture may
contain a large number of solvents. Their detection is facilitated by the use of gas
chromatograph interfaced with mass spectrometer. The method is designed to facilitate site
assessment, recycling operations, plant control, and pollution programs.
15.1.21 LABELING
Warnings, first aid measures and operating instructions are standardized for vapor
degreasers. 67 Placards containing this information should be placed close to the degreaser in
an area accessible to employees. The placards should contain the information required by
applicable federal and local laws and regulations. The placard should include name of the
solvent used, and warnings indicating that the vapor is harmful, that breathing the vapor
should be avoided, that the machine should only be used with proper ventilation, that swallowing
and contact with the skin should be avoided, that cutting or welding should not be
performed close to the machine, and that the tank should not be entered unless a proper
procedure is followed. In addition, start-up and operation procedures should be available.
Minimum labeling requirements for several halogenated solvents should also follow a
standard practice. 68 The label should state the company name, its logo and address, emergency
telephone numbers, lot number, the net weight, solvent name, its CAS number,
OSHA PEL and ACGIH TLV values, and quantity. In addition, health and safety information,
precautions, first aid, and handling and storage information should be provided.
15.1.22 ODOR
Strips of rapid qualitative paper are dipped in a standard liquid and in the liquid under the
test. Their odor is compared to establish if the odor of sample is more or less acceptable than
the standard to the purchaser and the manufacturer. 69 In a similar method, papers dipped in a
standard and specimens are allowed to dry at room temperature and tested for residual odor
at specified time intervals.
Odor testing may be performed by a selected group of panelist to either determine the
effect of various additives on the odor or taste of a medium or to determine the odor or taste
sensitivity of a particular group of people. 70 For this purpose, a series of samples is prepared
in concentration scale which increases in geometric increments. At each concentration step
two samples containing the medium alone are given to a panelist. The panelist should determine
which sample is different from the other two samples. The panelist should begin with
the lowest concentration selected to be two or three concentration steps below estimated
threshold. The method description contains information on sample selection and preparation,
result, and precision determination.
A method of evaluation of denatured and undenatured alcohols to assess their acceptability
is used. 71 This method is developed specifically to compare methanol, ethanol,