USGS Science⌕ Search

Geology topics

L.C. Friedman

Publications and source records attributed to L.C. Friedman.

7 recordsLinked to original sources
USGS1985

Validation of an automated fluorescein method for determining bromide in water

Surface, atmospheric precipitation and deionized water samples were spiked with ??g l-1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0.015 to 0.5 mg l-1 of bromide. The correlation coefficient for the same sets of paired data is 0.9987. Recovery data, except for the surface water samples to which 0.005 mg l-1 of bromide was added, range from 89 to 112%. There appears to be no loss of bromide from solution in either type of container.Surface, atmospheric precipitation and deionized water samples were spiked with mu g l** minus **1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0. 015 to 0. 5 mg l** minus **1 of bromide. The correlation coefficient for the same sets of paired data is 0. 9987. Recovery data, except for the surface water samples to which 0. 005 mg l** minus **1 of bromide was added, range from 89 to 112%. Refs.

Water Research↗
USGS1984

Pilot study for U.S. Geological Survey Standard Reference Water Samples for pesticides

The U.S. Geological Survey has been preparing and maintaining a library of standard reference water samples for inorganic constituents for 19 years. Recently, a pilot study was conducted to see if the reference-sample program could be expanded to include pesticides and other organic materials. Two samples containing organochlorine and organophosphorus insecticides, and chlorophenoxy acid herbicides were distributed to a number of laboratories in the United States. One of the samples also contained polychlorinated biphenyls. Interlaboratory data obtained from these round robin studies are presented with intralaboratory information on long-term stability.

Journal of Testing and Evaluation↗
USGS1979

1980 water quality laboratory services catalog

The information in this catalog is provided to assist Water Resources Division personnel in the selection of analytical determinations, estimation of cost, calculation of sample volume requirements, identification of the necessary sample treatment, and selection of laboratory precision for samples to be submitted to Central Laboratories. The catalog contains 18 tables. Tables 1-4 are arranged alphabetically by constituent or schedule, and where available, include parameter name, unit of measurement, lab code or schedule code, applicable range and precision of the method, parameter code, method number and name, and a page index. Tables 1 and 2 list inorganic and organic constituents determined in water samples, table 3 provides information on determinations of chemical and physical properties of sediments, and table 4 lists biological determinations. Page references in these first four tables refer to the tables of determinations (tables 5 through 8) or to the tables of calculations (tables 9 through 12). Constituents that are found in more than one category are cross-referenced (e.g. nitrogen, organic is found in the inorganic table and is cross indexed in the organic table). Tables 13 through 16 list sample containers, sample preservations, and sample designations for each determination. Table 17 lists materials (bottles, preservatives, standardized solutions, and so forth) which may be purchased from the Central Laboratories. Table 18 lists agency codes which can be used to indicate the agency collecting or analyzing samples. Although the catalog is being released now, its effective date is September 11, 1979 to September 10, 1980. The early release is for program planning only.

Open-File Report↗