A key component of the quality of pharmaceutical drugs is the control of
impurities. It is important to identify and quantify levels of impurities that may
be present to provide safe, effective and well-controlled medicines. The measurement
and identification of impurities to today’s standards presents significant
challenges to the analytical chemist.
Small amount of drugs and poisons incorporated into human bodies are hidden among large amounts of biological components, such as proteins, lipids, nucleic acids and membranes. It is not easy to detect only a target compound from such complicated matrices. Before instrumental analysis, extraction procedure is usually essential and very important.
In the past several years, there have been many developments in the materials for lead–acid batteries. Silver in grid alloys for high temperature climates in SLI batteries has increased the silver content of the recycled lead stream. Concern about silver and other contaminants in lead for the active material for VRLA batteries led to the initiation of a study by ALABC at CSIRO. The study evaluated the effects of many different impurities on the hydrogen and oxygen evolution currents in ﬂoat service for ﬂooded and VRLA batteries at different temperatures and potentials. ...
For more than 30 years there has been remarkable growth in the need for
quality water purification by all categories of users – municipal, industrial,
institutional, medical, commercial and residential. The increasingly broad
range of requirements for water quality has motivated the water treatment
industry to refine existing techniques, combine methods and explore new
water purification technologies.
Beneficiation (or concentration) processes are gener-
ally used to upgrade the phosphate content by
removing contaminants and barren material prior to
further processing. A few ores are of sufficiently high
quality to require no further concentration. The natu-
rally occurring impurities contained in phosphate
rock ore depend heavily on the type of deposit (sedi-
mentary or igneous), associated minerals, and the
extent of weathering. Major impurities can include
organic matter, clay and other fines, siliceous material,
carbonates, and iron bearing minerals.
Worldwide per capita consumption of alcoholic beverages in 2005 equaled 6.13 litres of
pure alcohol consumed by every person aged 15 years or older. A large portion of this
consumption – 28.6% or 1.76 litres per person – was homemade and illegally produced
alcohol or, in other words, unrecorded alcohol. The consumption of homemade or illegally
produced alcohol may be associated with an increased risk of harm because of unknown
and potentially dangerous impurities or contaminants in these beverages.
A large variation exists in adult per capita consumption (Figure 1).
Impurities in the purge gas, organic compounds outgassing from the plumbing ahead
of the trap, and solvent vapors in the laboratory account for the majority of
contamination problems. The analytical system must be demonstrated to be free from
contamination under the conditions of the analysis by running laboratory reagent
blanks as described in Section 8.1.3. The use of non-Teflon plastic tubing, non-Teflon
thread sealants, or flow controllers with rubber components in the purge and trap
system should be avoided....