The level of suspended solids in a water sample is determined by pouring a carefully measured volume of water through a preweighed filter with a specified pore size, drying the filter to remove the water, and then weighing the filter again. The weight gain of the filter is a dry weight measure of the particulates present in the water sample expressed in units derived or calculated from the volume of water filtered (typically milligrams per liter). Suspended solids measurements are typically performed using glass fiber filter circles that need additional preparation prior to use. However, GE has developed ready-to-use 934-AH RTU glass fiber filters, which are supplied in a prewashed and preweighed
format and enable considerable time savings in the laboratory. 934-AH RTU filters also provide reproducible results and low background contamination.
What are you testing for?
Solids, including:
total suspended
total dissolved
total volatile
Product
GF/C™
934-AH™
glass fiber filters
Ordering information p. 5
Characteristics and benefits
Conform to requirements of standard methodologies:
GF/C for EN 872 (Fig 2); 934-AH for Standard Method 2540D
High loading capacity enabling filtration of very turbid samples
Retention of very fine particles
Product
934-AH RTU
Ordering information p. 5
Characteristics and benefits
Share same benefits as traditional 934-AH glass fiber filters
Ready-to-use format
Prewashed, preweighed according to 2540D
Each pretreated filter comes in an aluminium pan, with the filter weight clearly noted
Each pan has its own unique barcode
Chemical analysis
Dissolved heavy metals
Chemical analyses are commonly performed using analytic instrumentation. Filtration of water samples prior to analysis is good practice in order to remove unwanted particles from the analysis and to protect delicate instrumentation from potentially damaging compounds. Accurate analysis of heavy metals such as lead or mercury depends on not introducing any interference into the sample from consumables used in the analytical preparation process. Water samples are often high in particulate matter, which can present filtration challenges because the particulates can readily block membrane filters. Traditionally, a glass fiber pre-filter has been used to alleviate this problem. However, filters containing some types of glass fiber can introduce trace metals into the sample. To avoid potential sample contamination, GE offers a syringe filter that incorporates an effective pre-filter composed of polypropylene rather than glass fiber. GD/XP syringe filters
GD/XP syringe filters can be used with samples that require inorganic ion analysis (e.g., trace metal analysis using inductively coupled plasma-mass spectrometry [ICP-MS]).
What are you testing for?
Dissolved
heavy metals
Product
GD/XP syringe filters, 25 mm
(filtration in the lab); Fig 3
Ordering information p. 7
Characteristics and benefits
Pre-filter made of polypropylene for minimization of ion extractables
Integrated prefiltration with a dual-layer prefilter stack and one final 0.45 μm membrane
Easy filtration of hard-to-filter samples
Filtration of larger sample volumes compared to filters without pre-filters
Product
Polydisc GW and
Polycap GW in-line filters
(filtration in the field); Fig 4
Ordering information p. 7
Characteristics and benefits
Integrated prefilter
Easy filtration of hard-to-filter samples
Filtration of larger sample volumes compared to filters without pre-filters
Dissolved ions
Filters for sample preparation prior to ion chromatography testing should feature very low levels of anion leaching.
What are you testing for?
Dissolved ions
Product
Anotop™ IC
syringe filters
Characteristics and benefits
Contain a proprietary alumina-based Anopore™ membrane that exhibits very low levels of anion leaching (e.g., fluoride, sulfide, nitrate, nitrite) during ion chromatography (IC) testing
Pigment-free PP housing to eliminate sample contamination
Flexibility – available in either 10 mm or 25 mm diameter
Certified and guaranteed low levels of anion leaching
Dissolved organic carbons
Organic matter content is usually measured as dissolved organic carbon (DOC), which is an important component of the carbon cycle. DOC is defined as the organic matter that is able to pass through a filter, typically one with a 0.45 μm pore size. Puradisc Aqua syringe filters are specifically designed for filtration of environmental samples prior to DOC analysis.
What are you testing for?
Dissolved
organic carbons
Product
Puradisc Aqua 30
syringe filters
Characteristics and benefits
Contain prewashed membranes (prior to assembly) to reduce organic carbon level and ensure low background
Designed for aqueous samples
Hydrophilic cellulose acetate membrane, 30 mm diameter
Suitable for filtration of both aqueous and organic samples. We offer a range of filters for sample preparation for commonly used analytical techniques in water monitoring such as:
HPLC or UHPLC
Continuous flow analysis
Gas chromatography (GC)
Microbiological analysis
Bacterial count and/or detection
MBS I system and membranes
The MBS I filtration system is designed for laboratories that handle high numbers of samples for microbiological quality control.
Membranes
We provide a wide and versatile range of filtration membranes that deliver high-quality performance consistently. The appropriate membrane filter choice will depend on the methodology being followed. ME and Microplus membranes are sterile and individually packed.
Membrane
material
Cellulose mixed ester
High-flux cellulose nitrate
Nylon (polyamide)
Polycarbonate
Product name
ME
MicroPlus
NL
Nuclepore™
Color
White, black or green
White or black
White
White or black
Pore size
0.2 μm/0.45 μm/
0.6 μm/0.8 μm
0.45 μm
0.2 μm/0.45 μm
0.2 μm/0.4 μm
(and other pore sizes)
Application
examples
Enterococcus, E. coli, Clostridia, Fecal coliforms, Staphyloccus, Pseudomonas aeruginosa, etc
Legionella
Legionella
Filtration considerations
Microorganisms in a water sample are collected using a microfiltration membrane filter. The membrane can then be transferred onto a microbiological culture medium for further identification and/or quantification of Microorganisms.
Membrane filtration methods are commonly used for the detection of microorganisms such as E. coli, Clostridia, fecal coliforms, Legionella, Staphylococci, and Pseudomonas aeruginosa. These methods involve the use of membrane filters and filtration manifolds.
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