Grade-42
Equivalent to Whatman Grade 42
Particle Retention: 2.5 μm
Product Appearance: Coarse
Filtration Speed: Slow
Ash Content(%): <0.01
Thickness(μm): 200
Basis Weight(g/m2): 100
Wet Burst(psi): 0.7
Availability: In Stock
Filter Paper Grade 42 (2.5 µm)
Description
When analytical accuracy depends on capturing the smallest particles
In quantitative laboratory filtration, the most critical errors often do not come from instrumentation or weighing systems. They originate from particle loss during filtration.
Filter Paper Grade 42 is designed for this scenario: it prioritizes maximum retention of fine particles over filtration speed to ensure gravimetric accuracy in high-precision workflows.
What Filter Paper Grade 42 actually is?
Filter Paper Grade 42 is an ashless quantitative cellulose filter paper manufactured from high-purity cotton linters under controlled production conditions.
From a laboratory classification perspective, it belongs to: ultra-fine retention ashless quantitative filtration media.
It is designed for workflows where:
- maximum fine-particle capture is required
- gravimetric accuracy depends on complete precipitation retention
- filtration speed is secondary to analytical precision
With approximately 2.5 µm nominal retention, Grade 42 represents the finest retention level in standard quantitative cellulose filter paper series.
Real laboratory behavior (why Grade 42 is selected)
In real analytical environments, filter paper performance is evaluated by error elimination under fine particulate conditions.
1. Fine particle breakthrough (negative mass bias)
Ultrafine precipitates such as barium sulfate or calcium carbonate can pass through coarser media, leading to underestimation in gravimetric analysis.
2. Low-retention failure in trace analysis
Even minimal particle loss becomes significant in high-precision chemical quantification workflows.
3. Controlled slow filtration behavior
Reduced flow rate is an expected trade-off for achieving maximum particle retention and analytical accuracy.
Grade 42 is selected because it minimizes particle breakthrough error in the most demanding gravimetric conditions.
Why laboratories choose Grade 42 in practice
Grade 42 is typically adopted when analytical precision becomes the primary requirement.
- Fine precipitate gravimetric analysis: barium sulfate, calcium carbonate, metastannic acid
- High-precision environmental testing: trace suspended solids quantification
- Instrument protection workflows: pre-filtration for ICP / ICP-MS / AAS systems
In these cases, Grade 42 becomes the maximum retention reference standard.
Technical Specifications
| Parameter | Specification |
| Filter Type | Ashless quantitative cellulose filter paper |
| Particle Retention | ~2.5 µm |
| Filtration Speed | Slow |
| Ash Content | ≤ 0.01% |
| Material | High-purity cotton linters cellulose |
| Thickness | ~200 µm |
| Basis Weight | ~100 g/m² |
| Functional Role | High-retention quantitative filtration medium |
Application Scope
- Gravimetric determination of fine inorganic precipitates
- Soil and sediment ultra-fine fraction analysis
- Environmental monitoring of trace suspended solids
- Mineral and chemical purity testing
- Pre-filtration for ICP / ICP-MS / AAS analytical systems
- Food, pharmaceutical, and industrial residue analysis
Selection logic (how laboratories actually decide)
- If particle breakthrough occurs → upgrade to Grade 42 (higher retention)
- If filtration is too slow → switch to Grade 40 or Grade 41
- If ultra-precision gravimetric accuracy is required → Grade 42 becomes baseline standard
Analytical performance considerations
Grade 42 is widely used in workflows where:
- complete retention of fine precipitates is critical
- mass accuracy must be preserved in gravimetric calculations
- low ash residue is required for high-purity analysis
- instrument contamination risk must be minimized
In quantitative chemistry, even minor particle loss can produce measurable analytical deviation, making Grade 42 a method-critical filtration medium.
Equivalent Grade Reference
| Manufacturer | Equivalent Grade |
| Hawach | Grade 42 |
| Whatman | Grade 42 |
| Advantec | No. 5C |
| Munktell | 393 / 00H |
| Ahlstrom | 94 |
| Macherey-Nagel | 640de |
Ordering Information
| Cat# | Description | Equivalent to Whatman | Package(pcs/pk) |
| 22011213 | Grade 42, Slow, 2.5um, 70mm | 1442-070 | 100pcs/pk |
| 22011214 | Grade 42, Slow, 2.5um, 90mm | 1442-090 | 100pcs/pk |
| 22011215 | Grade 42, Slow, 2.5um, 110mm | 1442-110 | 100pcs/pk |
| 22011216 | Grade 42, Slow, 2.5um, 125mm | 1442-125 | 100pcs/pk |
| 22011217 | Grade 42, Slow, 2.5um, 150mm | 1442-150 | 100pcs/pk |
| 22011218 | Grade 42, Slow, 2.5um, 180mm | – | 100pcs/pk |
FAQ
Why is Grade 42 used for fine precipitate analysis?
Because it provides the highest retention efficiency in the quantitative filter paper series, ensuring minimal loss of ultrafine particles during gravimetric measurement.
Why is filtration slower compared to other grades?
Higher retention density naturally reduces flow rate, which is an intentional trade-off to maximize analytical precision.
Can Grade 42 be used for instrument sample preparation?
Yes. It is widely used for removing fine particulates before ICP, ICP-MS, and AAS analysis to prevent instrument contamination.
What error does Grade 42 help eliminate?
It reduces particle breakthrough error, which directly impacts mass accuracy in gravimetric and trace analytical workflows.
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