TJ Environmental is a retail business providing quality products and support to environmental laboratories and testing professionals. We offer filters and testing equipment for liquid and areosol monitoring (such as HotBlock, ghost wipes, BOD bottles, TCLP products, metals analysis products, ProWeigh filters, MaxFil, ZHE+, Digestion Vessels, flow meters, acetone vaporizers, and various filters for water and air testing) at very competitive prices.  We currently stock products by BGI, Environmental Express, J.D. Technical Services, Menzel, SPI Supplies and Technovation. Most orders received before 3 pm can be shipped to you from our office the same day that you place your order. That means no uncertain waiting time and delays, as with many suppliers. HotBlocks, BOD bottles and vessels, Microscope slides, gold filters

HotBlock™ for Metals Digestions


The HotBlock™ Family of Digestion Systems provides cleaner, more economical digestions.
The HotBlock™ systems from Environmental Express stand up to the acid environment of your fume hood while reducing your cost of analysis. Made of Teflon® coated graphite and other non-metallic materials, HotBlocks eliminate corrosion and sample contamination that corrosion can cause. HotBlocks have been approved as a suitable means of performing EPA digestion methods such as 3005, 3010, 3050A, 3050B, 200.2 and 200.7.

HotBlock™ systems simplify and speed your digestions by use of low cost, disposable digestion vessels. These vessels also serve as graduated cylinders and as sample storage containers. The polypropylene digestion vessels eliminate the need for glassware and associated glassware cleanup. Digestion vessels contain no detectable background contaminants and do not require acid washing prior to use. Digestion vessels are graduated, eliminating the need for graduated cylinder. After the digestion procedure is completed, samples can be brought up to volume and capped for storage.

Because the HotBlock’s heat surrounds the digestion vessel, they require less energy and radiate less waste heat than traditional acid digestions with hot plates. Electrical energy required per sample is reduced by as much as 75%. The low surface temperature of the block and non-breakable plastic vessels makes sample handling safer as well.

Moving samples around a hot plate is a thing of the past with HotBlocks™. The etched-foil heating mat that provides thermal energy to the HotBlock™ covers the entire surface area of the graphite block. This allows maximum sample-to-sample temperature uniformity. HotBlocks™ maintain a point-to-point temperature of  ± 0.5oC and provide a temperature uniformity ± 1.5oC from sample to sample. This temperature uniformity allows all samples being digested to evaporate at the same rate thus providing little chance for cross contamination and more uniform recoveries.

All HotBlock™ models are now protected from runaway temperatures by the Safe-Sample™ feature. In the unlikely event of a runaway temperature situation, an audible alarm in the HotBlock will sound and electrical power to the heater mat is interrupted. This prevents the potential loss of samples due to boiling. The alarm continues until the block is turned off by the operator.

sc100,36 Sample Capacity HotBlock 36 Sample Capacity HotBlock™
The SC100 with its 36 sample capacity was the first model in the HotBlock™ family and is used daily in hundreds of laboratories around the world. All electronics are self contained and isolated in a separate compartment below the block — no need for a separate controller and clumsy cables. This energy efficient unit draws a maximum of 1080 watts and generates very little waste heat.

The SC100 is supplied with two 18-place polycarbonate racks (catalog number SC200) to facilitate the loading and unloading of samples. These racks can utilize any style of 50mL digestion vessel listed, we recommend our SC475 disposable, screw cap polypropylene digestion cups.

110mL Capacity HotBlock™
The SC150 is designed for the digestion of larger samples. As its standard digestion vessel, it uses the SC490 screw-cap cup with polyethylene liner in the lid. Made of polypropylene, this cup is naturally clean and has a 125mL capacity. This vessel provides faster sample reduction times than the 50mL models due to its wider mouth.

The unit has a twenty five sample capacity. Each block comes standard with one set of two racks (SC225) for easy handling of multiple samples. As with all other HotBlocks it is completely corrosion-free and the graphite block is Teflon®- coated.

sc150, 110mL Capacity HotBlock

sc154, 54 Sample Capacity HotBlock

54 Sample Capacity HotBlock™
The large capacity SC154 Hot Block will digest up to 54, 50mL samples simultaneously in just a 15 X 21.5" footprint. Constructed of Graphite and Kydex® the corrosion-resistant SC154 was designed for environmental and other acid digestions prior to metals determinations. The SC154 uses a maximum of 1065 watts of power and will maintain sample uniformity to ±1.5°C. Heat is provided by a low-wattage heating mat that provides extremely uniform heating to all parts of the block. The compact size of the SC154 allows it to fit comfortably inside the HEPA filtered AirLite hood.

This model comes complete with three 18-place Polycarbonate racks (catalog number SC200). These racks allow the operator to load or unload 18 samples at once. Racks accommodate any style of 50mL digestion vessel. We recommend our SC475 disposable screw cap polypropylene cups.

15" x 15"
13.1 cm x 13.1 cm
15" x 21.5"
13.1 cm x 54.61 cm
15" x 15"
13.1 cm x 13.1 cm
43 lbs
19.5 kg
65 lbs
29.5 kg
42 lbs
19 kg
Electrical Options:
120VAC, 9 A
220/240VAC, 4.5 A
120VAC, 14 A
220/240VAC, 7 A
120VAC, 9 A
220/240VAC, 4.5 A
Sample Capacity:
Nominal Sample Size:
Temperature Range:
to 180oC
to 180oC
to 180oC
Type K
Type K
Type K
12 month
12 month
12 month