Types of Nextteq Detector Tubes

Types of Nextteq® Detector Tubes

Understanding the Types of Nextteq Detector Tubes:

All Nextteq® detector tubes fall into one of the five following categories: ï»¿

Below is the detailed description within each category.  After taking a sample, for most all tubes, the concentration can be read by visually looking at the length of stain directly on the tube.  For some, a color chart or concentration chart is used for determining the concentration, and for some there are humidity and/or temperature corrections that must be applied to obtain the exact concentration.


All Nextteq® detector tubes come with an instruction sheet which is contained in each box and can also be viewed or downloaded on-line. In addition, all Nextteq detector tubes have a data sheet (a.k.a. handbook page) which contains relevant information for each tube and can be viewed or downloaded on-line.  Both the instruction sheet and the data sheet are key pieces of documentation that must be read prior to taking a sample or to obtain an accurate reading.


Warning:  To obtain accurate and reliable readings, all Nextteq-branded detector tubes must be used with the NX-1000 Sampling Pump.

âžž (1)  Short Term Tubes

(Tubes that are read immediately after a sample is taken)

Required apparatus:  the Nextteq® NX-1000 pump

> Short Term - Length of Stain Tubes

Short term – length of stain tubes (NX100 and NX200 series).

Ninety percent of all Nextteq detector tubes fall into this category.


There are 4 scenarios described below in which the concentration is determined by reading the length of stain tube.  After determining the concentration, you may need to apply a correction factor for humidity and/or temperature as identified on the tubes instruction sheet to obtain a final reading.


1)  Read the concentration directly from the tube for a specific target gas. 


2) Read the concentration directly from the tube for a different application – these tubes are identified with an * in the Nextteq Detector Tube Guide or the on-line searchable database and fit into one of the two scenarios:


i. Direct read from the tube for a different application. 

• For example: NX202*, a Phenol Tube, is a direct read from the scales printed on the tube but is used to detect Cresol. 

ii. Direct read from the tube and use a conversion graph or table obtained from the instruction sheet for a different application. 

• For example: NX189*, a Methyl Methacrylate Tube, is a direct read from the scales printed on the tube; however, the reading is converted to detect Allyl Alcohol using a conversion graph or table. 

3) Short term – special concentration chart detector tubes have no scale printed on the tubes but length of stain is read using a concentration chart. The concentration chart is obtained in the instruction sheet.

4) Short term – special conversion chart tubes use conversion charts available upon request for special applications at 20°C or 68°F. 

(See Table 1 in the Nextteq Gas Detection System Detector Tube Guide.)


NOTE: This chart is applicable for measurements taken at 20°C (68°F) using 3 pump strokes.

> Short Term - Color Chart Tubes

1) Short term – color chart tubes/Multi-teq ™ tubes (NX300 tube series) -- tubes that have several sections of specific reagent that will change color to identify the type and qualitative concentration of gas present. Two tubes (NX301 and NX302) for Organic and Inorganic gas detection.

2) Short term – color chart tubes/color intensity tubes (NX119SA & NX119SB)

–tubes whose reagent sections will show a change in color intensity proportional to the concentration of the target gas using a color intensity chart.

> Short Term - Crime Scene Tubes

Short term – special crime scene tubes (NX700 series) used in crime scene investigations.


  • NX701-NX702: Arson investigation for gasoline and/or kerosene.
  • NX711 thru NX714: Specific gases in blood.

A control orifice is needed for the NX-1000 pump.




  • NX715: Paraquat Dichloride in blood and urine. Uses an injection method. 


(See Table 3 in the Nextteq Gas Detection System Detector Tube Guide.)

âžž (2) Continuous Sampling Tubes - TWA

(Tubes that are read after extended period of time) 

Required apparatus:  A constant flow sampling pump

> Continuous Sampling - Length of Stain Tubes

1) Continuous Sampling – direct read tubes (NX600 series) – Time Weighted Average (TWA) tubes require a constant low flow pump like the Nextteq NX-300 – highly accurate NIOSH/OSHA/ACGIH TWA results from these tubes when compared to passive dosimeter tubes. Results are obtained over an extended period giving a clear and distinctive line of demarcation. 


(See Table 4 in the Nextteq Gas Detection System Detector Tube Guide.)

Nextteq® NX-300 used for TWA Tube

2) Continuous Sampling – direct read tubes (NX500 series) require a constant flow pump like the Nextteq NX-1200 – Special high sensitivity tubes for Indoor Air Quality applications. Results are obtained over an extended period of time.


(See Table 5 in the Nextteq Gas Detection System Detector Tube Guide.)

 Nextteq® NX-1200 required for direct read tubes

âžž (3) CBA tubes

(Tubes used for compressed air testing)

Required apparatus:  the Nextteq® CBA kit with Nextteq® regulator

> CBA Tubes - Length of Stain Tubes

CBA tubes - direct read tubes (NX800 series) are used with a Nextteq Regulator Assembly found in the Nextteq CBA Kit and provide a simple method for detecting contaminants in compressed gas and supplied air.


(See Table 6 in the Nextteq Gas Detection System Detector Tube Guide.)

âžž (4) Solution Tubes

(Tubes used for testing dissolved substances in liquids)

No apparatus required.

> Solution Tubes - Length of Stain Tubes

Dissolved Substances – direct read tubes (NX400 series) that provide economical on-the-spot detection of trace chemicals in liquids.


(See Table 7 in the Nextteq Gas Detection System Detector Tube Guide.)

âžž (5) Passive Dosimeter Tubes - TWA

(Tubes that are read after extended period of time) 

Works with Nextteq Dosi Tube Holder

> Passive Dosimeter - Length of Stain

Continuous Sampling – direct read dosimeter tubes (NX900 series) – Time Weighted Average (TWA) tubes  - Results are obtained over an extended period giving a clear and distinctive line of demarcation. 


The Nextteq Dosimeter Tube holders can be used to clip the tube to one's lapel or on a belt.  The tube can also be placed in an area and read at a later time.

Share by: