Transform Your Measurements with Comprehensive Quality Assurance and Process Control

Our test systems ensure that your measurements yield reliable and verifiable analysis results. We prioritize quality, both for you and for us. Each of our products undergoes rigorous functional and approval testing. However, users are still responsible for implementing quality assurance in line with standard laboratory practices. For our photometric test kits and chemical rapid tests, as well as our instruments, we provide an extensive array of process control options.

Section Overview:

• Analytical Quality Assurance (AQA) of Spectroquant^® System
• Recommended Reference Materials
• Quality Documentation for the Spectroquant^® System
• Analytical Quality Assurance (AQA) in RAPID Chemical Testing

Analytical Quality Assurance (AQA) of Spectroquant^® System

All products undergo rigorous testing in our quality control process, ensuring reliability through strict raw material checks, effective in-process controls, and detailed final inspections. However, users must still perform their own AQA in line with GLP.

The Spectroquant^® AQA concept encompasses all aspects of internal quality control (IQC). Analytical Quality Assurance (AQA) ensures that your results are reliable and meet good laboratory practice (GLP) standards. This process includes three key qualifications: Installation Qualification (IQ), Operational Qualification (OQ), and Performance Qualification (PQ). We provide support for a complete IQ, OQ, and PQ documentation, with target values and tolerances included in certificates or even pre-programmed in the instruments. Thereby your measurements become proven, verifiable analytical results. We give more details on the individual steps in the following. Contact your local representative to answer any remaining questions about our quality assurance services.

Spectroquant^® AQA Concept: 3 Steps to Quality

1. Photometer Check - AQA1 covering System Preparation: Installation Qualification (IQ) and Instrument Check: Operational Qualification (OQ)
2. System Check (AQA2) covering extensive Performance Qualification (PQ) of the system
3. Matrix check (AQA3) identifying and mitigating sample-derived errors

Photometer Check (AQA1)

System Preparation: Installation Qualification (IQ)

The Installation Qualification (IQ) verifies that the delivered equipment matches the purchase order and ensures correct installation. Documentation for IQ is available for all Spectroquant^® instruments.

Instrument Check: Operational Qualification (OQ)

The Operational Qualification (OQ) confirms the instrument's functionality across its entire operating range, following defined procedures. All Spectroquant^® instruments undergo this check using certified color standards or Certipur^® UV/Vis standards.

System Check (AQA2)

Performance Qualification (PQ) is the most comprehensive step in Analytical Quality Assurance, verifying product-related functionalities through the measurement of method-specific standards and real samples. The System Check evaluates the entire system—including the instrument, test kit, standard, pipette, and operator—using standard solutions to ensure all components function correctly.

Matrix check (AQA3)

The Matrix Check identifies measurement errors caused by foreign substances in samples, which can significantly affect results. We have tested various compounds to establish the maximum concentrations that can be present in a sample without causing errors, as detailed in the package insert (IFU) of each Spectroquant^® test kit. For complex or unknown samples, we recommend analyzing interferences based on recovery rates and employing appropriate countermeasures, such as sample pre-treatment.

How It Works?

Depending on sample concentration and test kit range, you can use two methods: spiking with standard solutions or diluting with water. For convenience, Spectroquant^® CombiChecks offer a CombiCheck R-2 solution for one-time standard addition (spiking). To maintain the sample matrix, add highly concentrated spiking solutions in small volumes. The AQA3 program in Spectroquant^® Prove spectrophotometers will guide you through this process step-by-step for highest convenience.

Recommended Reference Materials

Analytical Quality Assurance is crucial for ensuring accurate measurements. Whether analyzing drinking water, process water, or wastewater, you can trust our products for accuracy. What standard is recommended for use with our test kits is listed in the respective Instruction for Use. An overview is given in our brochure “Undisputed Accuracy for Your Quantitative Results”.

In many cases we provide pre-diluted standards with concentrations tailored to the measurement range of our test kits for a maximum ease-of-use —no dilution, no doubts, and no delays.

Where this is not possible, we offer standard solutions in higher concentrations that need to be diluted or pure substances for standard preparation. Also here, we provide detailed instructions on how to prepare standards with the right concentration for your AQA.

We provide detailed Certificates of Analysis for all our standards with the Confidence interval at 95% probability, readily available for download via our website.

An overview over our complete reference material portfolio can be found here including definitions and more information about the different quality grades of standards, reference materials, and certified reference materials available.

Spectroquant^® Single Standards – Diluted Reference Materials

Achieve absolute precision with our ready-to-use diluted reference materials (RMs), ideal for quality control in photometric methods, such as Spectroquant^® test kits. Our diluted reference materials guarantee precision with exact concentrations, expanded measurement uncertainty, and direct traceability to NIST primary reference materials, ensuring your results are accurate and globally comparable. 

Explore the diluted RMs here.

Spectroquant^® CombiChecks – Multi Standards and Spiking Solutions

CombiCheck contains multi-parameter standard solutions for checking the overall system – from test kits and instruments to individual working procedures. Each pack contains one standard solution and one addition solution, both of which are directly traceable to NIST primary standards.

When the specified concentration of the standard solution is found, the entire analysis system is in order. If there are deviations from the stated value, use the addition solution to identify errors due to interfering substances in the sample matrix. In case the recovery rate is insufficient (beyond specified tolerances), analyze and eliminate the cause through appropriate countermeasures, such as sample pre-treatment.

More information can be found here.

Explore the CombiCheck solutions here.

Certipur^®/TraceCERT^® standard solutions

In some cases, diluted standards are not stable. Here you can rely on the superb quality of our Certipur^® and TraceCERT^® Certified Reference Material Standard Solutions. Originally designed as Ion Chromatography or ICP/AAS spectroscopy standards, they are also compatible and can be recommended with the Spectroquant^® system.

Explore our comprehensive selection of reference materials here.

Photocheck standards for instrument

The photometric accuracy and linearity of photometers are checked using check solutions for Spectroquant^® photometers (445/446 nm, 520/525 nm, and 690 nm). Spectroquant^® PhotoCheck secondary standards are compliant with ISO 9001, ISO 14001 and ISO 17205 guidelines, and calibrated with instrument qualified with NIST standards.

The Photocheck content:

• Check solutions for 3 different wavelengths
• 2 zero cells
• 2 cells for checking the bar-code reader (only for Spectroquant^® photometers) more information can be found in the user guide (IFU)

Quality Documentation for the Spectroquant^® System

Quality Certificates, Lot Certificates, and Definition of Quality Terms The Spectroquant^® system facilitates safe analysis through user-friendly test kits and certificates that ensure accurate measurement results. Compliance with international standards and national regulations necessitates such documentation, particularly from accredited laboratories. For each Spectroquant^® test kit a quality certificate (CoQ) is available that includes all essential quality data, serving as a resource especially for auditors at accredited laboratories. It can be found in the document section on the product detail pages. Additionally, for each Spectroquant^® photometric test kit we provide a certificate of analysis (CoA) that shows batch-specific information, detailing the results of all quality tests performed. All certificates are available for download on the product detail pages, CoAs can also be found via the global Documents-section on this website.

For a clearer understanding of our quality and lot certificates, please find below the definitions of quality terms. The rigorous quality control and lot-specific documentation associated with each Spectroquant^® test kit position us as an ideal partner for quality-conscious customers, especially those who recognize the significance of quality-controlled products in their laboratory operations and hold certifications in ISO 9001, ISO 14001, and ISO 17025.

Definition of Quality Terms in Spectroquant^® Certificate - Enhancing Understanding of Our Documentation

Below are definitions of the quality terms utilized in our quality and lot certificates:

• Sensitivity of the Method: The slope of the calibration curve as defined in ISO 8466-1.
• Limit of Detection: The minimum amount is the lowest concentration or amount of a substance that can be reliably detected. This limit serves as a decision threshold for the presence of a component. The detection limits given in the certificate of analysis are according to SM 1030 C (lower limit of detection and method detection limit), ISO TS 13530 and DIN 32645. The regulations DIN 32645, ISO TS 13530, and APHA 1030 C each describe a different way to calculate the values.
• Limit of Quantification: The quantification limit is the lowest concentration of a substance that can be reliably quantified and reported with acceptable precision and accuracy in a given analytical method The limits are according to ISO TS 13530 and DIN 32645.
• Confidence Interval at 95% Probability: This interval indicates the range within which the true value is expected to lie, determined by a specified probability. Values from random sample surveys inherently carry uncertainty and serve as estimates of the unknown parameters of the population of interest. Utilizing confidence intervals in measurement results allows for quantifying the reliability of the outcomes, in accordance with ISO 8466-1.
• Standard Deviation of the Method: The most commonly used measure of dispersion as defined in ISO 8466-1.
• Variation Coefficient of the Method: The standard deviation expressed as a percentage of the mean, according to ISO 8466-1.
• Measurement Uncertainty: Measurement uncertainty states the variability associated with a measurement result. The measurement uncertainty stated in the certificate is referred to a 95 % confidence interval, that means that there is a 95% probability that the true value of the measured quantity lies within a specified range around the measured result, considering all possible sources of error. This uncertainty can arise from various factors, including instrument limitations and the measurement process itself. Expressing measurement uncertainty is essential for understanding the reliability and accuracy of the results. Bias in the context of measurement uncertainty refers to a systematic error that consistently skews measurements away from the true value. It represents a consistent deviation in one direction, either overestimating or underestimating the actual value. According to DIN ISO 11352 2013-03 (Bias according to chapter 8.3.2) (in the middle of the measuring range
• Accuracy: Degree to which a measured value reflects the true value of the quantity being assessed. It combines both trueness and precision, indicating how close a measurement is to the actual value and how consistently it produces similar results. A measurement system is considered accurate if its results are both close to the true value (trueness) and consistently reproducible (precision). In essence, accuracy provides an overall assessment of the reliability of measurements in representing the true characteristics of the data being studied. According to DIN ISO 5725-1 (in the middle of the measuring range).
• Precision: Describes the consistency and repeatability of measurements. It indicates how closely multiple measurements of the same quantity agree with each other, regardless of their closeness to the true value. According to DIN ISO 5725-1 (in the middle of the measuring range).
• Trueness: Trueness refers to how closely measured values align with the true value of the quantity being measured. According to DIN ISO 5725-1 (in the middle of the measuring range).

Quality Certificates in Spectroquant^® Test Kits - Your Document for Consistently High Product Quality

The quality certificate, providing users with a quick overview of all relevant quality data, which can be downloaded from each product detail page in the document section.

Included Information:

• Measuring range
• Sensitivity
• Limit of detection
• Limit of Quantification
• Confidence interval at 95% probability
• Standard deviation of the method
• Variation coefficient of the method
• Number of production batches used to create the quality certificate
• Accuracy of the test

For many test kits we already have extended the CoQs even further and will continue to implement the changes to provide updated CoQs including the following information:

• Measurement uncertainty
• Trueness
• Precision

To derive the statistics listed above, data is averaged from multiple batches, offering users clear insights into manufacturing accuracy and indicating the long-term quality they can depend on. The quality data also facilitates comparisons for auditors to assess the accuracy of results obtained in the customer's laboratory when using a Spectroquant^® test kit.

In addition to characteristics such as confidence level, standard deviation, and variation coefficient, which are established according to ISO 8466-1, the lower limit of detection and method detection limit values are particularly significant. The lower limit of detection corresponds to the concentration of the blank, while the method detection limit represents the lowest measurement value that is statistically distinguishable from the blank value.

Pre-Programmed Blank Values

Due to the reproducibility of this data, verified by our QC for every produced batch, the reagent blank value for each method is pre-programmed directly into Spectroquant^® spectrophotometers. This allows users to rely on the pre-programmed value, eliminating the need to prepare a blank and manually calibrate the instrument. Only in some cases and where accuracy could be further increased e.g., in the lower measurement range, we recommend measuring against a freshly prepared reagent blank for the current batch. For the calibration of test kit methods, we consistently adhere to international and German standards.

Lot Certificates for Spectroquant^® Test Kits

Each Spectroquant^® test kit is accompanied by a lot certificate, which is a crucial document containing all quality indicators specific to that lot, including article number, batch number, measurement range, and lot-specific quality data. These documents can be downloaded from each product detail page or via the global Documents-section on this website.

The lot-specific quality data includes:

• Slope
• Ordinate segment
• Reagent blank
• Confidence interval at 95% probability
• Standard deviation of the method
• Variation coefficient of the method

For further information on the definitions of quality terms, please refer to the section “Definition of Quality Terms in Spectroquant^® Certificates”.

Comparable Results

When generating the lot certificate, we establish tolerances for all relevant measured values. Compliance is verified through the review of quality data produced by the control laboratory. Each lot certificate displays both the defined standard value and the value obtained during quality testing, enabling users to compare results effectively.

Highest Accuracy and Reliability

We strictly adhere to the requirements of ISO 8466-1. While a standard 5-point calibration method can be utilized, we implement a more rigorous 10-point calibration system to ensure the highest accuracy and reliability for users.

By extending the batch certificate to a second page, customers receive not only the important actual/nominal value comparison for the Spectroquant^® test kit but also the reference values used for calibrating the photometer. This information, such as the slope, is particularly valuable for laboratories that regularly review results and analyze relevant quality data.

Accepted Documents for Audits

Laboratories are required to verify data quality, including calibration accuracy, lower limit of detection, and method detection limit at least once a year. By comparing our provided data with their own quality data, labs can easily present auditors with results that demonstrate compliance with regulatory standards. Users of our test kits only need to submit the corresponding lot certificates to the auditor, as we are a certified supplier maintaining an ISO 9001 documented quality management system. This eliminates the need for receiving inspections, as we already validate the outgoing quality of our test kits through the lot certificates, saving users both time and money while ensuring maximum safety.

Overall, by utilizing the lot certificates provided with Spectroquant^® test kits, customers can focus on reviewing their performance using standard solutions as part of their quality assurance processes. Occasionally, it may also be beneficial to assess data quality for critical samples. For this purpose, we offer Spectroquant^® CombiCheck products for many of the test kits.

Analytical Quality Assurance (AQA) in RAPID Chemical Testing

There are different methods known as Rapid Chemical Testing including colorimetric and reflectometric test kits. Depending on the test requirements and expected accuracy various colorimetric tests provide semiquantitative results and include test strips and visual test kits. For higher accuracy the reflectometric test strips provide quantitative results using the RQflex^® 20 reflectometer.

MQuant^® test strips, pH indicator strips and paper

The pH value and/or chemical concentration is determined by visual comparison of the reaction zones of the test strip/paper with the fields of the color scale provided with the product label. The colors of the reaction zones must be clearly assignable to the colors of the color scale.

To check test strips, most suitable standard solution and handling please refer to the method control described in the user guide (IFU) of the respective test strip. If the test yields the predetermined concentration of the standard solution, then this means that the entire analysis system is operating correctly.

MQuant^® Colorimetric Test Kits and Titrimetric Test Kits

The chemical concentration is determined by visual comparison of the color reaction of the sample with color comparison scale provided with the either disc comparator or color cards of the respective test kit. After sample preparation the color result of the sample must be clearly assignable to a color of the color comparison scale.

To check test reagents, measurement device, most suitable standard solution and handling please refer to the method control described in the user guide (IFU) of the respective test kit. If the test yields the predetermined concentration of the standard solution, then this means that the entire analysis system is operating correctly.

Reflectoquant^® Test Strips and Instrument

For the instrument-based Rapid Chemical testing, it is recommended to check the reflectometer with the RQcheck set before each measurement series.

This step allows performing the selectable quality assurance procedure "RQcheck" to ensure nominal functionality of the instrument. The set contains a grey check strip and a corresponding barcode strip.

If the RQcheck fails, perform a recalibration using the RQflex Recalibration Set and repeat the RQcheck.

The recalibration set can be used for the RQflex^® 20 reflectometer. The set contains a calibration strip, an internal standard, and a barcode strip for calibration. It is used for the initial calibration of an instrument before the first use (every instrument is delivered with a recalibration set) and for recalibration as stated in the manual.

For more details, see the documentation of RQflex^® 20:

• Operating Manual
• Quick Guide
• To check test strips, test reagent, instrument, most suitable standard solution and handling please refer to the "Method control" section of the user guide (IFU) of the respective test strip.

Influence of Foreign Substances – Matrix Check

Foreign substances present in a sample can interfere with the determination. To determine these interferences, there are two methods:

• Identification of matrix effects by means of dilution: This method is especially suitable for samples with analyte concentrations falling within the upper half of the measuring range of the used test kit.
• Identification of matrix effects by means of standard addition: This method is especially suitable for samples with analyte concentrations falling within the lower half of the measuring range of the used test kit.